Buck Jumping on Mass

Terry Bendall
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Re: Buck Jumping on Mass

Postby Terry Bendall » Mon Apr 20, 2020 8:42 am

Will L wrote:Terry, having taught myself how to use a standard iron effectivly, I find I can do everything I need the traditional way.


Thanks Will. At the moment I share that view. I can cope with most things including soldering brass to white metal with an 18 watt iron. :)

Flymo748 wrote:It's possible to model perfectly well without an RSU. I just find it's an extra trick up my sleeve


I am sure that's right Paul. My fairly modest tool kit is gradually being described in the series of articles in the News and I have what I need for the jobs that I do. What I do find is on the fairly rare occasions when I do buy something new is that I start wondering how I managed without it! :) That may well apply should I invest in an RSU.

Terry Bendall

tmcsean
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Re: Buck Jumping on Mass

Postby tmcsean » Mon Apr 20, 2020 10:16 am

My experience is that the RSU is an absolute godsend for the hamfisted modeller, Its one of those equaliser tools that enables you to work far above your innate skill and dexterity level. The two professional modellers I know manage perfectly (literally) well without one but for me it makes Bradwell kits and MJT laminated coach sides possible rather than easier.

Tony

bécasse
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Re: Buck Jumping on Mass

Postby bécasse » Mon Apr 20, 2020 12:23 pm

tmcsean wrote:My experience is that the RSU is an absolute godsend for the hamfisted modeller, Its one of those equaliser tools that enables you to work far above your innate skill and dexterity level. The two professional modellers I know manage perfectly (literally) well without one but for me it makes Bradwell kits and MJT laminated coach sides possible rather than easier.


I don't have an RSU as I decided that its cost (and required storage space) couldn't be justified for the little use I would make of it. I do though have, and have had for a couple of decades, a relatively sophisticated soldering station with a temperature-controlled iron and a full range of bits to go with it. I thought that I was good at soldering before I bought it - it is over half-a-century since I first demonstrated soldered kit construction at a major exhibition - but how much better my soldering techniques, and more important abilities, were with it was real revelation. It even gets used to "solder" broken plastic bits back together!

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Will L
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Re: Buck Jumping on Mass

Postby Will L » Mon Apr 20, 2020 12:29 pm

Flymo748 wrote:...The two main functions the RSU serves are:

(i) Lots of heat - like cast lost-wax sandboxes...


I'm not entirely Luddite about adopting new methods, and relevant to the use or not of the RSU is one of my recent discoveries which I would not now be without. This is 100 degree solder.

This is good stuff for its intended use, that is soldering white metal to brass, because there is no need to tin the brass first. But you do need to beware, the melt risk is high if you’re trying to attach small bits of white metal to big bits of brass. Traditional low melt is to be preferred then, as well as for any white metal to white metal joint.

The real 100 degree solder revelation was that it is absolutely ideal for attaching large cast brass fittings. As is due to come up in this thread when we get there, it really simplified fitting the chimney, dome and safety valve brass castings to the chunky brass tube of the boilers. Or for that matter, cast brass sandboxes to footplates. The joint is as solid as you like, and you can even use the solder as a filler if the fit between casting and boiler leave something to be desired.

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Tue Apr 28, 2020 2:35 pm

Part 12 Completing the basic body shell

The inside story


Both kits come with full cab interiors, and as these very much influence the size of the space into which the motor and gear box are going to have to fit, they need to go in now. The use of the Highlevel Slimliner gearbox with a Drivestretcher (see part 2 ) means that the motor sits in the boiler space, the gearbox is vertical in the firebox and drives the rear axle under the cab floor. Therefore, there is no intrusion into the cab and a complete cab interior will be fitted. The picture illustrates this drive chain, I’ll come back to the torque reaction link later. J65 to the front and J69 at the rear.
Buck drive chains.jpg
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The major part of the cab interior is an etch that folds up to form the cab floor (etched with wood plank detail), the cab back/bunker front, and the shelf across the back of the cab. The bunker front also has a little shovelling plate which folds down into the bunker space to form the coal hole. The J69 etch also includes the lower cab front, in theory. However, as the etch contained an error (the floor is one plank too long), the cab front bits, there are two, have to be removed and fitted separately. The J65 has a separate single lower cab front etch in the first place.

The cab back needs the coal hatch detail to be added around the coal hole/shovelling plate before the bending begins. Once bent, I fitted edges around the shovelling plate which I made of scrap etch, so it is not just a hole into the void when I want to detail it with coal. There are a couple of small boxes which go into the front corners of the cab, the right hand one of which will eventually carry the screw reverser (all J65s and my chosen J69 were nominally passenger locos, the GER only fitted lever revers to shunters). These boxes need folding up and will be fitted at this stage. Beyond that, there is a fair bit more detail to go into the cab interior, but not now, we will come back to it later.

Assembly, at last.

Having got all the bits ready, it’s assembly time. But first, the J69 cab sides have a small etch which represents the step into the cab. This should be applied first at the bottom of the door opening and I probably should have mentioned it a couple of posts ago.

Starting with one tank/cab/bunker side, we are going to tack solder to it all of the following. The bunker back, the bent-up cab interior, the cab lower front and the tank front piece. The cab interior needs to be carefully aligned with the rear edge of the cab door and the cab step detail. On the J69 the floor fits against the cab step etch soldered to the cab side that I mentioned just now. On the J65 it sits on the step detail which folded up from, and forms part of, the footplate. The fit needs checking before we progress further. Then in goes the lower cab front piece (or half of it in the case of the J69) and the tank front piece. Although they are not going to be fitted yet, it is wise to ensure that the cab spectacle plates, front and back, both sit on the cab interior and align properly with the top edge of the cab sides. They won’t if the cab interior isn’t in the right place.

The J65 kit instructions suggest that the plate provided to top off the bunker coal space should be fitted at this stage, the J69 instructions don’t. I’m with the J69 as this would close off an otherwise useful space for adding weight, or a DCC chip if that’s what turns you, or your locos, on.

Now we should ensure the assembly so far will fit squarely on the footplate before tacking on the second cab side, not forgetting the second cab front piece on the J69. One last careful check that the whole tanks/cab/bunker unit sits squarely on the footplate and aligns where it should, before running in solder to complete all the joints made so far.

You get one last chance to ensure the captive bolt on the J65 footplate is firmly attached, as we’re not going to be able to get to it again, then the whole assembly is soldered to the footplate. After that fit those little boxes into the cab front corners. On the J69 the kit provides pieces to form the tank backs. These fit directly in front of the cab front pieces, but unlike them, sit on the footplate. They exist to form a ledge onto which the tank tops will fit sometime soon. The J65 manages without.

Once satisfied the whole cab etc assembly is correctly attached to the footplate, remove those cab handrail positioning jigs from the cab sides, clean up and drill the footplate 0.5mm for the cab handrails just inside the cab door.. In theory these handrails are tapered from bottom to top but I’m afraid I chickened out on that and just used plain old 0.5mm wire which is soldered in now.

Enough for now

Having reached this stage we have enough of the body available to check that motor gearbox and pickups will fit in the finished body. So in the next few posts it will be back to the chassis to finish them off. One more picture to show the bodies built to this stage and showing that the chosen motors, (Mashima 1024s my favourite motor, now sadly unavailable) are going to fit. The J69 to the front, shows that the motor goes in no problem, while for the J65 to the rear, it is a tight fit.

buck body motor fit.jpg
buck body motor fit.jpg (585.52 KiB) Viewed 2660 times


RC 32038

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Sun May 03, 2020 7:50 pm

Part 13 Back to the Chassis – Further Mechanics

In this post we are going to settle the configuration of the gearbox, sort out the torque reaction link and build ourselves some pickups

Configuring the Motor/Gearbox

Now we have the basics of the body we can check that the motor/gearbox will fit into it. The key point is the fit of the gearbox in front of the cab, although on the J65 the motor has to run into the boiler tube as well. I fitted the Slimliner + gearbox with a Drivestrecher (Highlevel product names) so it can reach the axle under the cab floor without encroaching on the cab. I went with the 54:1 gear ratio as the locos have small (4ft) wheels and the speed calculator on the Highlevel website says that, given the 1024 motor, I would get a scale top speed of about 50 mph. This seems more than adequate. The diagram that follows has Highlevel Component diagrams borrowed from the their website so you can see what I’m talking about.
Buck gearbox components.jpg
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When you put the two together, the Drivestreacher is free to revolve around the bottom shaft of the gearbox. In a chassis with suspension it is necessary to fix the joint between the two before you can put any power through it. The angle between them determines if, and exactly how far, the gearbox comes in front of the cab front. It also fixes the height of the motor above the chassis which is important to me because my pickup assemblies sit in the space between the two. However don’t forget to allow space above (a full 1mm) and round the motor to allow for suspension movement. In the past I have done “clever” things with catches and pins to fix the Drivestrecher to gearbox in an adjustable way, these days I’ve given up trying to be clever and make do with a dab of solder.

A proper reaction to torque

Once you’re sure you can get the motor/gearbox where they need to be, the next thing to sort out is how the Torque Reaction link is going to work. The rational for such things is explained in the Scalefour Digest 41.0 section 12.6. Some don’t seem too clear as to why you need one of these, and what it does. Such a thing is only necessary on a chassis where the driven axle is not rigidly fixed, so one is needed for any fully sprung chassis, like CSBs or any compensated chassis where the driven axle is compensated. Under load, the motor/gearbox will try to revolve around the driven axle. A proper reaction link will prevent it from doing this while not affecting the axles freedom to move up and down vertically. Without one, the motor/gearbox will turn till it hits something solid. and depending on the way that happens the driven axle can be forced up, or down. You may get driving wheels that visibly hop, otherwise inexplicable derailments, or, in the worst case, a chassis that jams solid. With a free running chassis pulling light loads; it is true that some people do seem to get away with not having one at all, or with solutions which are not right according to theory. However, problems are prone to appear if you have a stiff chassis or you ask your loco to pull heavy loads.

On these locos, it is implemented by a horizontal link under the cab floor from both sides of the back of the gearbox to a single pivot point on the other side of the driven axle. It allows the gear box to both rise and fall with the driven axle and to rock left and right with it to. The link on the J69 is illustrated.
Buck J69 t link.jpg
Buck J69 t link.jpg (390.85 KiB) Viewed 2550 times


On the J65 in particular, as the motor extends into the boiler tube, it wasn’t clear if I would be able to fit the chassis into the loco with the link in place. As a result, I designed it so the link could be done up from beneath once the chassis was in the loco. In practice this proved unnecessary, just.

A good line in pickups

I am very much in favour of top wipers bearing on the wheel tread, as this means they tend to be invisible, gets them well out of the way so as to avoid accidental adjustments during handling and wheel cleaning, and prevents them getting caught on track misalignments or debris. It also means they run on the one bit of the wheel you already have to keep clean. I’ve been through the way I design and build pickups before at some length click to visit “Pickups for the J10” part 1 and part 2.

buck Pup oview.jpg
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The finished result looks like this. The J65 Chassis has the finished job in place, the bits for the J69 pickups are top and bottom. The copper clad slab they are built on fits snugly between the edges of the frames, and bolts on to the top of the centre chassis spacer which was tapped 12ba in anticipation. The black lump is the socket end of the two pin plug I use to connect the motor to the pickups, and provides a point where DCC could be incorporated if it is ever required. Note that the middle and rear wheel pickups are above frame level as they come under the tanks where there is a hole in the footplate and plenty of room. The front axle pickups are outside the frames and under the footplate where there is just enough room behind the valance to hide them.

Undressing the J65 and running them both in

Clearly having fitted the pickups, now is the time to do the work needed to ensure the chassis runs as it should under power. It was at this stage that the decision was taken to build the J65 as a 2 4 0T. This was in deference to the fact it was proving difficult to find a photo of my chosen loco, 7155, in any other state. The crank pins in the front wheels are left in and the place of the connecting rods filled in with a couple of 12ba washers. This gives a fair representation of the prototype. Another washer tidied up the appearance of the rod end on the middle wheel. In case you’re wondering, the GER placed these locos into the “prototype for everything” category by articulating their rods on the middle crankpin.

A little judicious reaming out of the coupling rods was all that was required to get them both running nicely. Once I’m happy a chassis is stiff spot free I leave it to spin its wheels against a stop. If the motor runs hot, then it is not free enough and more work is needed until it runs cool. If it goes the wrong way, I just need to put the two pin plug in the other way up. Once that’s done, it is time to move on to adding most of the cosmetic below footplate detail.

RC 32288

davebradwell
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Re: Buck Jumping on Mass

Postby davebradwell » Mon May 04, 2020 8:43 am

Sorry WIllL but your torque arm in the photo doesn't allow the motor with axle to rock from side to side as you claim without bending the rather stiff looking wire. It will try to turn about the lh connection which is prevented by the hornblocks. It's the double connection to the gearbox that spoils it. A single link on the centreline would do it with a loose attachment to a gearbox bracket like the lh end. Current arrangement might be improved a little with a shorter triangle of wire and longer straight bit to give more flexure.

In addition, as you have pointed out yourself in the past, once the point of flexible attachment to the gearbox strays from being directly above the axle there is an increasing vertical component of the torque reaction and the motor weight is adding to it in. These stretched drive configurations do present quite a challenge for a motor restraint and you may be better off with a vertical support towards the end of the motor, as far as possible from the axle.

DaveB

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Will L
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Re: Buck Jumping on Mass

Postby Will L » Mon May 04, 2020 3:16 pm

davebradwell wrote:Sorry WIllL but your torque arm in the photo doesn't allow the motor with axle to rock from side to side as you claim without bending the rather stiff looking wire. It will try to turn about the lh connection which is prevented by the hornblocks. It's the double connection to the gearbox that spoils it. A single link on the centreline would do it with a loose attachment to a gearbox bracket like the lh end. Current arrangement might be improved a little with a shorter triangle of wire and longer straight bit to give more flexure.


Dave

I think I see what you mean and the danger it represents. My first design for the link did include a single attachment in the centre of the gearbox, but I ran into various problems with it, mostly in getting it to resist the for and aft forces. The low point of attachment on the gearbox didn't help and nor did the a lack of clearance between the gearbox and the front of the cab. The J65 in particular is a very tight fit and it was that one I did the trial and error on. The final design as published met all my requirements and certainly appeared to work to me. I was working on the principle that so long as the hole the hook passes through at the chassis end of the link is a loose enough fit on the wire it will be free to turn the few degrees required.

However, interest aroused, I thought I'd try a little test. If, as you suspect, this arrangement will prevent the driven axle from rocking, the chassis will fail the classic running over a matchstick trick. That said, using a matchstick is really overdoing it, as the design limit for movement on my chassis is 0.5mm either side of the centre, therefore I chose a steel rule which is 0.6mm thick

Buck TR test 1.jpg

This is my test rig. One driven wheel is sitting on a steel rule and one hopes that the other five wheels should all be sitting on the flat surface. You will also notice that this is the bare chassis which is quite light and the spring wires fitted are for the full loco weight (about 220 gm), and I did wonder if this would prevent the necessary deflection of the driven axle. The chassis was placed into this position and not touched again. I'm in the habit of cutting down my photos to the traditional approved size for the forum so people with slow internet links don't have to wait for them to download. On this occasion I've left them full size so they will enlarge if you click on them. Until I saw the photo's I hadn't noticed the pickup on the wheel in question has been displaced, but it shouldn't make any difference.

Buck TR test 2.jpg

The picture is of the side with the wheel on the ruler. If the springs had been stiff enough to prevent the full 0.6 movement, the middle wheel would have been off the floor. It isn't

Buck TR test 3.jpg

This is the other side. All wheels firmly on the floor, so the drive axle has successfully twisted by the full amount needed, without the assistance of the body weight. I think that means it works as intended.

In addition, as you have pointed out yourself in the past, once the point of flexible attachment to the gearbox strays from being directly above the axle there is an increasing vertical component of the torque reaction and the motor weight is adding to it in. These stretched drive configurations do present quite a challenge for a motor restraint and you may be better off with a vertical support towards the end of the motor, as far as possible from the axle.

You're quite correct that this motor/gearbox configuration isn't the easiest to deal with, particularly when you have little room around the motor to play with. I've always worked on the basis that, to avoid affecting the suspension, the forces in the torque reaction link should run horizontal to the chassis. Your tab in a slot above the axle approach does exactly that, and I won’t forget it if I get an appropriate prototype. However I've always been concerned that restraints on the far end of the motor can't result in horizontal forces. So I avoid them.

David Knight
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Re: Buck Jumping on Mass

Postby David Knight » Mon May 04, 2020 3:41 pm

Since the conversation is about torque reaction links, I have one that seems to work but I would appreciate constructive criticism of it. It is mounted on a modified SEF chassis for an SECR "P" class 0-6-0T and consists of a simple horseshoe shaped length of N/S wire that hooks on a frame spacer under the motor.

IMG_0088 copy.jpg


As an aside to Will, this is the frame we talked about which is now working after I shifted one hornblock an extra .005" and eliminated the bind in the mechanism.

Cheers,

David

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Le Corbusier
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Re: Buck Jumping on Mass

Postby Le Corbusier » Mon May 04, 2020 5:33 pm

David Knight wrote:Since the conversation is about torque reaction links, I have one that seems to work but I would appreciate constructive criticism of it. It is mounted on a modified SEF chassis for an SECR "P" class 0-6-0T and consists of a simple horseshoe shaped length of N/S wire that hooks on a frame spacer under the motor.

IMG_0088 copy.jpg

As an aside to Will, this is the frame we talked about which is now working after I shifted one hornblock an extra .005" and eliminated the bind in the mechanism.

Cheers,

David

Not sure I understand how this set up works? For a torsion link, aren't we trying to prevent rotation without setting up vertical forces that could effect the suspension? I found Dave Bradwells solution elegant and simple ... a restraining cradle preventing lateral movement whilst allowing vertical and rocking movement (https://www.scalefour.org/forum/viewtopic.php?p=70264#p70264). I may be misunderstanding what I am looking at but doesn't your loop allow the motor to rotate up to the point the loop restrains it ... and then surely it will apply downward force through the gearbox and into the axle effecting the functioning of the CSBs?
Tim Lee

David Knight
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Re: Buck Jumping on Mass

Postby David Knight » Mon May 04, 2020 6:36 pm

Fair point Tim. The idea is based on the theory put forward by many who argue that in some engines there is little to no room for the motor to rotate so they don't even bother with a link. Being a belt, braces and a bit of string type I thought this idea a bit tidier plus it let me run the engine without having the "lid" on. I've used something similar on a "Terrier" conversion that also seems to work.

Cheers,

David

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Will L
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Re: Buck Jumping on Mass

Postby Will L » Mon May 04, 2020 6:47 pm

Le Corbusier wrote:... I may be misunderstanding what I am looking at but doesn't your loop allow the motor to rotate up to the point the loop restrains it ... and then surely it will apply downward force through the gearbox and into the axle effecting the functioning of the CSBs?

That would be my view.

David Knight wrote:...As an aside to Will, this is the frame we talked about which is now working after I shifted one hornblock an extra .005" and eliminated the bind in the mechanism.

Pleased I got the diagnosis right and that you were able to fix it. If it now runs nice and smoothly you may well not see any further problems unless you try pulling heavy trains with it. Be wary if it the motor still kicks a bit on each revolution of the wheels.

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Sun May 10, 2020 5:56 pm

Part 14 The Chassis Cosmetic Details, Part 1

What we have left to do on the chassis is to sort out various parts of the brake gear, the sand boxes under the cab and some details on the wheels. The injectors and a few other pipes which do exist below the footplate are actually attached to the body and will be covered when we get to do the plumbing on the completed body..

The Westinghouse Brake

All the Buckjumpers, when Westinghouse brake fitted, have the air reservoir and the brake cylinder fitted under the bunker behind the rear buffer beam. These can be seen prominently in any photo of the bunker end and on the available drawing but were nowhere to be found in either kit. Look back six years in this thread and you will see me requesting information on this very topic. I was finally able to glean enough info to have a crack at them, and the various bits of strapping which visibly attached them to the loco. I could guestimate the sizes and basic features of these two objects from Lyn Brooks’ drawing of the J69, but not exactly were there centrelines would have been. I also had to be careful that, on the J65, the bolt that fixes the chassis to the body had to be accessible between them. All the evidence I have says that the J69 and the J65 would have been very much the same in this area, as in this photo. This is the J65.

Buck westinghouse gear.jpg
(buck westhouse gear.JPG)

Not having any tubes of the sort of dimensions required, I had to scratch build something, which was not entirely strait forward given I live in a lathe free zone. The sizes used were all estimates and the following drawing, done after the event, is to show how they were made. It is not dimensionally accurate. The form and position of the adjacent chassis frame spacer was a little different on the two locos so there were some minor detail differences between the two, but these were not significant

Buck brake cyliners 2.jpg
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How it was done

For the cylinder wrappers I cut strips of 0.5mm brass of the correct width for each one. These were rolled into a tube of roughly the correct diameter. This was a thigh and 1/8 silver steel rod job. I used 1mm brass rod as the core of each one and formers were turned up from scrap brass etch sheet in my Dremel, using a file, sorry. The formers are soldered to the core and the wrapper cut to length and soldered round the formers. The joint in the wrapper is at the top where it can’t be seen so doesn’t need to be perfect. The air reservoir has an in-set end (domed in the prototype but who’s going to know), so just needed filing up square and tidy. The brake cylinder has a base plate which again is scrap etch soldered over the end and filed down to leave a slight lip. The adjacent chassis frame spacer was drilled to take the ends of the two cores where I thought the two centre lines should be. The Reservoir and bake cylinder were then soldered in place. The distinctive strapping which appears to support them both but reality is just cosmetic. For the air reservoir it comes from above, while the brake cylinder is supported from the buffer beam, in theory. For the reservoir, the core is cut off flush with the frame spacers, while that on the brake cylinder becomes its operating arm and will eventually be connected up to the brake actuating shaft which runs across the chassis as shown in the picture.

I’m really quite pleased with the result, estimates as they are, and so I’m not certain I would now welcome a detailed picture of this area of the preserved J69.

RC 32969

Edward45
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Re: Buck Jumping on Mass

Postby Edward45 » Tue May 12, 2020 9:07 am

Will, surely you could have saved yourself a lot of problems, and indeed having to estimate, by obtaining the set of GERS/John Gardner drawings. Drawings L18 and L57 cover both versions of the J65. I'm sure that Lynn would have advised you accordingly.

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Will L
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Re: Buck Jumping on Mass

Postby Will L » Wed May 13, 2020 11:36 am

Edward45 wrote:Will, surely you could have saved yourself a lot of problems, and indeed having to estimate, by obtaining the set of GERS/John Gardner drawings. Drawings L18 and L57 cover both versions of the J65. I'm sure that Lynn would have advised you accordingly.

You are of course right, but it's a bit late now. I let met GER society membership laps some years ago now and hadn't kept pace with what it available from them. Prompted by your reminder I have discovered that, as of this very month, you can buy the full set of GERS loco drawings (mostly by John Gardner but also some by Lyn Brooks) as a download at the very reasonable price £15. Of course I couldn't resist. The down side is that I now know what I've done wrong, not that I'm going to tell you lot.

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Flymo748
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Re: Buck Jumping on Mass

Postby Flymo748 » Wed May 13, 2020 9:30 pm

Will L wrote:
Edward45 wrote:Will, surely you could have saved yourself a lot of problems, and indeed having to estimate, by obtaining the set of GERS/John Gardner drawings. Drawings L18 and L57 cover both versions of the J65. I'm sure that Lynn would have advised you accordingly.

You are of course right, but it's a bit late now. I let met GER society membership laps some years ago now and hadn't kept pace with what it available from them. Prompted by your reminder I have discovered that, as of this very month, you can buy the full set of GERS loco drawings (mostly by John Gardner but also some by Lyn Brooks) as a download at the very reasonable price £15. Of course I couldn't resist. The down side is that I now know what I've done wrong, not that I'm going to tell you lot.


Plenty of credit where credit is due - the range of material available from the GERS is immense, and of great use to the modeller.

The Journal is a seriously heavyweight production as well, and I pore over the photos every time one arrives.

If you model GER, LNER in the area, or BR(E), membership really is a very good idea.

Cheers
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Sun May 24, 2020 5:00 pm

Part 15 - The Chassis Cosmetic Details 2

Rear Sand Boxes

Also visible in the photo that illustrated part 14 are the rear sandboxes. While prototypically fitted under and to the footplate, I have them attached to the chassis. Something said to represent these was included in the kits, but I regret that Mr Rice and I will have to agree to differ on that one. Replacement sandboxes were fabricated from brass sheet, based, again, on the J69 drawing I had available at the time. I drew out the shape needed, cut them out and folded them up as in the following drawing.
buck sand box draw.jpg
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The flat shape folds to form the basic box as in the drawing above. The black spot marks the place to drill the hole where the sand pipe will be attached. The folded box shape will fit snugly into a strip of brass bend to the right angle down the middle. Approx. 30° was about right but it was adjusted until they were a good match. The bent strip has to be trimmed to fit against the small square section from which the sand pipe will exit. Once all is snug, solder the box to the strip, cut and file off the excess metal round the sides and finish the box with the nice round edges you should have on a pressed item. The next picture shows them in production while a picture further down shows one in place on the J69 chassis.

buck sand box.jpg
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While doing this the modern way, by drawing the bits in CAD and getting them etched, would have produced neater and more accurate results, it would also have taken several weeks longer. Although the two nights spent doing all 4 of them was not my most enjoyable modelling, I am tolerably happy with the results. These rear sand boxes were fitted with a 0.45 mm wire “sand pipe” with a sliver of tube added at the joint with the box and which snakes its way down between brake gear and wheel. In case your wondering, the front sandboxes are mounted above the footplate, and the pipe supposedly coming from them was modelled as part of the break gear. Talking of which…

The Brake Gear

I have in fact covered the Buckjumper brake gear some time ago as part of a more general post about making brake gear removable (Part 6a - Removable Brake Gear.) which is of course de rigour if you plan to be able to drop the wheel sets out of your chassis. Having explained myself once I’m not going to repeat it here, just follow the link if you’re interested. However, I do hope you spotted the nifty little adjusters I modelled as part of the outside pull rod and visible in the picture below.

You will note that one does have to leave a little more than the prototypical clearance between brake block and wheel. This is particularly true of locos fitted with suspension where the wheels move up and down relative to the brake hangers. Nor do the brake blocks pivot on the brake hanger to compensate, as they do in real life. Made of brass they are of course a short circuit hazard. Even if you go as far as making and fitting plastic brake blocks that do pivot, and I have done that, they produce enough drag to affect performance. As a result I’ve given up on that one and live with the fact that eliminating short circuits also means I have eliminated any undesirable braking effect on the wheels.

Nearly there

The one remaining item on the chassis structure was to fit the brackets which in theory support/reinforce the ends of the buffer beam. These are provided by the kit.

And that really is about it for the Chassis. The photo below is a repeat from the section on Removable Brake gear for those who didn’t feel the need to follow the link. On this occasion it is the J69 that is illustrated, and note that sand box.

Buck Bgear 4.jpg
Buck Bgear 4.jpg (257.85 KiB) Viewed 1599 times

There are of course a couple of things, missing from the wheels, and we’ll come to them next time.

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Wed Jun 17, 2020 5:59 pm

Part 16 - The Chassis Cosmetic Details 3

The Wheels


Missing from the wheels at this stage were not just the balance weights, but also the cosmetic axle centres which are part of the Exactoscale wheel system. I had not worried about either of these up to now as all the necessary bits were quite simple and supposed to be there, either as part of the wheels “package” or provided by the kits. Somehow, life is never quite that simple.

Balance weights.

The GER was very given to having standardised designs for bits of their locos, boilers for instance, and thus bits built into one class could show up on another as they passed through the melting pot which was Stratford Works. Considering that the wheels under the J65 and J69 are essentially the same 4’0” 10 spoke 10” throw design, they were clearly not that standard when you start considering the balance weights that were cast into them. The J65s cylinders had a shorter stroke, and hence a different crank axle, to those on the J66/7/8/9s, so the balance weights were bound to be a bit different.

None the less both kits came with etchings for balance weights which I just assumed would be a doddle to fit, so I didn’t worry about doing that till very late in the day. Well I won’t do that again. In future I will be sorting out the balance weights out right back at the very beginning. The two classes presented different problems.

By the way, if you happen across a picture of a Buckjumper with rather different wheels, you need to know that loco’s not intended for passenger work had totally different unbalanced wheels with lots more spokes.

J65

For some reason the GER fitted the first 10 built of these locos (including 155 my subject) with a balance weight design all of their very own. This dispensed with the traditional crescent shapes and add significantly to their character. The non-driven axles (front and back) had balance weights that totally in-filled the space between the spokes opposite the crank pin. On the driven centre axle, a square ended balance weight is fitted in the more usual place against the rim. This bridges three spokes, the ones either side of the crank pin and the one in advance. The second ten built had wheels with balance weights that looked much more like, but were smaller than, other Buckjumpers.

The snag came when I tried to apply the balance weights provided in the kit. Particularly those that were supposed to be applied between the spokes on the non-driven wheels. These may well have fitted on whatever wheels were available when the kits were designed. On the Exactoscale wheels they just dropped through the hole between the spokes. That said they were not far out, so I laminated them onto some scrap brass sheet and filed out slightly larger ones with a little lip (less than 0.5) all round. Particularly given the lip round the edge, these now fitted nicely and were superglued in place. The balance weights destined for the driven axle were also wrong in as far as they covered more than 3 spokes and one end were a strange shape, presumably to avoid the crank pin. Surprisingly, removing the extra odd shaped bit at one end and squaring up that end leaves a good representation of what should be there. Again these were superglued on.
buck j65 bweight.jpg
buck j65 bweight.jpg (268.17 KiB) Viewed 1280 times

Note that it was at this stage that the J65 became a 2-4-0.

J69

Again, the kit comes with a set of balance weights which didn’t satisfy. Those that were fitted to the prototype were really quite beefy, and those on the driven axle were particularly large, partly enclosing the crank pin. Those in the kit were distinctly anaemic by comparison. They did fit the wheel curvature, so I used one as a pattern for the curvature of the rim and filed up new ones which extended rather further round the wheels. That was fiddly, particularly where the driven axle ones fitted round the crankpin. As the wheels are lightly dished getting them to fit flat against the rim and the spokes wasn’t easy, particularly the big ones on the driven axle. They were again fitted with superglue.
buck j69 bweight.jpg
buck j69 bweight.jpg (331.42 KiB) Viewed 1280 times


In both cases, a close look would reveal that they were just thin overlays, so I filled in behind them with epoxy putty, which also helps to glue them rather more securely in place.

Axle ends

These are nice little disks of turned stainless steel which are supposed to be a good fit into the hole in the centre of each wheel that are visible in the picture at the end of the last posting. Unfortunately, this supposition was not borne out in reality. They were just a touch too big and no way could I get them to go in. Oh ***. I wasn’t at all sure how Exactoscale managed to get me into this position, but this appears to be a bit basic. I did wonder if I’d missed a trick of some sort and given the right approach they would happily pop in? Anybody else been here? The instructions (if you can find them, they are no longer available off the internet) are silent on this topic.

Anyway, in my world they were all accurately machined to 3.00 mm +- 0.01, and they weren’t going in unless they were no larger than 2.90, which isn’t much but apparently it was enough. Fortunately, they are turned with a step on the back which I could grip in a collet in the Dremel, and I was able to “turn” off the excess 0.01 against a file. They would then go in.

Once they are in, the question arises what you do if you ever want to get them out again. This you will need to do if you ever want to disassemble a wheel set again, after all one of the Exactoscale wheel advantages was/is supposed to be that multiple re-assemblies should be possible without them becoming loose on the axle. This all became that bit more pressing for me as it turns out that once you’ve turned enough off so that they will go in, they go in rather to far, and are not flush with the surface of the wheel as they should be. When I first put them in, I hadn’t worried about all this too much and I had been applying a light coat of water soluble PVA to ensure they stayed in place. Reviewed after the event, being recessed into the wheel just didn’t look right at all.

After an hour or so soaking in water, some could be popped out again, some couldn’t. As they have a small turned indent at the axle centre it proved possible to drill those that wouldn’t come out 0.5mm neatly in the centre. Once this hole was deep enough it gave a 0.5mm rod sufficient leverage to pop them out. When I finally put them in again, a small pad of blutack was used to ensure they stayed flush with the surface and they were all lightly drilled so they looked the same. I stuck with the PVA, as pressing on one edge should brake that bond quite easily, given the soft pad of blutack underneath.

Buck j69 wheel centres.jpg
Buck j69 wheel centres.jpg (188.35 KiB) Viewed 1281 times

This picture shows the starting position, with a couple of the end caps in view. The second shows the problem with the end cap deeply recessed and drilled so it can be removed. The third shows the hole packed with blutack, and the last has an end cap flush with the wheel face, as it should be but not yet drilled so it matches the rest.

Here ends work on the chassis.

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Buck Jumping on Mass - The Build Phase

Postby Will L » Sat Jun 27, 2020 11:52 pm

Part 16a – Getting the chassis going again

“Here ends work on the chassis” I said, and so I thought, after all it had been a running chassis for quite a while. However I decided I had better just retest it to ensure all was still well with the world. And it wasn’t.

First of all, one of the motor leads had broken off. My motor leads are always quite short and lead to a small two pin plug which connect it to the rest of the loco’s electronics. I use quite fine wire and handling had broken one off from the motor terminals. I remade it as in the photograph, reinforcing the solder joints with heat shrink sleeving.

buck 69 motor wire.jpg
buck 69 motor wire.jpg (93.54 KiB) Viewed 1122 times


Much worse was to follow, the motor ran but the wheels didn’t turn. It quickly became clear that I had a gearbox problem. It looked like one of the two idler gears in the Drivestretcher unit had lost a few teeth. This proved to be true as you can see from the gearwheels I eventually extracted from the gearbox. I suspect the missing teeth were stripped off against the brass final drive gear, but I’ve no memory of anything ever happening violent enough to do that. Fortunately, I had an unused gear box kit with two new gears the same size so I set about replacing both.

buck 69 gappy teath.jpg
buck 69 gappy teath.jpg (120.39 KiB) Viewed 1122 times


However, getting them out was easier said than done, and getting them back in again was worse. A picture follows which will help to explain what I mean. Remember that on a Highlevel gear box the intermediate gears all turn on fixed shafts. To release the 1st idler meant removing the shaft. This was easy to get at and it popped out no trouble. For neatness sake I have tended not to leave these shafts over length, but I did have an issue with a shaft dropping out in use, so I’ve started to leave them a little over length like this one. This gives the Loctite I use to keep them in, a bit more to work on. The 2nd idler shaft was not overlength, and unlike the 1st, it needed a brass bush glued to it to keep the idler gears aligned. It was also inside the wheels which made it hard to get at. Those with long memories will recall that one of the issues with Exactoscale wheels is that removing a wheel from an axle that is full of gearbox and axle blocks is difficult, if not impossible*, so I needed to find a way to get the shaft out without removing the wheels.
*(See Tom Millard’s article in MRJ 223 for the substantial brass jig you need to build to do it.)

buck 69 gearbox change.jpg
buck 69 gearbox change.jpg (302.3 KiB) Viewed 1122 times


It turned out that gluing the bush in place had also fixed the shaft very effectively to the gearbox frame. The wheels being in the way prevented any attempt to drift it out. In the end I attacked the shaft with a piercing saw close to one end. Once in two pieces it came out OK and I could then hit it hard enough to drift the brass bush off the shaft without difficulty. What I didn’t realise at the time was that, while the cut pieces could come out, there was insufficient room between wheels and gearbox to allow a new full-length shaft to be put back in! At the time this felt like a bit of a problem, so I slept on it and, as I have often found, the morning brought new insights.

The answer was to have a shaft made of two pieces, one quite short and the other as long as could be got in. These were jointed in a spare brass bush that I happened to have in among my Highlevel gearbox spares. The bush was fixed part way on to the short length of shaft, with Loctite 603, leaving a socket into which the second length of shaft could be glued in due course. This short shaft plus bush is put in the shaft hole on one gearbox site with a smidgen of fresh 603 in the socket. I had already checked that the two bushes together would ensure the idler gear would be in line with its partner. The longer shaft was threaded through the other gearbox side, the idler and the second bush threaded on and the shaft pushed into the socket. So long as the joint in the bush stays together all should be well, but just to make sure, 603 was smeared round the shaft ends outside the gearbox sides. The gearbox runs smoothly now. Let’s hope it stays that way. The picture shows the fixed gearbox with only the twin bushes to show what was done.

Hopefully, here ends work on the chassis… again

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Buck Jumping on Mass - The Build Phase

Postby Will L » Sat Jul 11, 2020 5:18 pm

Part 17 – Back to the Back of the body

Now the chassis is out the way, well apart from a little “Oh Poo” moment which got documented elsewhere, its back to the body work. You may remember we had assembled a very basic body shell with just enough of it there to ensure I could get the mechanisms in. It’s time to turn that into something recognisably Buckjumper like. We’ll start with the cab spectacle plates, and the bunker coal rails.

Spectacle Plates Front and Back

Stratford played about with their standard loco cab roof profile over the years, changing from a rather flat single ark wooden roof fitted in the early years to various versions of a significantly higher, compound ark metal roof. New locos got the higher roofs, and old ones were sometimes given the new profile when they passed through Stratford. Not all were converted and what dictated if a particular loco had its cab roof lifted or not I have no idea. Any loco so converted had a distinct and obvious banana (ok crescent) shaped addition to the top of the cab spectacle plate, and for tank loco’s like the buckjumpers, the cab back sheet too. However, this need not concern us here as both the chosen locos still had low roofs. This is just in case I ever decide to go backwards in time and think pre-grouping. Both kits support all the available roof shapes, so you need to select the right front and back cab sheet from the wide selection available.

On the original J65 kit the low roof cab front and back sheets had the windows etched in the wrong place, so corrected versions were provided as an additional etch. Some locos had ventilation holes drilled just under the roof line, some didn’t. these are half etched into the back of the cab sheets. Our J65 had them, so these holes were drilled out 0.5mm, the J69 didn’t.

There are various detail bits that need attaching to the front and back sheets and for me that means adding them before the main piece is are fitted to the loco. Chief among these on both kits were half etch window frame overlays to fit over the basic circular window opening, with and without anti-coal bars. The front ones were just a thin circle and were distinctly delicate, so cleaning off the attachment tabs while retaining the true circular shape was just a bit exciting. Those for the back had coal protection bars which did add a bit of rigidity.

I must admit that I had visions of these proving difficult to position and solder in the right place, particularly the very fragile front ones. However it turns out that if you get the spectacle plate hot enough for the solder to be liquid all the way round the window hole, surface tension will position them nicely for you, making a worrying job remarkably easy. Using 145° solder certainly helps here but you have to do these first as you need to get the whole thing really hot.

After the window frames are in place there is the typical GER ventilation grill to go on the middle top of the front sheet. Then the front and back sheets are fitted so they align with the top of the cab side sheets. This should leave the rear sheet sitting on the shelf formed to the rear of the cab interior. The pictures are of the J65 front and the J69 back, taken rather later in the build.
Buck cab plates.jpg


Coal Rails plus

The fully filled in coal rails were appropriate for both locos. To these were added the upright supports which the single layer etch didn’t represent. These do make fitting the coal rails to the cab sheets easier, but I will admit they are very difficult to spot once fitted. The lamp bracket fitted to the bunker back is made up from multiple metal strips as before, but only needs two strips in this case. The tails of these strips, once through the etched slot in the coal rails, neatly turn into the centre coal rail support.

A plate is supplied in both models to cap off the coal space just below the level of the shelf in the cab back. The J69 supplies inner support pieces to provide a ledge for this plate to sit on. The J65 didn’t, as it intended you to solder in this plate much earlier in the assembly process, presumably to keep the corners square, Those with a long memory may recall that, in part 12, I left it off, so supports to provide a ledge for it to sit on were fabricated from etch scrap. Both bunker capping plates need to be fettled to fit round those added upright supports for the coal rails. They now just rest in place on the ledges until such time as I coal the painted locos. This is so the space remains available to me for weight or possibly DDC chip fitting purposes. So they persistently fall out. The J65’s is now held in with masking tape, the J69’s I can’t currently find.

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Will L
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Buck Jumping on Mass - The Build Phase

Postby Will L » Mon Jul 20, 2020 10:47 am

Part 18 – Tanks for everything

Time to sort out the tanks both the tops and fronts. Way back in Part 10 I pointed out that the tank fronts in the kits were etched as a single peace the full width of the loco. This bears no relationship to how the prototype did it.

Buck J69 tank front before.jpg
Buck J69 tank front before.jpg (180.05 KiB) Viewed 762 times


I went along with it at that stage as it helped ensure the body went together nice and square, However even a cursory glance at any ¾ front view picture shows that the tanks had nice rectangular ends that enclosed the boiler but went no further inboard. The front plate was shaped to meet the boiler above the boiler centre but went straight down from there on to the footplate. Note the scrap etch strip fitted inside the tank front to form a ledge the tank tops could sit on. The excess bit across the front was cut away once the tank tops were fitted. As on the prototypes, the tank top pieces provided by the kits covered not only the tanks but also the gap between tank and boiler. To go with this, the tank fronts above the boiler centre line were extended in to meet the boiler.

Fitting the tank tops is the next job.

J65 Tank Tops

This is a simple job, the tank top etches just needs soldering into place butting up to the bottom edge of the cab sheet and just below the tank side top to form a lip. The white metal fittings (a tool box and the filler caps) will come later. The only additional work is to drill a hole in the footplate, just in front of the tank side. This takes the handrail on the tanks front edge which run up to a bracket included in the tank top etch

J69 Tank Tops

The J69 doesn’t have a handrail at the tank front, so we don’t have to do that, but there is a significant amount of other work was needed. The J69s intended for passenger work were originally fitted with condensing equipment to get them through the subterranean approaches to Liverpool Street. This includes a condensing chamber which sits on top of the water tanks, and which is concealed behind the upturn about ¼ of the way down the tank side which is such a distinctive feature of these locos. Many, including our subject 7054, had the condensing gear removed as years went by, but traces remained in the form of the condenser tanks. Once the basic tank top sheet has been soldered home there is an additional rectangular condenser tank applied on top. This tank has holes in it through which the condensing gear pipes used to go. The kit supplies etches of the patching pieces that were riveted over the holes. For reasons of their own, Stratford left the tank breather pipes in place. The ones provided in the kit were rather sad looking white metal approximations. I replaced these with lengths of the appropriate diameter brass tube, with a ring of fine brass wire soldered round the top and filed flat. (Filed flatter after viewing this photo!). A plug of thick brass wire at the bottom of the tube fitted into the hole etched in the condenser tank.



Buck J69 tank top detail.jpg
Buck J69 tank top detail.jpg (99.92 KiB) Viewed 762 times


Tank front corrections.

Once the tank tops were on, for both J65 and J69 a section of tank back, visible in those ¾ front views, was simulated by a strip of scrap etch about 8mm wide. This was soldered vertically from tank top to footplate and aligns to the very edge of the cut out for the boiler. Once these were fitted the bits of tank front and footplate across the middle and below the boiler centre line were cut away and filed flush with the new tank backs. The holes in the tank front will one day mount the Westinghouse pump and the handrails.

Buck J69 Tank front 1.jpg
Buck J69 Tank front 1.jpg (78.57 KiB) Viewed 762 times


Having got that far, next up is the boilers.

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Buck Jumping on Mass - The Build Phase

Postby Will L » Sat Jul 25, 2020 5:09 pm

Part 19– Boiler Basics

Essentially the same boiler was fitted to both the J65s and the J69s. There were detailed differences, some more invisible than others, in my case different safety valves, but both models started with the same size piece of brass tube, turned to give an accurate length and good square ends. The instructions for both kits talk about the need to trim away the bits of the tube hidden behind the tanks to clear the mechanism, but this had already been done on the boiler tube supplieds. Given my choice of motor and gearbox there seemed very little need to remove any more. As it turned out a few subtractions and additions were necessary, but we’ll come to that in time.
Buck boiler bare.jpg
Buck boiler bare.jpg (48.58 KiB) Viewed 344 times


Setting things out


The first job is to mark out the boiler top dead centre line. I don’t find marking out on curved surfaces very easy, but given one end was turned square, my trusty engineers set square was adequate for the job. The key thing is that the marked centre line does go straight down the boiler tube. This is definitely a measure three times mark once job. With so much of the boiler tube in the firebox/tank area already cut away, it was necessary to get the line more or less in the middle of the remaining tongue of metal. However, a few moments thought suggests it isn’t that critical (i.e. within ± 0.25mm will do fine)

Once the centre line is in place you mark out the position of at least, the chimney, dome, safety valves and boiler bands. You could add to that the clack valve locations as it is probably easier to drill the necessary holes earlier rather than later, but I didn’t. Drilling out the holes for the boiler fittings comes next. The boiler and dome were both lost wax castings with very solid posts to fit them on the boiler. This means drilling BIG holes in the tube. So I started small and worked up. This was hard work as frankly my modelling doesn’t normally need me to drill holes of that sort of size and I am not equipped. My “Kitchen table” has no pillar drill. Mr Rice’s instructions also advised drilling oversize so their exact position can be adjusted slightly when the time comes, which I think was good advice.

Make mine removable

The instructions, not to mention the kit design, assume that the boiler will be permanently fixed in place, but I would rather have sub-assemblies that can be painted separately. In the case of these locos I was aiming to keep the boiler assemblies separate from the rest of the body. My plan was that the cab end would sit on a lip soldered to the cab front, the length of the boiler inside the tanks would fit snuggly under the tank tops and the smokebox end would sit on the footplate and be bolted down from underneath. On the J69 but not the J65 (see Part 9 - The body is a foot... plate), there is already a fixed nut on the footplate in the smokebox saddle area which is the chassis mounting point. I did wonder about making the one bolt do two jobs but in the end I decided against. As the saddle was too shallow to accommodate the soldered on nut, it was necessary to remove metal from the boiler tube so it cleared the fixed nut.

Here is a picture of the J69 boiler taken a bit further down the line. There is quite a bit of explaining to do before we get here, but it does show where I’m going with this.

Buck J69 Bolier basics.jpg
Buck J69 Bolier basics.jpg (69.23 KiB) Viewed 344 times


Next time we will move on to forming the smokebox.

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Buck Jumping on Mass - The Build Phase

Postby Will L » Thu Jul 30, 2020 12:12 pm

Part 20 – Smokebox bending

This job is pretty much the same for both J65 and J69 and the photos are a mixture of both.

Smokebox Wrappers 1 & 2

The smokeboxes are made up of three layers of overlay each one with the hole for the chimney etched in. The first two just wrap round the boiler tube. Do them one at a time. Forget rolling bars, anneal it if you must, then bend it round the boiler tube. Neither the first or second wrapper will quite meet underneath but nobody will ever know. To make sure each of these first two wrappers are firmly in place, I made up a clamping device from scrap etch and an engineers clamp. This held each wrapper tightly in place while I soldered round the edges with lots of liquid flux a nice big hot bit and 145° solder.
Buck Boiler clamp.jpg
Buck Boiler clamp.jpg (125.25 KiB) Viewed 220 times

Note that, unlike the advice often seen, I don’t tin the back of overlays of this sort.
1. I find the layer of solder just gets in the way of getting the overlay to lie flat on the surface beneath,
2. getting enough heat in to the joint to get the solder liquid over the entire overlay is near impossible and if you don’t you are likely to get problems with differential expansion, and,
3. in any event, just soldering the edges seems to produce quite solid enough a job.

Illustrated is the J69 boiler, so you can see the bit taken out to clear the captive chassis mounting nut on the footplate. Once both the first two wrappers were in place, I removed the metal that overlaps the cut away. Hindsight also suggests that a smart move would have been to grind away a small slot in those two wrappers in front of the chimney hole. This is to accommodate the tail of the lamp bracket that will be fitted there in due course. I certainly will next time I get to this stage.

The Smokebox Front and Saddle

In the background of the picture above you can see the third wrapper. This also forms the sides of the smokebox saddle and so demands a different approach. The rear side of the J69 saddle which goes with it is also in the picture. Provision for a visibly riveted smokebox is made in both kits in the form of half etch push through rivets. However this is a late LNER/BR feature and both mine had flush head rivets and were smooth, so you just use the other side of the wrapper. Both kits use an etched smokebox front sheet which includes the front profile of the smokebox saddle. While, as we saw above, on the J69 the rear piece of the saddle is a separate etch, on the J65 it is a bend up part of the footplate.
buck j65 orginal sadle.jpg
buck j65 orginal sadle.jpg (55.2 KiB) Viewed 220 times

Given my intention for the boiler to be removable, this piece has to be detached from the footplate. Given there was very little metal in the middle trying to remove it produce two separate halves which makes final assembly just that bit more fiddly.

Before dealing with the third wrapper, it is time to attach the smokebox front plate. This is going to be soldered to the front of the boiler tube + first two wrappers assembly, so that needs cleaning up and filing smooth first. Of course, it is necessary that the top dead centre of both boiler and smokebox front are well aligned. Another of those check three times do once moments. Done correctly the front plate will overlap all round the two wrappers leaving a lip the remaining overlay will butt up against, so any excess solder needs to be carefully removed.

Wrapper 3

You might choose to anneal this wrapper too, but, given it ends up being the only thickness of metal on the smokebox saddle sides I chose not to. Note that this wrapper is not as wide as the previous two as it is designed to leave a prototypical step on the back edged of the smokebox. For this reason, the hole for the chimney isn’t on the centre line on this wrapper as it was on the others, so you have to get it the right way round.

I started out by bending the wrapper round the smokebox top and tacking it on at the top dead centre, front and rear. Then I bent one side round the smoke box until I got to the place where it bends away to form the saddle. I formed this bend around a medium size jewellers screwdriver, which seemed to be about the right size, until it was a good match with the front plate. I tacked the wrapper to the boiler again just above the bend to form the saddle, and repeated myself on the other side. Once I was happy everything was going to end up in the right place, I ran the solder joints between the, now, 3 tacks, then finished the job to the bottom of the saddle, reinforcing the joints in the saddle with strips of scrap etch. Finally I fitted the back profile piece(s) for the saddle, similarly reinforced.
Buck boiler sm done J65.jpg
Buck boiler sm done J65.jpg (140.57 KiB) Viewed 220 times

Finally I cleaned up the joint between the third wrapper and the front plate to give nice square corners. As this photo of the J65 boiler shows, this all worked out well. Round the top of the smokebox, it is actually very hard to see the joint between the third wrapper and the front sheet. As I didn’t write this until a significant time after I did the job, I had to look very hard to see exactly how I’d done it. The joints around the smokebox saddle aren’t quite as good so gave the game away, but, as they will end up being hidden behind the front sandboxes, perfection, while desirable, isn’t all that necessary.

And that’s the basic boiler done. Note those great big holes for the boiler fittings, particularly the one for the dome. Note also the small slot in the smokebox face which is intended to take the lamp bracket I mentioned above. I have a thing about getting lamp brackets solidly fixed to locos, thus I ended up laboriously chain drilling and scraping out the metal behind that slot so I could get a decent depth to secure the tag end of the lamp bracket. I had to do this twice, once per loco remember, and it’s not a nice job. If I’d made that slot in wrappers 1 and 2 when I put them on, life would have been much easier. I still have to drill again for the handrail knob which goes top dead centre beneath the lamp bracket, but at least that is a nice round hole.

Now we have the basic boilers, fitting them to the rest of the body comes next.

RC38427

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Will L
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Re: Buck Jumping on Mass

Postby Will L » Thu Jul 30, 2020 12:21 pm

Those of you who are following the Language thread will note that I favour "smokebox" as all one word. In MS Word where, I write most of this stuff, accepts this but the spell checker in my browser, Firefox, doesn't. I also believe "hornblock" to be all one word, regardless of what you think its made up of.

I am unrepentant.

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Re: Buck Jumping on Mass

Postby grovenor-2685 » Thu Jul 30, 2020 12:59 pm

Regards
Keith
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