Crab Comet conversion

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Jol Wilkinson
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Re: Crab Comet conversion

Postby Jol Wilkinson » Tue Mar 19, 2019 7:55 am

A little late to the conversation but does anyone else find that the loose fit of the crankpin bush on a AGW (or even Sharman Wheels if you still have any) can cause a problem.

Loco "chassis" that will can be propelled or run smoothly when the crankpin nuts are loose sometimes develop a tight spot when the nuts are tightened. Loosened off, wheels rotated a quarter turn or so, or rocked back and forth and re-tightened and the problem may be cured. I should add that I use a GW quartering jig and LRM alignment jigs for setting up, having assembled the rods and broached them for a close fit on the crankpin bushes. However, there is more play between the crankpin and the bush than the crankpin and the rod. Opening up the coupling rod crankpin holes is usually the solution, but not an ideal solution. I wonder also if the bush holes are sufficiently concentric, especially on the brass Sharman ones.

I can always get over the problem but it usually takes a little time even with four coupled locos. So getting a consistent and close "fit" of the rods, pins and bushes seems a bit of pot luck. A threaded, concentric, bush which fits on the pin accurately would seem to be the answer.

I should add that I have never used Ultrascale or Exactoscale loco wheels as there is nothing in either range that suits LNWR locos, AFAIK.

Dave Holt
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Re: Crab Comet conversion

Postby Dave Holt » Tue Mar 19, 2019 10:27 am

Jol,
I experienced the exact same problem with my first two locos. They would run sweetly, then after disassembly and reassembly, during construction, they would bind and limp along. The loose fitting AG bushes were determined to be the problem. This appeared to be made worse if the bush was shortened to suit the thickness of the rods.
The late John Hayes suggested changing to Ultrascale crank pin bushes, which he considered to be a better fit on the screws. I did so and solved the problem immediately. Of course, as discussed earlier in the thread, I don't use the Ultrascale bushes in the way intended but still get satisfactory and, importantly, consistent results.
Dave.

Dave Holt
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Re: Crab Comet conversion

Postby Dave Holt » Tue Mar 19, 2019 10:42 am

Will L wrote: I doubt that the complexity of load bearing pony truck will repay the complexity they introduce with any visible improvement in the running properties of the loco, CSB fitted or otherwise.


Will,
We clearly have differing views on this and that's fine. The key thing is to have satisfactorily running locos, whatever the design features.
However, I'm not sure how having a pony truck sliding on bearing pads, with the axle sprung within the truck with simple wire springs, can be considered to add "complexity" compared to, say, working outside valve gear or detachable keeper plates, etc.
I admit that those of my locos that have the pony truck or bogie axles as part of the compensation, whilst leaving their frames unloaded (as per prototype) is more complex than the simple springing arrangement discussed earlier, I don't find it to be an especially difficult problem and enjoy the satisfaction of finding a practical way of implementing the arrangement.
Dave.

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Jol Wilkinson
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Re: Crab Comet conversion

Postby Jol Wilkinson » Tue Mar 19, 2019 11:44 am

Dave Holt wrote:Jol,
I experienced the exact same problem with my first two locos. They would run sweetly, then after disassembly and reassembly, during construction, they would bind and limp along. The loose fitting AG bushes were determined to be the problem. This appeared to be made worse if the bush was shortened to suit the thickness of the rods.
The late John Hayes suggested changing to Ultrascale crank pin bushes, which he considered to be a better fit on the screws. I did so and solved the problem immediately. Of course, as discussed earlier in the thread, I don't use the Ultrascale bushes in the way intended but still get satisfactory and, importantly, consistent results.
Dave.


Dave,

good to know I am not alone!

All my six kits in the stash all have Sharman wheels in the boxes, the only correct versions once available. These have the crankpins moulded in, so the wheels can't be counter bored to take the Ultrascale "crank pin tube" but I wonder if it would still worth trying their bushes. It is not clear from their site whether the long or short bushes would suit. They are all inside cylinder locos.

Jol

Dave Holt
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Re: Crab Comet conversion

Postby Dave Holt » Tue Mar 19, 2019 2:43 pm

Jol Wilkinson wrote:It is not clear from their site whether the long or short bushes would suit. They are all inside cylinder locos.

Jol


Jol,
The short bushes are 1.25 mm long on the bearing surface. That should be plenty just for coupling rods. I've explained earlier in the thread how I use these on unmodified Gibson wheel by soldering on the rear washer (which fits over the reduced diameter portion) and filing flush at the back, so the same approach should work on Sharmans, with moulded in crank pins.
Dave.

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Will L
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Re: Crab Comet conversion

Postby Will L » Tue Mar 19, 2019 5:29 pm

Dave Holt wrote:We clearly have differing views on this and that's fine. The key thing is to have satisfactorily running locos, whatever the design features.
Dave
Can't argue with that.
However, I'm not sure how having a pony truck sliding on bearing pads, with the axle sprung within the truck with simple wire springs, can be considered to add "complexity" compared to, say, working outside valve gear or detachable keeper plates, etc.
The comparison is with a non load bearing pony truck surely and they do tend to simplicity. Not sure how unavoidable issues like outside valve gear got into this, but I cant resist pointing out that basis CSB methodology means you don't need detachable keeper plates.

There is no doubt that a tried and tested technique you're familiar with will always be the easiest and best way forward, although others may not find it so easy to achieve. If I wanted to do a load bearing pony truck on a compensated (like Julian) or rigid chassis I suspect your methods would be a good way to go. On a CSB however having gone to the trouble to calculate out a balanced set of the axle loads, fitting another set of load bearing springs does rather negate the effort so far, and leads me to find and prefer another solution which I find easy to achieve.
I admit that those of my locos that have the pony truck or bogie axles as part of the compensation, whilst leaving their frames unloaded (as per prototype) is more complex than the simple springing arrangement discussed earlier, I don't find it to be an especially difficult problem and enjoy the satisfaction of finding a practical way of implementing the arrangement.

I do agree that finding solutions that work for you can be very much part of the fun, which takes us back to Julians thread, hopefully.

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Jol Wilkinson
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Re: Crab Comet conversion

Postby Jol Wilkinson » Tue Mar 19, 2019 6:02 pm

Thanks Dave,

I've ordered some to try out.

Odd that they don't give that information on their website, or at least I couldn't find it.

Jol

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grovenor-2685
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Re: Crab Comet conversion

Postby grovenor-2685 » Tue Mar 19, 2019 10:15 pm

A related topic on RMweb came up with this source for screws 1mm at 10mm length, packs of 100 at a very reasonable price.
https://www.ebay.co.uk/itm/M1-M1-2-M1-6-M2-M2-5-A2-STAINLESS-MACHINE-SCREWS-CSK-COUNTERSUNK-SLOTTED-BOLTS/191481004526?hash=item2c952841ee:m:m9CPBayODBxwvCaSOm9QZMQ
regards

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Wed Mar 20, 2019 6:59 pm

Jol Wilkinson wrote:. A threaded, concentric, bush which fits on the pin accurately would seem to be the answer. .

(ReGibson bushes)

If the long bush was available threaded it would give a better return crank fixing too. My thoughts have idled over the practicality (or otherwise....?!) of finding suitable brass tube, soldering it in (a long bush) and then drill and tap 1M...

Re the Ultrascale system in general, I suppose the chance of getting properly perpendicular cranks is much higher. I find that is a bit chancy with the AGW system however careful I try to be. (Edit - Philip has already mentioned this plus solution)

Edit

I've removed a stupid question from here.
Last edited by Julian Roberts on Wed Mar 20, 2019 9:30 pm, edited 1 time in total.

davebradwell
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Re: Crab Comet conversion

Postby davebradwell » Wed Mar 20, 2019 8:40 pm

Julian,

Weren't the Exactoscale crankpins - shortly to be re-introduced - tapped? I can't remember with 100% certainty but there was a flanged base. They might be just the ticket.

DaveB

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Thu Mar 21, 2019 8:12 am

Thanks DaveB - but are Exactoscale tapped 1M? No information available on their current website.

By the way I didn't answer - the Bachmann fallplate does its job getting in the way in a devilish manner if I couple the tender and loco not quite correctly. But done correctly it is fine.

And regarding something else you said,
You'd end up with a sort of Crampton, with a rigid bit at the back and the front propped up on 4 springs. Strange but not unsound

it is rigid at the front as the two 30g Exactoscale springs in the pony truck do nothing. The loco is approx 400g, CofG approx halfway, so the pony is bearing 200g minus whatever force the front drivers are putting down. Weird, I agree!

Dave Holt
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Re: Crab Comet conversion

Postby Dave Holt » Thu Mar 21, 2019 9:12 pm

[quote="Julian Roberts"]
Re the Ultrascale system in general, I suppose the chance of getting properly perpendicular cranks is much higher. I find that is a bit chancy with the AGW system however careful I try to be. (Edit - Philip has already mentioned this plus solution)

Julian,
Sorry if Philip has already mentioned this method which I picked up from somewhere (certainly not my idea, might have been the CLAG site) to help get the crank pin screws perpendicular in Gibson wheels by using an inverted long Gibson bush with the flange held hard against the wheel boss by pliers whilst the screw is slid down the bore and screwed into the plastic. Obviously, the screw has to be taken out again to release the bush, but with care the newly created thread in the wheel can be picked up again. It certainly seems to help eliminate wonky crank pin screws.
If you have access to a lathe, a custom made version, pehaps with a wider flange, cut away to clear the central, raised rear boss, could easily be made.
Dave.

Philip Hall
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Re: Crab Comet conversion

Postby Philip Hall » Thu Mar 21, 2019 9:52 pm

I haven’t heard of that idea, Dave, but it seems very good. I must try it sometime, but in practice I usually bend them straight again! Where the idea might not help is where the hole in the wheel is not perpendicular, and Chris Pendlenton highlighted this in his MRJ article. Then either drilling out, plugging and redrilling, or just bending straight, would seem to be the only option.

Philip

davebradwell
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Re: Crab Comet conversion

Postby davebradwell » Fri Mar 22, 2019 10:30 am

We seem to have abandoned Julian here but, anyway, where I have used Gibson crankpins (usually on inside cylinder engines) I have reasoned, like you Dave, that the crankpin hole on the outer front face is probably more accurate than the rear. Further, I have never understood why the wheel has to have a thread so have drilled the hole 0.95 diameter in a machine from the front which isn't quite a clearance. Screw will now follow hole rather than going in its own direction. Face of wheel should be cleaned up where the flange rests.

I use a drill jig for the Ultrascale counterbores to ensure consistency. Of course for outside cylinder engines, the boss must be reduced until it is flush with the tyre. This is clear on GA drgs and gives a bit more or even some clearance behind the crosshead or conn rod if the crosshead is slightly forward.

This extra care is needed because I have quite randomly decided that the usual "next drill size up" for the coupling rod holes feels terrible and may well contribute to uneven motion. As a result there is only a couple of thou' to play with on the whole assembly and I need to knock out as many variables as possible. We can't reliably measure to within the odd thou' or so without rather better equipment than is usually around so good practice is essential.

DaveB

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Fri Mar 22, 2019 3:27 pm

No problem DaveB!

On with the job, with a couple of hours to get on. The LHS gear was shown working about a year ago but I've had trouble on reassembly. Now I seem to have found the return crank can be secure if it is wound on two full turns so the long bush has been shortened so that the crank tightens down on it at exactly the right orientation. This takes it very close to the connecting rod so the issue becomes that I don't want any trace of the back of the rivet on the crank to be there at all. So I've removed the rivet and replaced with another, this time soldered so that it can be filed flush with the back of the return crank. At the same time I've built up the front of the crank as per the prototype with a rather nice 0.8mm washer from Prime Miniatures. (I bought nuts bolts washers for fixing the valve gear later, more easily available than 16BA.) While at it I did what I should have done long ago and beefed up the eccentric rod with some 0.33 piano wire. It is horribly flexible without some backing. Same with the radius rod. Now another layer was needed to separate the crank from rod so the end of the superfluous mystery part 35 was just the job. A long rivet was soldered to the crank and filed down.

A 14BA spacing washer will separate the con rod from the crank by the minute amount needed. Writing this now on bus to work I just hope I've got it all the right way round....!
Attachments
20190322_111437.jpg
Crank clears rod
20190322_101255.jpg
Crank built up
20190322_095456.jpg
Piano wire added to rod
Last edited by Julian Roberts on Mon Mar 25, 2019 6:26 am, edited 1 time in total.

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grovenor-2685
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Re: Crab Comet conversion

Postby grovenor-2685 » Fri Mar 22, 2019 5:25 pm

grovenor-2685 wrote:A related topic on RMweb came up with this source for screws 1mm at 10mm length, packs of 100 at a very reasonable price.
https://www.ebay.co.uk/itm/M1-M1-2-M1-6-M2-M2-5-A2-STAINLESS-MACHINE-SCREWS-CSK-COUNTERSUNK-SLOTTED-BOLTS/191481004526?hash=item2c952841ee:m:m9CPBayODBxwvCaSOm9QZMQ
regards

I ordered a 100 of these (1 mm x 10 mm) on Tuesday, arrived in todays post.
Regards

Dave Holt
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Re: Crab Comet conversion

Postby Dave Holt » Fri Mar 22, 2019 8:35 pm

[quote="Julian Roberts"]

so the end of the superfluous mystery part 35 was just the job.

Ah, yes! The mysterious parts 35. Superfluous, as you say. I think parts 35 are the counterbalance arms fitted to the reversing wey-shaft, between the frames of the prototypes. They show up on the the LMS GA and valve gear drawings in the exact same orientation as shown on the Comet valve gear sketches. I assume that whoever drew up the etch drawings for the model didn't realise they are hidden from view between the frames?
Dave.

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Sat Mar 23, 2019 9:17 am

Aha Dave, at last the answer to my opening post question 18 months ago, thanks to you! I'm glad it's not only this musician who can't read a GA drawing (and that even professionals can make mistakes). Any more than the average person who likes listening to music will be much enlightened looking at a full score. Here is a snip (so I hope this isn't a breach of copyright or trust) of the relevant bit of the drawing, that may be getting a bit faint. What is the code by which one is to know the "Part 35" is hidden behind the frame I wonder?
Attachments
Capture GA Crab.PNG
Capture GA Crab.PNG (81.11 KiB) Viewed 2310 times

davebradwell
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Re: Crab Comet conversion

Postby davebradwell » Sat Mar 23, 2019 12:11 pm

You've done a fine job, Julian, for getting the bits together and working - I would have expected the design to include reference to spacing washers if these were required to get the bits to miss each other. It just shows how much knowledge the builder is assumed to possess. On the other hand with parts intended for use in all 3 gauges and different wheels there are a lot of combinations to cover.

Now we have the dangers of GA drawings which were only ever intended to show how the pile of bits fits together. Your mysterious bit might well have appeared on the plan view but these were usually half top/half bottom so things occasionally never show. You'd probably have to find it by elimination. Cross sections are often on another sheet which is less readily available. Another trick with GAs is when a part, which will be defined on its own drawing, is changed and the GA may be left unaltered.

DaveB

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Sun Mar 24, 2019 8:20 am

Dave B thank you!...I've only myself to blame for many of the issues I'm writing up here (as a blog of one step up two steps down which is the case with all the locos I've made). I've "freelanced" so much it is a long time since I looked at the instructions! Certainly there's nothing about beefing up these vulnerable rods there. They are fairly brief but certainly adequate except for a very beginner who would be unlikely to be tackling this. The etches are really good - lovely motion and valve gear that is not overscale (which is so often the case); lots of washers, some half thickness so very useful. I think the kit is great value, but you'll see why I'd like to get one of yours.

Thanks to all for the great ideas on crankpin insertion into wheels.

Next step is the 14BA washer that sits in the connecting rod - it's broached out to slip round the bush. That sort of thing is easier now with some new broaches! - and parallel pliers to hold the washer. Then slimmed down from 0.37-ish to 0.27-ish. Then make another one when the first one's lost...and then (see later) find it may have been a waste of time.

20190323_101514-1 (Small).jpg
Top left is the dieblock. Only enough meat for a 16BA or 0.8mm bolt
20190323_101514-1 (Small).jpg (39.39 KiB) Viewed 2225 times


I've settled back on Peco pins to hold the reversing links, which was why I put the reversing shaft linking each side as per the real thing in the first place. They will be slightly bent to grip inside the reversing shaft tube (and shortened so that there's room for them both) as per the pins holding on the brake gear aka pickups - so easily removed.

The final bit of the construction was adding the link from the reverser. This goes behind the sandbox on the real thing so is truncated at that point here. Now I know parts 35 are supposed to attach to the reversing shaft between the frames but I can resist the temptation to put them there. :shock:

20190323_115102-1 (Small).jpg
Attaching the tiny reverser link. This photo shows the two layers of the dieblock
20190323_115102-1 (Small).jpg (38.75 KiB) Viewed 2226 times

20190323_115239-1-1 (Small).jpg
completed. All the crud that I haven't cleaned off as I go is looking quite a good basis of the real crud I want to be modelled!
20190323_115239-1-1 (Small).jpg (55.06 KiB) Viewed 2225 times


Real engineers had probably better skip the next bit (though they're probably not on any thread of mine in the first place).

Now the moment of truth - can I get my new HSS tap (0.8mm rather than 16BA which I couldn't obtain) to tap through the dieblock? Following lots of helpful hints by you great folks on the Forum (see viewtopic.php?f=7&t=5866&p=60897#p60897) I bit the bullet...the worst thing would be to break the tap half way through the job and have it stuck in there! - so it was a case of being very careful.

For whatever various reasons it was already drilled (by me) a nominal 0.75 - actually 0.72. The tap was 0.8 to 0.82-ish area, and the nominally 0.8 bolt was 0.77 or so. (All measurements by my trusty cheapo digital micrometer! - so not necessarily dead accurate.) Very carefully I tapped just holding it with finger and thumb, a quarter turn at a time, lubricated with 3 in 1. It would not go fully right through the two layers of the dieblock that sandwich the expansion link as it was not long enough, but it was sufficient for the bolt actually to actually screw right through. Jings! - as they say up here. By the way for those that questioned why I needed 16BA, I reckoned the dieblock was too fine to be able to accomodate a 14BA set up, as was the expansion link itself, thus my choice of 16BA, or now 0.8mm. A 14BA countersunk screw might not have sat proud of the dieblock. Countersunk 0.8mm does not seem to be an option.

So the gear is attached in five places - the valve rod has to be slipped in first, 16BA nut on the crosshead, the reversing link (Peco pin), this dieblock, and the return crank.

20190323_165055-1 (Small).jpg
How I want it to look...but I've got to get the return crank fixing sorted out still.
20190323_165055-1 (Small).jpg (52.17 KiB) Viewed 2226 times


Well that was all very nice but then I wasted a good two hours on the return crank again and the fact is I'll have to have a rethink. I can't get the thing to screw down as the threads must be too worn as I have said previously.

Options seem to me to be:
1. unsolder the Gibson retaining thingy from the return crank (without undoing the work I did on Friday!) and solder in a new one but I'm sceptical even if it worked that this will be a long term solution and may fail a few years down the line when I've totally forgotten what the issues are.
2. Get 14BA screws/bolts/crankpins into the wheels so I can use the Ultrascale recessed crankpin bush/retainer. The present crankpins are fixed in with Loctite 601 so I'm not optimistic I can get them out and have to contemplate getting a pair of new wheels so I can use the Ultrascale system all the way through for this middle wheelset. This latter is the best solution but the thought is a bit hard to swallow at this advanced stage.
3. Somehow make the equivalent of the Ultrascale recessed retainer with 1M thread. To buy a tap is the easy bit. The Gibson long bush just needs to be a threaded fix to work a treat. Occurs to me I could fill it up with solder, drill and tap, as the thread isn't under much mechanical load once it's bunged up with glue. Hmm... a bit difficult while already attached to the valve gear as it would have to be. The ideal thing would be if Colin produced this...
(Next day)
4. Solder the crank to the crankpin. This will be fine but probably a once only solution, negating the idea of having everything dis-assemblable.
5. I have just the right tubing, OD 1.5mm, ID 0.5mm, to make equivalent of the Ultrascale recessed thingys. It's a question of the difficulty of soldering this on perpendicularly to the return crank. It's either that, having a go, or admit failure and start over again with a pair of new wheels. Having a go is more appealing. The cost of buying a 1M tap (£13 or £5 for a Chinese one from CousinsUK https://www.cousinsuk.com/product/taps-by-size-metric) is more than buying a new pair of wheels (in fact new wheel centres are all that I need and Colin does that for a nominal charge I believe) but is an investment worth making.

Yesterday the chassis was disassembled for painting. The 1st stage of the gearbox was easily removed with nail varnish remover. Nitromors will be obtained to remove the worm (glued on with 24hr Araldite) from the motor, for replacement with the 1:120 gearing. If there's any problem luckily I have another motor exactly the same size.

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Tue Mar 26, 2019 4:24 pm

( I edited and extended my previous post)

Disassembled, the chassis gives me cylinders more easily worked on to do the drain cocks. Thanks again to Dave for the idea of the Brassmasters detailing kit, I read the online instructions which say Scottish engines had shrouds around the valves, and that many had the pipes shortened. Looking through my photos of ScR locos I can't see any with pipes extending to the footsteps, though none of the photos show the area at all clearly. I can't see what is meant by shrouds in any photos, though David Franks' loco shown earlier looks different here and that must be correct, knowing him! £25 for the detailing kit would be OK if I wanted the rest of it, but some of the things (e.g. balance weights) are already in this Comet kit, and the rest (e.g. metal footsteps) I am not very bothered with. So, after looking carefully at the Bachmann offering which is meant to be added to their loco, and looks a very nice representation of Keith's photo, I opted to try and replicate that rather than actually use it with the difficulty of attaching pipes securely enough. I've ended up soldering some .33 wire into a short Gibson handrail knob, cutting off that wire on one side of the knob, shortening the knob where it should fix into the boiler, and soldering that between the castings on the Comet cylinders, for each pipe. A bit of .45 wire was easily soldered into the cylinders near the front to act as a fixing bracket. The third wire just goes straight into the cylinders behind. Not exactly correct but "near enough for jazz" as we used to say when I was a student. A piece of 0.6 wire represents the lever that is behind. By the time I did the RH cylinder I realised .33 wire was a bit thin and used .45 for the front two. Final trim to length will be later.

A new tin of Nitromors doesn't seem to do anything to loosen the worm from motor shaft that was fixed with Araldite. I have a loco to make with smaller wheels if this motor can't be parted from its gear ratio.
Attachments
20190326_113939.jpg
20190326_113459.jpg
20190326_134941.jpg

jasp
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Re: Crab Comet conversion

Postby jasp » Tue Mar 26, 2019 6:17 pm

Julian
Often heating the part(s) with a soldering iron will destroy an epoxy joint
Jim P

davebradwell
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Re: Crab Comet conversion

Postby davebradwell » Wed Mar 27, 2019 9:39 am

Julian, just spotted something in your recent description of adjustments - is it too late to talk you out of 120:1? Most of my main line engines have 30:1! You'll need ear protection if it's used on a passenger train.

DaveB

Julian Roberts
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Re: Crab Comet conversion

Postby Julian Roberts » Wed Mar 27, 2019 9:36 pm

Jim thanks. I'll report on any progress.

Dave thanks for your suggestion but I hope you wont mind if I hopefully politely disagree as I did with Allan last page. I've made plenty of locos now that prove noise is no issue. They are all either 80:1 or 108:1. The layouts they are for have a maximum realistic scale speed of 30mph, and so do the locos. Mostly the interest is shunting and manoeuvring. In an exhibition there is plenty of conversation noise and that is the only use they have. I'm not interested in making them go faster.

I'm more switched into movement than appearance. After my number one hatred of derailments my second hate is unrealistic slow speed running. Seldom do we see the huge momentum of the real thing modelled in realistic starts, stops, braking , acceleration - even on visually perfect setups.

4 hours got me what I could christen the "Roberts Retainer". Very fortunately I found some top hat shaped bushes just perfect for a force fit of the tubing, soldered just to lock. The 1M tapping took 2 hours, made bearable listening to MPs finally let off the leash. The technique I finally arrived at was to drill it nominally .85 (actually. 82) rather than the official .75 (actually .72). Hold the Roberts Retainer securely in a drill and turn the tap one bit a time with the parallel pliers. Hopefully the 2nd one should be a lot quicker. Then it's just a matter of soldering them to the return cranks.

The frames are going a peculiar colour soaked in various thinners and now vinegar. 18 months of no cleaning is proving a challenge.
Attachments
20190327_125348.jpg
20190327_211334.jpg
20190327_211217.jpg
That retainer took 4 hours
20190327_211554.jpg

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Allan Goodwillie
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Re: Crab Comet conversion

Postby Allan Goodwillie » Sat Mar 30, 2019 8:38 am

Still following your thread Julian, :)

Something no-one has remarked upon is the sense of robustness and weight that seemed very evident on the real thing is being translated into the model and that the little extras you are doing are adding to this nicely. I do agree with what you have said about the locomotives being built for a particular style of layout and even when I get Grayrigg back into operation I will expect to see it working steadily up the gradient with something unfitted or semi-fitted. Looking forward to seeing it passing by with a long train behind it. The huge cylinders putting in a massive effort. The real things were always memorable to watch. I have many memories of seeing them on the Carlisle freight avoiding lines.

I have rebuilt the tender drive WD recently into a conventional loco drive and it is much quieter now, but the tender drive seemed to amplify the sound of the gears and although it gave slow running I did not like the noise level, particularly evident with the layout at eye level and when the locomotive was working flat out with a long train.

May have to shave another bit from the platform at Grayrigg to allow the cylinders to pass - the WD Cylinders required a smidgeon off despite setting everything to the S4 clearances guide! So a trial session may be required.

Allan :)


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