Livingston - West Lothian Starters Group

Help and advice for those starting in, or converting to P4 standards. A place to share modelling as a beginner in P4.
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Allan Goodwillie
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 8:19 am

I will not go into the same level of detail with the construction of the second gearbox by Comet, which is of a similar design to the Markits option, however, I will try to point out differences where they are relevant.

The outside information on the packaging is minimal but, most of the important info is there or can be made out. Nothing shows through the packing, so what does it tell us?

It is a two stage gearbox - so a layshaft and gear being used similar as it happens to the Markits one we have been looking at
The reduction or ratio is 50:1
It includes precision cut helical gears and a steel worm with grubscrew (presumably the other gears are Brass)
It has 8mm or 10mm fixing holes for motors such as the DS10 (you will need to have knowledge of what the fixing points are on the motor you are intending to use)
The small sticker with 2.0 marked on it refers to the shaft diameter of the motor required, so the level of information is about the same on the packaging.


Looking at the diagram which also forms the instructions, we can see immediately that there are several features that are different.

The first is that unlike the Markits gearbox there are no side lugs as alternative fixing points for the motor, so it can only be attached via the holes in the back of the gearbox. This can be awkward when dismantling as it is tricky to get the second screw out once the other gears are in position - we will come back to that.

Something again that is different but, perhaps, not so obvious is that the final drive is more directly below the layshaft in the gearbox. The Markits final gear is much more forward and there is a shape cut from the box itself to allow the bottom gear to get into more awkward positions -e.g. the rear driving wheel of locomotive under the cab. So perhaps the Comet one suits a central drive better than below the cab, but it depends on the loco.

There is no side access to uncouple the worm or to adjust the position of the wormscrew, adjustment requires unscrewing the motor and taking out the worm and motor to do it.

Usefully the diagram shows the "Handed" nature of the front plate and explains the use of the two holes that are in it. No front bearing for the motor is provided however, and in my case I will be cutting this part away to allow me access to the small screws that will hold the motor on. Other snippets of constructional information help to guide the novice when putting the gearbox together.


Julian Roberts
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Re: Livingston - West Lothian Starters Group

Postby Julian Roberts » Sat Aug 06, 2016 7:50 pm

Hi Allan

As I was starting only nine years ago in P4 I hope you won't mind me contributing some extra things I recall:

The spacer width is fundamental to how sharp the minimum radius the finished loco will take. You have mentioned this. But it was quite a lesson to me: on my first loco (an 0-4-4) I took on trust the P4 spacer manufactured by the same maker as the kit, but I ended up with not enough sideplay. I didn't realize until I was testing the finished article for the first time! So now I always work out how much sideplay I need for my arbitrary 4 foot minimum radius, and work out the maximum spacer requirement when including the width of the frame material. I don't take on trust any "P4" branding. "EM" branded spacers are often what I have used, as you have also mentioned. The wider the spacer the more convenient it can be for motors etc but the less the sideplay, as you have said. Another thing I gradually realised, centre wheels of a six coupled loco might not be quite halfway between the outer pairs. An eight coupled loco won't have any wheels exactly half way between the outer pair. In both cases there will not need to be so much sideplay as on an exactly symmetrical six coupled for a given wheelbase. A 4-4-0 or 0-4-4 will have a very long wheelbase if the bogie is fixed at a centre pivot.

Regarding the MJT units I use a permanent marker pen to stop the solder going where I don't want it to go, on the sliding bearing area, before soldering it all together. The marker pen used a few times is the best solder mask I am aware of just now, as it doesn't run, but survives the flux given reasonably quick soldering in the vicinity.

Re preparing the MJT bearing, there was some talk about broaches and reamers at viewtopic.php?f=19&t=4911&p=46149#p46149 I had a lot of really boring trouble boring out bearings till I got a reamer, I would say that was money well spent, I think less than £20. I realize you are talking about the cusp that may be just at the edges, using an oversize broach. But often I have found the whole bearing bore was just a tiny bit too small.

Regarding motor/gearbox combination, when I was starting I didn't have a store of motors, and it is quite an expense getting the wrong size. Choosing a motor and gearbox that fits is not so easy. The Branchlines and High Level people do acetate sheets or maybe one can print them at home, to lay out the gearbox and motor outlines on a drawing of the loco, to decide the best combination. I have used those firms, but not Markits and Comet. Maybe you are coming to all this.

So coupled with that I find it's all a lot easier all round to have a drawing of the loco, even just making a kit, unless it's really a High Level quality (if you see what I mean!), when all these decisions will have been thought out by the manufacturer.

You will be getting to this later, but the choice of motor and gearbox also depends on the top speed you will want.

I doubt you will mention my wacko assymetrical compensation, but when the frames are tacked together is the time to drill another hole a bit nearer the outer wheel for the compensation beam axle if going down my road to damnation.

This is great reading your thing here. I wish Markits spelt Assembly properley... :D

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Allan Goodwillie
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 8:35 pm

Thanks Julian,

Yes there are lots of things here which I will be going into and you have pointed out very well some of the more subtle points of designing for side play and some of the thinking that is required. Especially the relationships due to wheelbases and overall length of wheelbases might I say. On my Scott's road layout which I am going to build, on the real thing the Caley 0-6-0T was not comfortable on some of the curves in real life, even J83's that were tried out on the line as a possible locomotive type caused a few problems - the Large Barclays were perfect with their much shorter wheelbase. There was an 0-8-0T proposed but it was decided not to tempt fate. (Might just build it though!).

My advice to the starters group was to consider what their layout parameters were and build accordingly. As you know I try to add a fair bit of flexibility and do often use the EM gauge spacers. Those that are at the first loco chassis stage will probably do this to maximise their first engine's flexibility for a layout as yet unbuilt. My locos can pretty much operate on any S4 layout.

Phil's the first to come over tomorrow to get to the point of the chassis running. He is near it although there have been a couple of problems with the gearbox, which we will cover.

The reamer I have had for 40years and have found very useful.You are right about it being mainly the cusp - particularly on the gearboxes, but often on chassis more has to be taken out if fitting a bush for a fixed axle. The way it's faceted seems to ensure even amounts taken out and a regular hole cleared. I use mine all the time.

Your other comments are all relevant and you are right I will be covering everything thoroughly and will be looking at the asymmetrical beams - not such a crazy idea. I think I have mentioned top speeds already and what the locomotive is to do, but will be looking more closely at choices of gears pretty soon as well as info on the web that will help. I know we both like Chris Gibbons units, but I have had a rather odd thing happen to the gearbox on 80A and a similar problem with Phil's gearbox. 80A was one of the initial three engines I built for Burntisland so that it was ready for the competition. All Used Chris's gearboxes and the only other loco which was ready was John Wall's "Diver" which has the same type of gearbox. I will come to them shortly in the review as well as the Branchlines box which is also very useful. :thumb

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 8:52 pm

Continuing with the Comet Review -

Here are the written instructions very clear and superior to the previous brand. I went ahead and built the gearbox as according to instructions. One digression was to ignore the front bearing hole and to reduce the front plate to ease access. The motor has a 2mm shaft and tends to have less whip than one of a thinner diameter, so I felt fairly sure that whip would not be a problem - something not yet covered. I am not entirely clear as to why whip occurs - maybe someone more scientifically endowed can give me a good explanation as to why it can happen. My understanding is that a combination of forces when starting up can lead to the driveshaft going out of true momentarily giving a less than perfect get away as the shaft flexes.

Fitting a front bearing helps to hold the front of the shaft in such a way that whip is impossible. Some older motor types had one fitted as standard. Scew wound motors do not seem to suffer so much from this effect because of the very even take-off, I assume, so I have not found it necessary to add a bearing.


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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 9:07 pm

Looking at the parts they are similar, but the box is made in brass instead of steel. Otherwise the components fit together in similar ways as the previous example.


Opening out holes while the sheet is still flat using my reamer.


Here I am trying the small screws in the appropriate holes after using a broach to open them out.


Here I am opening out the holes in preparation for the bushes to be fitted. (one is already in place)


Here the bushes have been soldered in place - all still flat, the flanges of the bushes going on what will be the inside of the gearbox. (Note again where the etched lines are - they will again be the inside lines.)


Here is the gearbox folded and soldered waiting for the internal seams to be soldered.


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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 9:20 pm

Here. I have soldered the front plate on, bit rough looking but will clean up OK I still have to make the adjustment to the front plate which should have been done before fitting - much easier.


At this stage, as before, the squareness is checked.


A trial fit for the layshaft and gear.


By this time I had decided to cut away the top front bearing hole and did this using my hacksaw. I am also checking that the axle also fits and turns freely.


The motor and worm are fitted together and tried in place using the small screws provided with the motor. A 1616 round can in this case.


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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sat Aug 06, 2016 9:32 pm

Seen from the front the fixing screws are quite clear, but the other gears have not been fixed in place at this stage. The large hole in the rear part of the plate allows for movement of both motor and worm.


Here the layshaft and gear are being fitted in the correct off centre way as per instructions.


With all the gears aligned and a length of axle material fitted into the bottom 50:1 gear
the motor is tested under power to check that all is well. A little lubrication and light oiling at this stage is required. If all turns over OK then I give the gears a run. Half an hour at half speed each way then the same at top speed.


After running I clean out any debris using my Electroclean spray to eliminate any tiny particles created during the running in.


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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Sun Aug 07, 2016 8:35 pm

I would like to take a look at a couple of gearboxes now that allow for more flexibility. Smaller locomotives require perhaps different approaches. Most bigger engines allow you to fit a descent sized motor and most combinations of gears either centrally or on the back driver.

The first Gearbox I would like to talk about is similar to the previous two as it has a layshaft, slightly different in its layout, but it does allow for at least four possible positions for the final drive. It is known as the Branchlines Multibox. A very useful piece of kit

(1) under the motor
(2) directly down, similar to the drive position on the Comet box
(3) driving some distance forward from the motor, similar to the drive of the Markits box
(4) driving well forward allowing for a low position for the motor

This allows the gearbox to be used in a huge number of locomotives. It is robust and has lugs as well as end positions for motor fixing as can be seen through the packaging. At first sight there seem to be too many wheels, but this is how the gearbox is designed using an additional spur gear to make things more compact and for the gears to have a bit more strength. The machining, particularly,of the first drive gear and the worm are a thing of beauty. :)


Looking at the packaging there is a small diagram showing how it looks when made up and gives a critical dimension of a centimetre from the bottom edge of hole number 4 which is the hole directly below the motor, this is useful to gauge just how your motor might fit if you have a drawing of it. You are told it is suitable for 1/8th axles - this set has 80:1 reduction ratio gears and 2.0 worm bore.

Just by looking we can see that there is a steel (maybe nickel-silver) etch with two sides and a rear all in one etch with fold lines. There are three brass wheels with gears and grubscrews,one of which is a spur gear which operates alongside the first drive wheel which transmits the drive to the final drive on the axle a worm wheel with a grubscrew, a layshaft and 2 Phosphor/bronze bushes - all can be seen inside the packet. There is clearly a sheet with instructions, unreadable from the outside however, but it does say the gearbox is suitable for 00/EM/P4.

It all works due to the clever design of the side plates and a gear set which also allows for up to 80:1 gears which are strong enough to drive a heavy freight locomotive with a long train via the extra wheel on the layshaft. I will not go through all of the instructions which are completely comprehensive and straightforward for the beginner. :shock: By far the best written of all the notes we have looked at, with lots of useful comments and additional ideas. Like the other motors it is a little difficult to get to the lower of the two attaching screws - the easiest thing is to take out the layshaft in each case. :idea:


The photo above shows how the spur gear transmits the drive to the bottom gear and the axle. It is easy to fit.


This side view shows the gearbox made up rather conventionally with the excess side material taken away - this motor is for one of my Barclay tanks. It also shows the cutaways on the side sheets which help you to see to adjust the screw settings on the worm gear when setting up.


This is a top view showing quite a robust steel worm gear, It is s pity the hole in the back plate does not allow for the removal of the motor just by taking the attaching screws out (If they were in the side lugs). The alternative, if the attaching screws are fitted from inside the gearbox, is to take off the worm drive and that would allow for the second screw to be undone to release the motor. No big deal.

Overall a good piece of kit combining much of the best of the other gear sets we have looked at and giving greater flexibility as well. :thumb
Last edited by Allan Goodwillie on Fri Aug 12, 2016 9:28 pm, edited 1 time in total.

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Mon Aug 08, 2016 2:47 pm

The next flexible gearbox that is commonly used is the High Level Gearbox. This gearbox allows for a range of final drives by the use of a pivoted section of the gearbox.

I am not going to go into detail so much with this product as Chris has put a good deal of effort into his excellent website and I would prefer to guide you there just to see what the box is like and how it is put together. There are, in the gearbox section, downloadable drawings of all the boxes to allow you to try them out against your chosen prototype drawing as well as a section giving some advice as to how to choose a gearbox/motor combination given a particular type of locomotive and its intended employment. A section on available motors and their sizes, drive shaft diameter and speed range. There is even a final speed calculator to determine locomotive top speeds in scale.

file.jpg (78.4 KiB) Viewed 5932 times

The packaging is something which Chris could improve on as can be seen above, but it does tell you that this is a set of 80:1 gears and that the motor shaft should be 2mm, but beyond that nothing.

Here one opened and revealing the contents-


However Chris has made sure that the construction notes that come with the gearboxes are comprehensive. Like the other gearboxes we have looked, at I can recommend them and highly recommend the website and Chris himself as he is always able to give help and will also tell you when not to buy if he feels that he does not have a gearbox that is suitable - it can happen as in the case of my WD which was going to pull heavy loads up gradients and Chris suggested that maybe in this case there were better alternatives on the market. I admire his honesty and needless to say I have gone back for other equipment since. I must say at this point that Andy Mullins and the "new owners"of Branchlines, Brian and Isabel Osborne are all very good at customer relations and for handling things on the phone.

So this is the site for High Level-

The gearbox has N/S etches for the main and secondary frames. It has cut away areas for seeing how the worm and the upper gear are to be meshed. The worm is brass as are some of the gears, although the layshaft gears are of a fairly tough plastic.
The layshaft transfers the traction to a spur gear which is allowed to revolve around another shaft which also acts as the pivot to allow flexibility of the final driving axle. The bottom part of the gearbox can be reversed to allow for final position below or in front of the gearbox. It gives just the same arc of flexible drive as the Branchlines box, but allows for any position in between.

The strengths of the gearbox are its flexibility and range - I cannot cover the range here, but they allow even up to a 108:1 ratio for very small prototypes requiring ultra slow running, as well as having something that is bound to fit. The downloadable sheet is again very useful showing the configurations of gearboxes.

The packaging contains all the parts, sometimes at shows Chris will even make up a set of parts there on the spot, if he has run out of ready made sets. On Burntisland the engine builders have mainly used High Level boxes as they particularly suit small Victorian locomotives. The first three locos I built for Burntisland at the first Scalefourum to get us up and running all had Chris's High Level gearboxes as well as the "Diver" built by John Wall. All have given very good service from the off. Only recently has no.60A given trouble and I will go into that later as Phil's loco which he is building suffered the same fault from the off - something surprising, but easily cured.

Phil has been over yesterday to move things on with his loco's High Level Gearbox yesterday and here is his gearbox ready to be installed - more on this later.


Finally a shot of 60A after about 15 years of occasional wear - the old girl could be doing with a repaint - might just get the paint scheme correct this time!

No.80A back in working order
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Last edited by Allan Goodwillie on Fri Aug 12, 2016 9:29 pm, edited 1 time in total.

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 09, 2016 1:29 pm

The last type of arrangement I wanted to cover briefly, just in case one or two are planning on using them, is the ready made. I will not go into any depth except that someone without any experience of building locos may think it is not a bad way to get your first loco up and running, if you do not want to tackle a gearbox then simply buy one ready made. ;)

When I had finished the first season at the Melrose model railway museum, virtually all the gearboxes had worn out :o and I was short of time to replace them. :shock: I bit the bullet and bought a whole load of Portescaps and replaced the previous mechanisms over two or three evenings. Most of the early locomotives are still running with these 30 years later. :) I have started to replace some of them, but only because I am building completely new mechanisms. Will I buy new Portescaps to replace? No, as the Maschima motor gives just as good an output of even power and given some of the modern gearboxes a sometimes quieter running loco, although only my J38 is noisy. They are also quite expensive to buy and that is a consideration as well. Others have complained in recent years that Portescaps of later batches tend to be noisy, as I said apart from one, I have not found that to be the case.

This is as much as you can see from the outside of the packaging.

This is one motor a 1219 recently taken from a loco that is undergoing a fresh chassis, but as you can see the motor/gearbox comes as one unit, in fact they warn against interfering with the fitting (although the Scalefour stores sell alternative gearbox sides (MJT) to allow for different final drives.

So if you are intending using a Portescap, that you have had for some time, then go ahead and use it you will get good running and a long lasting mechanism. You have to fit some diodes into the circuit to give some protection to the motor - all that is explained in the notes you get with the motor. That is the only thing required for what is an easy fitment. Since we are building complete layouts, I should mention that Portescaps do not particularly like feedback controllers and are also less than keen on digital control - so consider that before fitting. :idea: A nice smoothed power source is what they love and will give superb running.

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 09, 2016 2:17 pm

Finally :D some of you may have bought Exactoscale boxes as it is also possible to buy them ready made. This may seem like a quick option, but it also means buying into their wheels and other pieces of equipment. If some of you have bought items in this range, maybe a few comments might be advisable. The gearboxes and the gears themselves are very very fine, beautifully engineered and similar to the original Studiolith from way back.

Now, my first few locomotives were all fitted with these and I was new to what was to become P4 (although I already had built about a dozen 00 locomotives by that time so had a little experience already of such things.) My first P4 locos ran with Studiolith as well as Romford gears/gearboxes and had KTM motors or Romford Bulldog motors, which for their day were considered good motors although wound conventionally. Pendon used KTM.

I was so pleased at the step change in running achieved with the Studiolith gearboxes, and if my layout had been small scale, short loads only, run occasionally at home and shows, that would probably have been fine. However 7 hours per day, 7 days a week running at Melrose over the first season saw the death of all these gearboxes. Now there is nothing wrong with the gearboxes as such as I said running is superb, but they have their limitations on heavy engines, big trains, lots of running. They were never designed for such. They have advantages in the gear ratios for specialised use, for example a small loco where you want to see below the boiler, you can use an 18:1 in the loco driven through a 2:1 box in the tender.

I have experimentally built a WD with a 40:1 in the loco and a 2:1 in the tender using tender drive and driveshaft going through to the locomotive. The idea being a slow trundling WD on a long coal train. Despite the fineness of the boxes the slow movement is spoiled by the noise coming from the gears and motor, despite filling the tender with lots of soundproofing. :cry:

All the gearboxes are available to assemble as well, but you do have to be careful as they can be easy to strip. Exactoscale also provide an excellent selection of flexible drives that are very useful. Despite my own experience an Exactoscle gearbox is perhaps not the best to start with. Exactoscale products are excellent generally and each designed to get around a problem - so very interesting solutions, but they do require care and a modicum of experience, so for starters, perhaps no. However if that is what you have have a crack at it. I am not going to look at other motors as such just now, perhaps later, as various motors turn up.

Here we have an 18:1 gear which can be combined with a 2:1 to give a 36:1 overall ratio

Lifting up the flaps you can see the parts - rather a lot for a small box and some notes.

Samples of the 2;1 (the long one) and 36:1 made and part made to give some sense of the diminutive size of these boxes which can be hidden in almost any small loco

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Allan Goodwillie
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 09, 2016 2:24 pm

Well that covers what should be done, or can be done before assembly of the chassis. The method we will be using is the same as can be found in the West of Scotland "Build a chassis" thread in the Beginners section where you will find the method and tools, jigs, etc. required.

Part one-

Allan :D

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Re: Livingston - West Lothian Starters Group

Postby JinglingGeordie » Tue Aug 09, 2016 9:32 pm

Allan, I have read all that you have added to the forum. I have absorbed about a quarter of it!! I will be re-reading it carefully again. You made a comment about it maybe being too basic. NO, IT IS NOT. It is just perfect for people such as me who have never done anything like this and have always looked in awe at those who could. I can now see that nothing is impossible if you go about it the right way. I have a Judith Edge kit for one of the wee 0-4-0s which cuddled up beside the Y9s round the turntable at St Margarets. When I have looked at it I just go into panic mode!
I have learned one thing - I had made a cutting board with the V cut out but did not think of a wee block screwed to the underside to hold it in the vice. That will be done tomorrow.
A broach - from the photograph it looks like a square tool in a round hole again. Is that correct? What is the difference between a broach and a reamer? I don't have either. Is another investment in Squires called for here?

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 09, 2016 10:33 pm

Hi David,

The tools are different, broaches are 5 sided and are worked between the fingers to open out small holes - most of the little ones we use are used for jewellery making or watchmaking. For years I did without them, using instead A ROUND NEEDLE FILE! However after borrowing a set one time I realised they were much quicker at opening out holes. There are a number of techniques with them which I will not go into just now, but I don't know why it took me so long. I think the bigger one is still a broach it too has 5 sides. I use this for working on bushes etc. Again I used to use a round needle file, but again it is a superior tool. I am not expecting for everyone to go rushing out and buy tools, but you might consider these. When you come over I will show you how to make the most of them. They are particularly good for opening out holes in coupling rods and valve gear, handrail knobs, etc.

A reamer tends to be used for larger holes and is not just faceted, but has curved sections between the facets allowing for a greater dig as it were :thumb . Depending on the size it may have many more facets than the broaches. I am sure that James may come back with more information and probably have a better definition. Sorry no photographs tonight it is a bit late - I will see you on Saturday and could bring along the tools for you to have a look at and maybe try out. :)

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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Fri Aug 12, 2016 9:39 pm

further on reamers, talking with Jim, who had an engineering background before entering the ministry, he agreed with my description of the article and the general functioning of a reamer, but took it further to say that there are different types as they can be made to different tapers to produce tapered holes. They also come with a sort of keyed end to allow them to be used in power drills with the key fitting between the mandrels in the chuck. This gives better grip and stops them turning unlike drills where sometimes this can happen. :(

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Re: Livingston - West Lothian Starters Group

Postby billbedford » Tue Aug 16, 2016 7:40 am

Isn't the square end on hand reamers there so that they can be use in tap wrenches?
Bill Bedford
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 16, 2016 1:59 pm

Hi Bill,
Yes you are right , if they have a square end this is so, but larger ones also have additional spines and are meant to be used in power equipment to stop the reamer turning in the mandrel.

Allan :)

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Re: Livingston - West Lothian Starters Group

Postby Terry Bendall » Wed Aug 17, 2016 6:35 am

There are hand reamers and machine reamers but these are normally made in the larger sizes - too large for what we need, and are made with a taper shank to fit in the tailstock of a lathe. It is of course possible to hold a hand reamer in the drill chuck of the tailstock. A reamer will normally follow the drilled hole but in thin material may get off course is used by hand.

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Re: Livingston - West Lothian Starters Group

Postby njggb » Thu Aug 18, 2016 10:14 am


Below is a hand reamer and it has a square section at the non-business end for a tap wrench as described above by Bill.

single reamer.jpg
This is a 3/16" hand reamer, the square section is on the right hand side.
single reamer.jpg (231.21 KiB) Viewed 5492 times

Two types of tap wrench are illustrated below. The convention is to rotate the reamer in a clockwise direction as you would a tap. Note that the reamers have flukes, the cutting edges, that have a small twist to the left as you look from the square end. This is to deter the reamer form "screwing" into the hole and taking charge of the operation. This gives the user greater control.

The same reamer with two different types of tap wrench/
tapwrenches.jpg (207.98 KiB) Viewed 5492 times

Hand reamers have a lead in in that the first section, up to a third of the length, will be under size and the final two thirds will be at full size. Machine reamers have less of a lead in as it is assumed they will be used in machines with a degree of automation and a higher degree of control.

Machine reamers usually have a morse taper non business end. The one illustrated below is a 1/2" machine reamer with a number 1 morse taper, it would probably have to have a sleeve fitted to bring it up to the number three morse taper of a lathe tailstock. The other one is a machine reamer with a more hefty square end.

Both of these is a machine reamer.
machineReamers.jpg (221.81 KiB) Viewed 5492 times

Other types of reamer, the same name but a slightly different function, are taper reamers. They are used to open up holes but will cut a tapered hole. They can be used with thin sheet with greater success than hand reamers as Terry has stated. Some taper reamers are used to produce a specifically tapered hole for taper pins. taper pins can lock gears to shafts as an example, a gentle tap will lock the joint solid. A tap in the other direction will free the taper pin to allow for easy disassembly.

tapered reamer.jpg
A tapered reamer usually comes with its own handle. This example is generally used to enlarge holes.
tapered reamer.jpg (216.69 KiB) Viewed 5492 times


There are two sorts of broaches, cutting and smoothing.

Cutting broaches as stated above by Allan usually have 5 sides, the more the number of sides the more "circular" the finished hole will be. The "flats" on these broaches are hollow ground on larger examples. This means that there is cutting "clearance" allowing them to cut more efficiently. They can be sharpened with a fine stone a few times before the hollow ground is eliminated.

These are small broaches ranging from 0.7mm up to 2.5mm. They are sold in sets normally. You can see the "faces",
smallBroaches.jpg (183.52 KiB) Viewed 5492 times

Smoothing broaches do what it says on the tin. There are lots of very small cutting edges.

The sequence of operation would be to cut and then smooth. I have to admit I do not have any smoothing broaches. I start to size the top hat bearings with a twist drill, specially set aside for this purpose, and finish with a hand reamer.


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Will L
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Re: Livingston - West Lothian Starters Group

Postby Will L » Thu Aug 18, 2016 1:32 pm

njggb wrote:Smoothing broaches do what it says on the tin. There are lots of very small cutting edges.

The sequence of operation would be to cut and then smooth. I have to admit I do not have any smoothing broaches.

I do have a set of smoothing broaches, and I think you would have a very particular need for a smoothly finished hole before you'd bother to get them out, although there existence presumably proves that somebody does.

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Re: Livingston - West Lothian Starters Group

Postby njggb » Thu Aug 18, 2016 4:44 pm

Yes, Thanks for that, I have subsequently been told that they get stuck fast. Apparently you should apply a small amount of oil to the hole before inserting the smoothing broach, then proceed with great care not to force things.

I don't have any, so it is not a problem that I will encounter.


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Re: Livingston - West Lothian Starters Group

Postby dal-t » Thu Aug 18, 2016 5:06 pm

Excellent piece of clarification, James, many thanks on behalf of all non-engineers like myself who struggle to acquire this sort of knowledge. However, I had to take issue with one assertion -

njggb wrote:taper pins can lock gears to shafts as an example, a gentle tap will lock the joint solid. A tap in the other direction will free the taper pin to allow for easy disassembly.

That may be the theory, but in practice, all the times I've taken car components apart, the 'tap' for easy disassembly has actually been an increasingly frustrated series of hefty whacks, application of heat from the welding torch, repeated doses of 'releasing' fluid, levering with any length of rod or bar to hand, and a steady stream of increasingly profane incantations, before a sudden parting. Thank goodness none of that is necessary in our (small) scale endeavours ...
David L-T

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Allan Goodwillie
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Fri Aug 19, 2016 8:06 am

Thanks everybody for recent replies and going to the trouble of looking out pieces of equipment and photographing them, it all takes time to write up and is much appreciated by all of us. :D

I may be wrong, but I think that the smoothing broaches are particularly useful for watch and clock making where you may need fairly frictionless pivots for example, not something we require very often. - just a comment I am not expecting any confirmation - more important that people are building models!


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Re: Livingston - West Lothian Starters Group

Postby njggb » Mon Aug 22, 2016 11:30 am

Hawthorn Leslie 0-4-0

Well I now have a completed and running chassis.

Completed Hawthorn Leslie 0-4-0 chasssis.
HarthornLeslieChassis.jpg (202.84 KiB) Viewed 5314 times

Now I have to do one more thing, ensure that the pivot for the compensated axle is in the right position vertically. If I attach some M3 hex spacers with M3 screws to the two chassis holes I can rest a rule on the top of those and on that a spirit bubble.

The observant among you will notice that the photo above is at a later stage than the following pictures of the chassis. I forgot to photograph the chassis alone, sorry.

The chassis with one M3 hex spacer screwed on.
oneSpacer.jpg (188.95 KiB) Viewed 5314 times

Two hex spacers.
twoSpacers.jpg (176.22 KiB) Viewed 5314 times

However as a result of a conversation with Allan Goodwillie at a recent club meeting I thought that I could make a universal "loading cradle" to add lead when running in. All I wanted was a plate with a slot down the centre to take the M3 screws that could be tightened in any position for any chassis. Where had I seen a plate with a long M3 clear slot? Enter my second connecting rod jig. Remember that I had to make a second as the photos of the first were badly focused. All I needed to do was to file the edges of the angle to widen the slot to a clear M3 dimension and reassemble it. Hey presto.

The small spirit bubble placed in the modified connecting rod jig.
bubble.jpg (183.16 KiB) Viewed 5314 times

Here I had adjusted the pivot for the compensation in a vertical pane, The chassis will be parallel to the track. Please note that the bubble is not centred, but that is because my bench is not level and this offset reflects that situation.

A note about filling aluminium; rub chalk into the teeth of the file and that will stop the swarf/filings accumulating in the file teeth. To clean the file finally just use a file card as normal.

Now when it comes to running in, lead can be safely added to the channel formed by the two angle sections, thus;

Lead placed in the channel section.
leadLoad.jpg (206.29 KiB) Viewed 5314 times

The channel provides for a secure location for all sorts of load, as below, a bit over the top but hey ho.

An automatic centre punch added as a running in load.
anyLoad.jpg (189.02 KiB) Viewed 5314 times

So I managed to kill two birds with one stone.


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Allan Goodwillie
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Re: Livingston - West Lothian Starters Group

Postby Allan Goodwillie » Tue Aug 23, 2016 3:21 pm

Thanks James for putting the example of the jig adaptor you made up on this thread. Looks good! I hope the others may consider making an adaptor for the Jig as you have done once they see its usefulness.

I left off posting my version, until you posted your design as I think yours is very pucka and has a superior look to mine and better engineered. I had thought about using similar posts, but was thinking that it would mean the starters having to deal with more equipment and taps etc., so my adaption is a little simpler to make. I like the use of the level by the way. I will have to find out where to get some myself for fitting into my baseboards.

Congratulations in getting your chassis running :D :thumb - you are the first to get it up on the web here, I am sure it will encourage the others to start postings. Phil, I know, is almost at the same stage.

Meanwhile here is my version of the adapted jig-


I have used some of the brass strip I gave out to everyone for making their construction jig, but any metal strip will do. Drilled a couple of holes and bent a couple of right angles and finally added some nuts and bolts. The design does allow for things getting in the way, ( like the drive shaft of the motor.) as there are different ways to set the angled strip. I should maybe have exaggerated this shape even more as the loco could maybe have had a flywheel. This would have meant it showing in the cab - something I would avoid and that is probably why I had not thought about it myself when making my version. It took about half an hour to make.

I had a further thought about all this and decided that it could also be used turned upside down for running in motors and chassis - something which I always do when tackling the bodies. The loco is one of Chris's smaller Barclays which I started on Friday. It is just about complete - I am gardening tomorrow, so it will have to be the end of the week before the engine is ready for painting. Painting will have to wait until I get my set of larger Barclays finished.


Was out on a photo shoot with the West Group on Sunday last week so could only be at the East Group on the Saturday - both excellent days! The last photo is of a Giesel version "in the nude" :o :shock: :twisted: :D as it were, taken at Dunaskin. This happened to be the loco I was building and I did not have a rear view, so was not sure whether the number was definitely on the back buffer beam.


No 8 was one of the Barclays which worked at Methil and occasionally East Wemyss so hopefully it is destined for use on Scotts Road when I get it built. I am sure it will probably appear from time to time along with Julian's version of the same thing on our Calderside extension when we get it finished as well.

Here are two more photos of the loco when working at Methil and clothed in NCB grime. I will maybe use this loco as a "master class" in painting and weathering when we get to that stage with the engines in a couple of months. It is thanks to Charlie that I have the photographs and the kit to have a go at. I hope he approves when I finally get it completed.



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