Has anyone used the society's wheel form tool yet?

hollybeau
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Has anyone used the society's wheel form tool yet?

Postby hollybeau » Fri Jan 20, 2023 6:58 pm

After months of prevarication on my part I have today finally plucked up the courage and ordered one of the Society's form tools. I am not a stranger to lathe work but I have never used a form tool and wondered if there was anyone out there who has bought one and used it yet to reprofile wheels to S4 standards.
The background to this is that I am currently building a Midland 483 Class loco (the forerunner to the LMS 2P) from a modified Eames/Jamieson kit and sitting on a Comet/Wizard 2P chassis. The Midland loco differed principally from its later reincarnation by having 7 ft drivers. As it happens I found wheels of the correct diameter in my bits box. I suspect they are Sharman's but they may be early Gibsons. Try as I may by chamfering and polishing the ends of the axles and having a slight countersink on the backs of the wheels they run with an unacceptable amount of wobble. This is of course a particular problem given the large diameter of these drivers. I could buy some more Gibsons (they have improved in this regard over the years I find) or I could get some Ultrascales which I find assemble wobble-free. Alas, they are not available in this size. It then occurred to me that the exact wheel (in terms of diameter) is available from Markits and this could be mated with what is described as a "Romford P4 axle" from 247 developments.
I have a small Sieg lathe which I hope will have enough "grunt" to do the reprofiling (running slow with some oil). I should add that I propose to buy EM wheels so as to reduce the amount of metal to reduce. I also plan to use a collet rather than the (questionable accuracy) of my three-jaw chuck.
My first thought was how to hold the wheel. Clearly simply putting the wheel on a Romford axle is not going to work with all that torque going through the squared off end. My solution at this stage is to pass the axle (tight fit, or use a sacrificial axle soldered in place) through a brass "boss" , faced off on the lathe and then with the wheel bolted onto the face with some BA bolts and washers into tapped holes in the boss. This should retain the wheel as well as holding it perpendicular to the axle.
Any thoughts anyone?

davebradwell
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Re: Has anyone used the society's wheel form tool yet?

Postby davebradwell » Fri Jan 20, 2023 8:22 pm

Before launching into a heavy engineering job, if the existing wheels are Gibson, I suggest you try pushing the tyre off the plastic centre and truing this up. Turn a slightly tapered mandrel a few thou' under 1/8" and just push wheel centre on lightly. You should be able to persuade it to run without wobble and will probably find the eccentricity is down to a mould pip or similar. Perhaps you may have to take a light skim to true it up. In extreme cases if a heavier skim is required then 5 thou' styrene can be stuck round the rim and skimmed ot re-size.

If they're Sharman then it would be easier to drill out and bush them but you'd have to find something that would stick to nylon.

DaveB

Terry Bendall
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Re: Has anyone used the society's wheel form tool yet?

Postby Terry Bendall » Sat Jan 21, 2023 10:17 am

hollybeau wrote:I have a small Sieg lathe which I hope will have enough "grunt" to do the reprofiling


I don't know theSieg lathe and it might depend on which one you have. Having looked on line it looks like it should be capable of the job.

hollybeau wrote:My first thought was how to hold the wheel.


I would advise that you look at Jeremy Suter's thread on here a while back at viewtopic.php?f=132&t=6350&start=75
"Making an Arbour to re-turn Heljan shunter wheels to P4 standard" Jeremy's method is different from what I have used in tbe past but it is very good. It is also looks similar to the method you propose.

hollybeau"]I also plan to use a collet rather than the (questionable accuracy) of my three-jaw chuck.[/quote]

A collet is always going to be more "true" - ie without wobble than a three jaw chuck, unless the chuck is new. A four jaw chuck will allow a larger bar to make the mandrel to be used but them you need to be able to set the bar running true using a dial test indicator. (DTI) Depands on the largest size of collet that you have

My methods of making a mandrel and information about turning wheels were including in the series on using machine tools that appeared in Scalefour News between 2008 and 2010. Also uincluded is using a four jaw chuck and a DTI. If you done have the paper copies they are available in the members' area in the News archive. You may find a few things that are useful. I used my method of making a mandrel when testing the form tools before they were made in quantity.

Terry Bendall

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Hardwicke
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Re: Has anyone used the society's wheel form tool yet?

Postby Hardwicke » Sat Jan 21, 2023 2:42 pm

I'm saving up to buy a tool post
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

Jeremy Suter
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Re: Has anyone used the society's wheel form tool yet?

Postby Jeremy Suter » Sat Jan 21, 2023 7:11 pm

Hi Brian

I sent you the tool this morning.

Terry did point you in the direction of my turning thread which deals with re-profiling wheels.

If you use Markits wheels the problem will be holding the the wheel central.
An arbour to fit could be made easily.
You could use the square axle and an 1/8th collet but you will need to put a pin though the spokes or crankpin hole, to stop it from twisting on the square base when force is applied to the tyre. I would also suggest using an extended axle and put the wheel on the axle the wrong way round. You will have to make sure that you have the wheel spinning without wobble so fitting between two clamping blocks or mount the wheel to one block with 3 screws through the spokes to alter the pitch if needed this will also stop the wheel twisting on the axle.
A little bit like this one.
IMG_7740[1].JPG

The next problem will be the thickness of the wheel, Markits wheels are on the thick side. Not wanting to alter the back to back as it is fixed axle length / back to back. I don't know if the Markits p4 axles are set to there wheels when they are turned to the correct profile or not.
You could be making your own axles to suit the wheels that you have re-turned which would be another job entirely.
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Sat Jan 21, 2023 7:17 pm

Thanks for your responses.

Dave: It may be my inadvertent use of the wrong term but what I mean by "wobble" is when the wheel goes "in and out" when seen from above - as opposed to your use which is about eccentricity of running around the axle. Your solution therefore won't work here.

Terry: I am familiar with your articles. They were very helpful when I started to use the lathe some ten years ago. I do occasionally go back and re-read them. I'll have a look at Jeremy's article.

Bryan

hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Sat Jan 21, 2023 7:34 pm

Thanks Jeremy (and for so quickly sending the form tool).
Our posts have "crossed": I wasn't aware of yours when I last posted.
Your photo shows exactly what I had in mind. I have never used Romford extended axles so don't quite follow what you mean by using the axle the wrong way round. Doesn't that mean that the short end of the axle is on the driven side? I was planning to have as long an axle as possible being held in an 1/8" collet.
I have yet to order the P4 axles so will wait to see what back to back they achieve and try and adjust accordingly. Making my own accurate S4 axles with squared ends aligned with each other and with a thread cut in them is way beyond my abilities. If the P4 axles from 247 developments turn out to be unsuitable I will try and use a sleeve or muff to join two half axles (but how I do that on the gear wheel is anyone's guess). For now I have some old Romfords in the stock box and will use then as guinea pigs to see how the actual turning goes.

Bryan

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Re: Has anyone used the society's wheel form tool yet?

Postby Jeremy Suter » Sat Jan 21, 2023 8:01 pm

Hi Bryan
This is what I mean by a Markits extended axle the threaded screw part is much longer.
IMG_7742[1].JPG
The wheel is on the axle the wrong way round and I have not tightened up the nut to show the back, although the square end of the axle is not visible it is in there. The wheel does not suit the arbour holes so I have only put two screws in it.
IMG_7741[1].JPG
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Sun Jan 22, 2023 7:50 pm

Having been inspired by Jeremy I have made a start. I faced off some 20mm diameter brass bar, centre drilled it 3mm, removed an area around the hub to allow for the protrusion on the back of the Romford wheels and then parted it off at about 6mm deep. This was to allow enough metal to support the wheel and allow the bolts to have purchase but leaving enough length in the 00 axle to allow it to be gripped by the collet. I then reamed out from the back until the axle was a tight fit in the hole. The wheel was mounted on the front and nutted up and then two holes drilled (1.4mm) and tapped for 10BA bolts (The other hole you can see was a first go using 2mm metric bolts which proved to be too large to go between the spokes.
This is the state of play at this stage:
20230122_143134.jpg

This was then mounted in the collet and placed in the lathe:
20230122_150427.jpg

20230122_150442.jpg

Having regard to Jeremy's advice not to use the form tool to do all the reprofiling work (and I don't have it yet!) I turned down the flange depth to around 0.5mm . I also reduced the width of the wheel from 2.7mm to 2.35mm. I don't want to touch the back of the wheel/flange at this stage not knowing the back to back of the 247 development "P4 axle" . These are only old wheels from my 00 days over 40 years ago so they don't owe me anything. This is a trial run ahead of buying the new 7ft drivers. I plan to buy an extended axle and try that too. Final photo is of where I have got to.
20230122_151616.jpg
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Winander
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Re: Has anyone used the society's wheel form tool yet?

Postby Winander » Sun Jan 22, 2023 9:04 pm

Jeremy Suter wrote:I would also suggest using an extended axle and put the wheel on the axle the wrong way round.

hollybeau wrote:so don't quite follow what you mean by using the axle the wrong way round

I see you have put the wheel on the right way round because you wanted to face the front. I do, however, think you misread what Jeremy said, and in my experience that man always has a reason for the methods he uses. I suspect it's to give you more wiggle room with the form tool.
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Terry Bendall
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Re: Has anyone used the society's wheel form tool yet?

Postby Terry Bendall » Mon Jan 23, 2023 8:23 am

Winander wrote:in my experience that man always has a reason for the methods he uses. I suspect it's to give you more wiggle room with the form tool.


The form tool wil work with the wheel mounted either way round, and since both ends of the tool have the profile made in them, but opposite ways round on each end, it allows for this. I have always fitted the wheel to the mandrel in the same way as Bryan has done.

hollybeau wrote:These are only old wheels from my 00 days over 40 years ago so they don't owe me anything.


This is a very good way of gaining experience of using the tool.

Terry Bendall

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Re: Has anyone used the society's wheel form tool yet?

Postby Crepello » Mon Jan 23, 2023 11:23 am

I wonder how practicable it would be to shift the tyre forward on the centre casting, so that the finished
back-of-flange to front-of-boss dimension comes out to scale?
It would be quite a desirable outcome for many outside cylinder locos where clearances are restricted.

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Re: Has anyone used the society's wheel form tool yet?

Postby Jeremy Suter » Mon Jan 23, 2023 6:03 pm

Well done Bryan that looks very nice little set up.

You don't say how the brass base is mounted to the axle.

Is it a force fit, or secured with a grub screw. Reason being. If its not fixed firmly then it has the possibility of spinning on the axle centre.
The square hole in the centre of the wheel is the only thing stopping the wheel slipping on the axle, when force is applied to the rim.
The Markits centres are softer than the rim so the centre will tear rather than the rim will be cut if you try to take slightly too much off at a time.
As the square end of the axle doesn't go all the way through the square hole in the wheel putting it on the axle back to front will save the quartering on the inside.

Crepello wrote:I wonder how practicable it would be to shift the tyre forward on the centre casting, so that the finished
back-of-flange to front-of-boss dimension comes out to scale?
It would be quite a desirable outcome for many outside cylinder locos where clearances are restricted.


Moving the tyre forward on Markits wheels, I wouldn't like to try they are very firmly fitted together I assume the insert is moulded into the tyre. Even the insulated wheels are well stuck
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Mon Jan 23, 2023 7:45 pm

I have now received the form tool (excellent service as always from Jeremy) and have "cut" my first reprofiled wheel.
I had removed as much of the flange as I dare with an ordinary cutter and reduced the width of the wheel (from the front) to 2.35mm (I reckon I could go further and reduce this to the recommended 2mm maximum but as there are no outside cylinders with this model I wanted to play safe). I had to pack the form tool up by some margin to get the cutter on the centre line (my lathe uses 9mm square stock usually) and I lined the tool up (by eye, by sighting through to the carriage below) to ensure the tool met the wheel at right angles. Using two magnifying glasses (!) I advanced the tool and made sure that the projecting cutter was just kissing the back of the wheel. I then made the cut, turning slowly and with very slow increments. It cut quite easily and quickly at first but when it was cutting across all its width it was possible to detect a different cutting tone. I am very pleased with the outcome:
20230123_143539 (2).jpg

The tyre is nickel silver on these Romfords and it cut beautifully and clean: I did not use any oil. Not sure how cutting steel tyres would perform.

Jeremy- the axle is a tight force fit. I had thought to solder it in solid at the back (and left a countersink in there for that purpose) but then realised I would not be able to do the small adjustments necessary to get the 10BA bolts to line up through the spokes. Your point about using a grub screw is well made and I will modify the brass "holder" (not sure what to call this- I don't think it is a mandrel) tomorrow before reprofiling any more wheels.
I now understand your point about mounting the wheel the wrong way round. I have ordered an extended axle from 247 developments for that very purpose and some of their "P4axles"
While on that subject, Brian Mosby, the owner of 247 Developments (and despite being located in South Wales is a fellow Yorkshireman and therefore a good chap- usual disclaimer) was telling me that these axles were originally made for Markits. They found they couldn't sell them (either at all or in insufficient quantities) and Brian bought the lot - about 300 axles. Since then he has sold out and has bought in a second lot. I find it odd that we have not heard more about these - there must be many locos running around out there on reprofiled Romfords/Markits that I am unaware of or modellers are buying them up for their stock boxes against the day when they figure out what to do with them.
Finally - comment to Crepello. I for one would not like to try and "move" the tyre on the wheel. Not sure how it would be done while keeping the tyre concentric and parallel to the centre or what effect it would have on the thin layer of insulation (which from the minute shavings taken off when reducing the front looks like the red material used to make Peco fibre washers).

Bryan
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Sat Jan 28, 2023 5:15 pm

The "P4 Axles" have now arrived from 247 Developments and I have assembled the wheels:
20230128_143642 (2).jpg

This photo is misleading in that the back to back achieved is 17.5mm i.e some 0.17mm under standard (the nut is loose in the photo to allow the wheels to be "staged" in this way). This is not a deal breaker. Remember these are only some old wheels used as a trial. When I come to do the correct 7ft (28mm drivers) I intend to begin to cut the profile as before i.e. with the "projecting tongue" of the form tool hard up to the back of the wheel then withdraw it and move it 0.085mm "outbound" . In other words the cut will shave a little off the back of the wheel when doing the reprofiling. There is plenty of meat in the Romford flange to allow for this. Failing that I could set the wheels up the wrong way round a la Jeremy and shave 0.085mm off the back before using the form tool.
If I were to use these wheels on another loco (and I have a Midland 990 Class in the to do pile which will suit them nicely) then my thought is to pack them out with a thin "washer". Interestingly Markits/247 Developments produce some 6 thou washers which they sell to convert ordinary 00 axles to finescale standards. (Item G71) and one of these would bring the back to back dimension to just about spot on.
All this having been said I have also put the wheels in the 483/2P chassis and given it a roll through my points and it performs beautifully! No wobble or roll!
20230128_143236 (2).jpg
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Mon Feb 06, 2023 8:04 pm

An update. The correct 7ft drivers have arrived from Markits. I ordered the EM profile and the wheels are clearly much closer to dimension and profile than the old wheels I practiced on. As such I could use the form tool straight away without needing to remove most of the overly deep 00 flange on the guinea pig wheels.
I was worried however about Jeremy's advice about making sure the axle/mandrel/wheel were all held tightly together to avoid the wheel spinning under load (and thereby ruining the quartering in the mazak casting at the back). I did try fitting them the other way round but in truth did not get on with it as I found it difficult to pack out the wheel to make sure it ran true. Instead, I made a new mandrel:
20230206_150504 (2).jpg

As I hope you can see this one follows the same principles as the mark 1 but the collet (the largest in my ER11 set) grips a brass spigot turned out of the solid. This was done on the three jaw chuck, parted off, reverse mounted in the collet and then faced up. I then drilled and tapped the face to take three 10BA bolts - thus allowing for slight alterations to enable the wheel to run true as well as holding the wheel secure. I also put in grub screws to hold the axle as per Jeremy's advice although I don't suppose they are strictly necessary anymore since the axle is only there to centre the wheel on the lathe: all the torque forces being done through the brass mandrel.
I have now turned all four wheels. That part of the job was quite easy. I have assembled the wheels on the chassis and it runs smoothly through my pointwork.
All in all I am very happy with this little experiment, one that I may do again on future locos.
PS The enlargement of the photo is a bit cruel!
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Re: Has anyone used the society's wheel form tool yet?

Postby Terry Bendall » Wed Feb 08, 2023 9:25 am

hollybeau wrote: I also put in grub screws to hold the axle as per Jeremy's advice although I don't suppose they are strictly necessary anymore since the axle is only there to centre the wheel on the lathe: all the torque forces being done through the brass mandrel.


Perhaps not needed but every little helps. :)

hollybeau wrote:The enlargement of the photo is a bit cruel!


It looks like the finish from the tool is not very smooth but the important thing is that it works which is all that is needed. :)

Terry Bendall

hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Thu Feb 09, 2023 7:51 pm

I have just realised that I omitted to mention one very important fact: when these wheels were assembled onto the "P4 axles" the back to back dimension was spot on to the society's standards i.e. no need to pack it out or take anything off the back face. I set the form tool up to have the projecting "lug" to just graze the back of the wheel. The flanges line up nicely. These wheels, which I believe are to RP25 profile, measured 2.5mm in width. I reduced this from the front to 2.25mm. I am sure I could have gone further but as this loco does not have outside valve gear/cylinders and there was enough clearance inside the Jamieson splashers I saw no reason to go further.
I hope this is helpful to others thinking of having a go.

Bryan

Jeremy Suter
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Re: Has anyone used the society's wheel form tool yet?

Postby Jeremy Suter » Sat Feb 11, 2023 8:06 pm

Hi Bryan
Well done with the exercise. I like the idea that the axle sits in the body of the arbour. I think that might be preferable to just fitting the axle in the collet, although in brass rather than steel. I think it also adds rigidity to the arbour when force is applied to the tyre. I am thinking about making a similar MT2 arbour with adjustable plates to hold various sizes of wheel.
Its good to here that the Markits p4 axles were right with the back to back of their wheels
Did you use a Dial gauge to check the running of the wheel on the arbour or just bolt tightly to the arbour as the arbour should be perfectly square to the cut?
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hollybeau
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Re: Has anyone used the society's wheel form tool yet?

Postby hollybeau » Tue Feb 14, 2023 7:31 pm

Hello Jeremy. Yes I did use a dial gauge. Even with the face of the mandrel perfectly true (in theory at least) there was some slight "in and out" variation seen on turning. The three bolts helped to reduce that to virtually zero. I put this down to some imperfections on the back of the Markits wheels. Normally I would have rubbed them with their backs down on some fine wet and dry on a flat surface but this was not possible because of the boss.

Bryan


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