Making your own wheels

Spitfire2865

Western Thunderer
Hello all.
Wondering if anyone has any experience making their own loco wheels.
As some may know, I have a desire to build an early American loco to modern G3 standard and unfortunately there are no usable wheels currently on the market.
My idea is to do it as the prototype, having a cast or machined spoked center with a machined tyre shrunk onto it. The major pitfall for me is I have no access to machine tools, although I should be able to shrink a tyre myself with the household oven or bbq by my very rough calculations.

My question then is does anyone know of any good small run manufacturers who would be able to take a design from master to finished parts?
I would idealy like to not blow the entire budget on wheels but I realize they would be a good portion of the cost.
 

Brian McKenzie

Western Thunderer
Trevor,

Have made similar American loco wheels in this manner . . . .

Rogers driver.jpg

. . . . . starting with templates cut from cereal packet card, to obtain the curvaceous cross-sections of spokes and inside of rim (which were cast hollow in the prototype). The templates are scanned for preparing CAD profiles - used to create a 3D solid model. Then exported as a STL file for 3D printing in wax, for use in the investment casting of brass.

The photo below shows a 60inch dia driver on Virginia & Truckee loco No.18 'DAYTON'. In recent months it has been moved from Virginia City to the Nevada State Railroad Museum at Carson City. If you could persuade a volunteer there to prepare some shaped templates and list some depth 'front-to-back' measurements of this wheel - or from any other loco of interest - I could get busy with the mouse.

-Brian

V+T no18 Dayton_4057a.jpg
 

Ian_T

Western Thunderer
Hi Trevor,

Most of the 'custom' wheels I've seen have either been fabricated or cast from prepared patterns. Mark Wood here in UK makes very nice wheels castings (using lost wax methods) but they are fairly pricey. In terms of fabrication, the best/simplest method I've seen described is by Kozo Hiraoka in his Shay/Climax/Heisler book. He makes the various components and silver solders them together using a backplate (which is eventually turned away).

However, not having a lathe seems to preclude these solutions - and your obvious knowledge of 3D design and printing suggests an approach similar to Brians. Mark Wood will turn/finish his castings for you - but it's not cheap I'm afraid...

Regards,

IanT
 

Overseer

Western Thunderer
Before I had the pantograph mill I made driving wheel patterns from 3mm aluminium sheet - mark out the spokes, rim etc with a scriber then drill between the spokes, cut out with a jewellers saw and file to shape. You might need to use thicker sheet for G3. Cranks were built up with brass cut to shape and pinned/glued on, with fairing in using Miliput. I then had them cast in brass by a commercial jewellery caster. You will need to have someone turn the centres to fit the tyres.

I have also done trials doing the same thing with wax slabs instead of aluminium. Jewellers suppliers sell packs of wax slabs in various thicknesses specially for carving into whatever shape you want then lost wax casting. Files and saws work fine with the wax and it can be 'welded' together. Saves the cost of a rubber mould but you would need to make one fore each wheel.

These suggestions are probably too low tech for you but they are relatively cheap, and I find making things by hand enjoyable.
 

JimG

Western Thunderer
I would go along with 3d printing the spoke centres - either printing in resin for lost wax casting, or printing directly in metal. I would then get someone to turn and fit steel tyres to your cast centres. That might cost a bit but you should get a good job.

As for shrinking the tyres onto the centre, I'm not sure if you would require this. I've fitted steel tyres onto brass centres in 1:32 scale and I had the centres as a push fit into the tyres, then locked the tyres to the centres with two tapped keys (small BA screws) on each wheel across the centre/tyre joint to lock the tyres in place. I went with this method since I wanted electrical continuity in the wheels but some others might advocate the use of a cyanoacrylate glue to fix the tyres to the cntres. I note that model engineers are now using cyano glues to make axle/driving wheel joints so should also do tyre joints as well.

Jim.
 

Steph Dale

Western Thunderer
Jim,

I'm not sure about using cyanoacrylate 'superglue' adhesives as they're not moisture or oil tolerant, but high strength retainer such as Loctite 638 is certainly used for such engineering applications...

Steph
 

JimG

Western Thunderer
Steph,

I used a sort of generic term since I couldn't remember the Loctite number of the glue to use. :)

I also forgot to add that Mark Woods does form tools for a load of scales including G3.

Form tools

His prices are good for what they are. I've ordered up a batch of form tools for S scale from another supplier and the unit price of that batch was a bit higher than Mark's price for my ScaleOne32 form tool.

Jim.
 

Spitfire2865

Western Thunderer
To give a bit more context.
The creation of the wheel master isnt an issue as Im fairly proficient with 3D cad and 3D printing.
The issue is making the finished part.
I wanted to shrink the tyre on because I dont want to deal with glues and I rather like the idea of doing it that way. I realize the tolerances required but by my calculations I should easily be able to get .5mm expansion from the oven so just enough to slip over and hammer on a tyre, however I wouldnt be able to true up the tyre afterwards.

Id also like to design it to use Slaters type axles as I find being able to easily take the wheels off if needed very useful, plus I hate struggling with quartering.
This is why I had the idea of CNCing the centers as I could have a finished center hub that only requires tapping for the crankpin which is easily done by hand.
Ive had a look around online and put my idea out to a couple companies to check on costs for the center hub.
I could have each hub 3D printed IN metal but Im unsure if itd be strong enough to take the shrinking, tapping, or tolererance fits.
The not having a lathe bit really is my stumbling block, and I know no one who does.
My work has a machine shop but its not something I have access to.
 

bambuko

Western Thunderer
No experience as such, but perhaps an inspiration from 1948? (by "LBSC")

43785077545_60ac8efc87_b.jpg
 
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