For split frame collection to work you need solid metal wheels fitted with stub axles, which locate in an insulated bush. I don't have a form tool for producing wheel profiles, and to turn wheelsets with a form tool you will need a very rigid machine with a lot more power than my Unimat has. So my solution is to use the tyres from Parkside Dundas wagon wheels pressed onto turned brass centres.
For this experiment I used Parkside's 7mm N gauge wagon wheels. To start I seperated the tyres from their plastic centres. Then, after measuring the inside dia. of the tyre (6.36mm) I turned a length of 7mm dia. brass approx. .05mm oversize (6.41 - 6.43mm), the width of the tyre plus the width of my parting off tool. A .5mm long x 2.5mm dia. step was turned onto the end as well, copying the plastic centre. After drilling a 1.4mm hole for the axle the tyre could be pressed onto the new centre;
The parting off tool was positioned by lightly touching the tool on the flange back face, then the saddle could be locked and the wheel parted off;
Here's one brass centered wheel next to an untouched Parkside example;
Stub axles are 1.5mm steel. To fit the axles I opened out the 1.4mm holes with a 5-sided cutting broach until the axle would just start to fit. Then the axles could be pressed in place on the lathe. I did try drilling one wheel 1.5mm, but the hole turned out slightly oversize.
Axle muffs are Acetal, turned down to 1/8" (to suit readily available gears) and drilled first to 1.4mm then to 1.5mm. One was parted off at 7.5mm long, for OO9, and the other at 4.5mm, for OO6 (18" gauge);
I don't have a use for these two axles, these are just test pieces.
Spindle speeds for brass were 2000rpm for turning and drilling, 365rpm for parting off. For Acetal the machine was set at 1600rpm for all operations. All work was cut dry.
Paul.
Nice, I just have to do the same but spaced to 12mm (for 00n3) Then I have something prototypical to pull my Rye and Camber coaches at last.
ReplyDeleteThanks Mark. If you need any help don't hesitate to ask.
ReplyDeleteThere's an unbuilt Nonneminstre Models Rother Ironworks coach in my secret n.g. stash. I wish that I'd bought the other Nonneminstre Rye & Camber kits at the time.
The only OOn3 loco that I own is a converted A1 Models Ruston 48DS, based on the example preserved at Irchester.
I bought my Lathe for making splita xle wheels, though I'm starting out with lost wax cast centres (3D printed by Shapeways) which can then be turned to match the tyres as above.
ReplyDeleteNow that sounds interesting. 2FS?
DeleteI now have a few wheel profile tools to play with, which are available from Carbide-Solutions via their eBay shop.