Making a wheel profile tool - turning the master.

Despite owning several wheel profile tools bought from eBay I thought it might be fun to make my own. First of all I did some research, and found this article on the Manchester Model Railway Society website. The gist of it concerning making the profile tool is; turn a wheel to the correct profile in silver steel, convert that into a cutting tool, use that tool to cut a negative profile into another piece of silver steel, convert that into your forming tool. Silver steel can be easily worked then hardened and tempered making it ideal for making cutting tools.

I decided to make two tools, one to 2mm Finescale standards and one to NMRA RP25 Code 72, to cover both my 009 work and any future delving into 006. The relevant standards can easily be found online.

First of all I aquired some 16mm dia. silver steel, and turned the end to the basic dimensions of the wheel;

Then the 3 degree tread cone angle was turned, using my compound slide. There are two ways to get the correct angle for the flange (about 20 degrees), either by setting the turning tool to an angle to cut the flange angle at the same time as the tread is being turned, which is what I did on the 2FS wheel, or using the compound slide set to 20 degrees as shown below on the Code 72 wheel;

Once the basic form was finished a 5.1mm hole was then drilled in the centre and the wheel cut or parted off. Then using a watchmakers step collet the back face could be faced to length;

A simple mandrel was used to hold the wheels so the flange could be rounded off with a file and the wheel polished to a fine finish;

Both wheels ready to be made into cutters;

A centre line was scribed onto the back face and a cutting edge filed to just below the centre, to give some cutting rake (clearance);

Once I was happy with the shape the edge was ground, starting with fine oilstones and finishing with an Arkansas stone;

Then both cutters were hardened, by heating to bright red with a blowtorch and quenching in water, then tempered in the kitchen oven set to 200 degrees for 45 minutes to an hour. I then tickled up the cutting edge again with the Arkansas stone.

To use the cutters I made simple holders from 8mm square steel, drilled and tapped M5.

The next step will to use these masters to make a pair of forming tools.

Paul.