Turning insulated wheels - an experiment.

Unless you're building split framed chassis locos, are stuck in the past using the 3 rail system or your locos have their own onboard power source you will need the wheels on one side of the chassis to be electrically insulated from the other. I enjoy making my own wheels, but so far I haven't had to worry about insulation. I have noted that epoxy is used as an insulator when making split axles for split framed locos, and I wondered if the same type of glue could be used for making insulated wheels where the tyre is insulated from the centre.

For no better reason than it felt right I decided to make some 7.2mm dia. wheels. I started with a length of 10mm dia. CZ121 grade brass. To make a blank for the tyre I drilled and parted off a ring with a 6.5mm bore 3mm wide. From the same material I turned one end down to 5.7mm dia. 5mm long, with a groove near the end (for glue, perhaps not neccessary but I didn't think it would do any harm);

Using quite a lot of epoxy (Evo-Stik Epoxy Rapid, all I could find locally) I glued the tyre to the centre making sure that the gap between the two parts was fully filled, and left the tyre and blank in a V block to set for a week or so. Note the gap between the tyre and centre;

I left a gap of .4mm, I'm unsure if this is about right or whether I could get away with less. Once the glue had set the job was faced off then the top turned down to 8.9mm (finished flange dia. plus .1mm). With a parting off tool the width was reduced to 2.2mm, then a step turned to 7.3mm dia. (tread dia. plus .1mm) leaving a .8mm wide width for the flange;

With a NEM 310 'N' gauge profile tool the lathe was set to 150rpm and the wheel profile formed;

I parted each wheel off overlength, then held them in a step chuck to finish to length;

Here's one faced to 2mm wide;

Each wheel then had its face profiled, again held in the step chuck;

In the photo above are the two insulated wheels (lower) plus 2 solid brass uninsulated wheels.

As the tread is only glued in place I played safe by only taking light cuts and working very gently! In hindsight it might have been wise to do a destructive test by taking bigger and heavier cuts to see if the glue would fail.

This technique so far seems to work ok on smaller wheels but I'm not sure that it would work on larger wheels where the turning forces are greater, or harder materials than free machining brass. More experimentation required!

Of course the next job will be to build a working chassis to test these, then of course I'll need to build a body to sit on that chassis...

Paul.

Grounded van bodies 14.

Coach bodies this time, 4 of them in fact. I photographed these today whilst visiting the Wells & Walsingham Light Railway. I know little about the bodies, I believe that the one next to the platform has been refurbished inside and converted to a craft room. The staff were busy going about running a railway so I didn't want to ask inane questions about coach bodies. I did note that some had the remains of wallpaper inside (along with a lot of rot and big holes in the floor), and at least one had a kitchen area. So they could have been holiday chalets? Whatever they were, I'm sure that the railway will make good use of them.

Here's the first body, built in 1880 by the GER, located next to the platform;

This one sits close by, behind the signal box;

Two more sit on the other side of the car park. Here's the one on the left;

From the other side;

And the right hand body;

Kitchen end, there's still a cooker and sink inside;

Note the vent! Yes it is a Castrol GTX can!!

I make no apologies for the photo heavy post, just look at all of those textures.

Paul.

Sorting my Saltford Models 'Audley' class.

As I've mentioned before, I recently aquired a Saltford Models 'Audley' class loco. It arrived with a broken rear bufferbeam, no couplings or cab roof and the cab rear separate from the body.

The first job was to sort out the rear bufferbeam, an easy fix. I just prised off the old one, which was made easier by the glue (epoxy) having failed between the brass frames and the plastic and made up a new one from .030" plasticard.

A new roof was rolled from .010" brass, with rainstrips from .33mm brass wire soldered in place. I tinned the end of a length of wire, soldered the wire in place with an overhang at both ends, then trimmed the excess wire to length once I was happy with the joint.

I tried a new method when cutting the roof to size. I marked out the brass then scored the sheet with a 'scrawker' type plastic cutter, the type with a 'v' shaped edge. Once a deep line is scored in the surface the sheet can be snapped over the edge of the bench, just as you would for plasticard. Which works rather well.

The cab rear and roof are just superglued in place.
Couplings are my own turnings, which look similar to the type shown in an old Saltford advertisement that I've seen.

So, now its in one piece. I shall probably leave it like this for now, unpainted.

Paul.