Making a pattern for a small model locomotive coupling.

[Tony Bird]

Hi,

For many years I have used a commercial made injection moulded GRP coupling for my garden railway models. Its is a very simple coupling which I modify to use on the smaller models I make and play with. I think the moulds locating pins are worn as the recently bought couplings are a bit misshapen. So I decided to make some patterns so resin ones could be made. The pattern is very simple but there might be some interest in how I made them.

First a rectangle of brass was machined on a wax chuck.

For the second machining a supporting piece was used.

Semi circles were marked on both ends of the brass and semi circular ends were filed.

Both ends filed to size.

The semi circular ends were parted off.

The parted off ends.

These ends were hard soldered to brass plates.

The two patterns were machined to thickness together on a wax chuck.

Their ends were machined using a 4-jaw chuck.

The two patterns cleaned up along with the coupling I hope to replace.

I now need to learn how to make the moulds and cast the resin or maybe I will give it to someone else to do.

Regards Tony.