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LTM 51 in HO

Drive unit - coupling rods

The coupling rods as supplied with the kit were simply horrible. Too thin, too high, and first and last axle hole too big. They also lacked the detail the original had. So I decided to have a go at it myself. I made a design in Fusion 360, which I was learning at the time

A rendering of the 3D Fusion model

I ordered three 3D prints at Shapeways in three different materials to see how it would work out.

First print was in "White Natural Versatile Plastic".

Costs $5 per set of four. Result: useless. There is simply no detail, no matter how much work I would put in.

The second set was printed in Smoothest Fine Detail Plastic. Well that came out nicely! The setback of this material is that is brittle and cannot have any kind of serious mechanical load on it. So to turn these into working coupling rods I will have to make a mold and make cast replicas. This might just work.

The same set but now sprayed with a base coat to highlight the details. It really looks good apart from a bit of riboning as a result of the printing process. A bit of sanding will cure that.


The third set was printed in aluminium (aloominoom for US dyslectics). At first sight the result is horrible but contrary to the first set in White Natural Versatile Plastic I could discern a reasonable amount of detail.

Despite my initial disappointment I decided to to have a go at cleaning it up. First operation was sanding it down until the structure on the front was smoothed out.

Then a bout of careful filing took care of the sides


It took me two hours but in the end I had four reasonably looking coupling rods.

A comparison with the rod originally provided with the kit. Although not perfect it certainly is an improvement.