After Covid hit, I had a really hard time sourcing certain parts. So I decided to make them. I bought a 3D printer & a Mill and I haven’t looked back since. In the spirit of keeping this hobby going, I’m sharing all the work and designs. I use OnShape for all my 3D designs. You can export these drawings to STL files, import them into your favorite 3D printing software ( I use Cura) and 3D print copies yourself.


Model T Starter and Generator Upper & Lower Insulators

There are various forms of these insulators you can get from the vendors. The paper ones in my opinion are total junk. The fiberglass ones work well, but they are out of stock most of the time and very expensive. So, the next best thing is to 3D print them using PETG, a very durable plastic impervious to oil and gas and very strong. You can export STL files and print them yourself.

Generator lower brush plate insulator
Generator upper brush plate insulator

All of the Onshape files are here:

Model T Starter Post insulators

The Starter Post Insulator was also drawn in OnShape. I also 3D print this using PETG and aggressive heat settings to add to its strength. Its here:

Post Insulator
3D printing multiple Post insulators on my Ender 3 Pro. These took about 3 hours to print.

Model T Copper Starter Post

Most of the vendor are selling starter posts made out of Bronze. That’s ok, but Copper is MUCH better, especially when you’re trying to cram as much of that 6v battery power into the starter as possible. I start with at 3/8″ copper rod, and then thread about 1″ using a 3/8″-16 die on my lathe. Then I cut them to size w/ a hack saw. Then its over to the mill where I drill a 1/8″ hole and then mill a 3/32 slot for the field coil winding.

Starter Post


After loosing my speedometer gear multiple times due to a broken shaft, I fixed the shaft and designed a Stewart 2301 speedometer gear, also in OnShape. This gear was quite challenging to get right, but it works flawlessly. Again, I 3D print it in PETG.

Stewart 2301 Speedo gear 3D printed from PETG Plastic

Here is that part: