Turning Delrin Plastic: Ultra-Versatile Lathe Stock

I seriously don’t know how anyone can run a household without a metal lathe. I’ve machined so many parts, fasteners, and tools on my lathes, It’s hard to remember all of these projects. Just this week I got sick and tired of the clutch safety switch on my 2001 Dodge 3500 truck, and I fixed it quickly with some delrin plastic, and my 1955-built Logan Model 1922 metal lathe.

Here’s how and why I fixed this safety switch:

About Delrin Plastic

Delrin plastic (scientifically known as Polyoxymethylene, or POM)  is a hard but free machining plastic that is used to manufacture electronics components, eyeglass frames, plastic bushings, and many other items. It’s a great material to have on hand in a machine shop because you can make electrically insulated high-strength parts quickly and easily with your lathe, mill, or other machine tools. I ordered a selection of Delrin plastic from Online Metals about 10 years ago, and have used it for many different applications and projects. If you have a metal lathe, you need to keep a supply of Delrin on hand in various diameters, it’s invaluable!

Machining Delrin Plastic

Here’s what’s great about machining Delrin:

  1. You can go very fast- large and fast feeds and speeds
  2. Chips stay together and are easily removed from your machine
  3. Your tools won’t dull (practically not at all)
  4. You don’t need machining fluid
  5. The surface finish looks great
  6. Tools that cut steel or aluminum will generally work very well with Delrin- no re-setup or special tooling!

I’m sure there are other things I’ve missed here about Delrin, but I really love this material, and it’s my go-to plastic for general projects. It worked great for the clutch safety switch spacer, and with a notch cut in the spacer, Delrin’s flexibility allowed me to slip it over the clutch shaft, no need to completely disassemble the clutch pedal assembly. Yay.

Above you can see the safety switch shim in place, just before I released the spring loaded switch against it which holds it in place. Now I can truly enjoy my Dodge- the sound of the Cummins Turbo Diesel, the Jacobs exhaust brake, the NV-5600 6-speed transmission, life is GOOD.

Do you use Delrin for machining projects? I’d love to hear your experiences!


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