Machining Delrin Round Stock?

It was a joke, playing off of what Wreckwreck posted.:) I agree - cut it nice or live with it.
 
Thinking that some of our guys may not wish to mess with grinding a tool to cut Delrin, I decided to try using a carbide tool to compare results. I used one of the most popular turning tools in existence, a SCLCR tool with a CCGT 22.51 Aluminum cutting insert. This insert is very sharp, has an aggressive positive rake at the tip and it cuts very well, indeed. I didn't have a 22.52 (1/32" nose radius) insert handy to compare but even the 22.51 (1/64" nose radius) left a nice finish when fed a bit slowly. It will also rough as aggressively as your work holding situation allows.

An SCLCR tool normally takes CCMT inserts but will fit the CCGT inserts as well. The aluminum cutting inserts work a treat for aluminum but I can confirm they also do Delrin quite nicely. The 1/64" nose radius cuts fine but finishes a bit spirally for my taste; for finishing, a 1/32" nose radius would be better in my opinion.

Is it better than HSS? No, it is not better than the tool I would normally use but then again, I had to grind it. This took me all of 30 seconds to put an insert in the tool. For the guy who doesn't turn Delrin often, this would probably work just fine. If you must cut tight to a shoulder a smaller radius works but for general work and finishing, the 1/32" nose radius insert would be better. Just be sure to get the insert intended for aluminum.
 
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I don't turn the stuff but just wanted to say thanks for the question being asked & everyone giving the advice. I've found this thread to be very interesting.

I've only turned PVC tubing after heating to form close to the size needed. I consider that a big pain in the butt & this stuff sounds worse.
 
kingmt01 said:
I've only turned PVC tubing after heating to form close to the size needed. I consider that a big pain in the butt & this stuff sounds worse.
Click to expand...

Of all the plastics I've machined (pvc, uhmw, hdpe, nylon, acryic, ABS, polycarbonate, etc.), Delrin is the BEST! It cuts very freely (I equate it to free machining brass), and leaves a very nice surface finish. If you got the impression it is worse than PVC, I haven't made myself clear. :confused:o_O:rolleyes: It is nowhere close to being a pain!
 
I agree with aeroHAWK - Delrin is like machining firm butter, while Polyurethane is like machining the 1018 of the plastic family. Delrin can make me look like I actually know what I'm doing!
 
+1 with Aerohawk. I have machined a lot of Delrin over the past decade, including parts as small as 1/8" diameter and have never found it to be particularly picky about tool grind. I used HSS tools and kept them sharp. Even with a zero radius tool, I would have nice finishes. I don't ever recall having a problem with melting.
 
I have found this thread very interesting too. I have a small project coming up that will require me to create a small push-handle for the end of a small shaft, out of Delrin. One question as another of the beginners here, is what is a Swiss-type lathe? What are the defining characteristics of it?
 
Swiss lathes are ultra-precision, very high-dollar CNC lathes. They are used for precision manufacturing of complex parts for many industries from almost any material, including plastics. I don't presume to know what Wreckwreck was referring to but this is what I was joking about:

http://www.3dmedicalmfg.com/capability/swiss-style-lathe/

Check the video at the bottom of the page. Probably won't score one of these on Craigslist anytime soon.
 
mikey said:
Swiss lathes are ultra-precision, very high-dollar CNC lathes. They are used for precision manufacturing of complex parts for many industries from almost any material, including plastics. I don't presume to know what Wreckwreck was referring to but this is what I was joking about:

http://www.3dmedicalmfg.com/capability/swiss-style-lathe/

Check the video at the bottom of the page. Probably won't score one of these on Craigslist anytime soon.
Click to expand...

I'll bet a guy could make some nice brass kitchen drawer pulls with one of those in his garage. :D

I turned and threaded some Delrin yesterday just for grins. (Not on a Swiss lathe, though.) Used HSS inserts and they worked well. I did discover that if you cut an unsupported 1" long 1/4-20 thread in Delrin, the outboard end threads will be a lot shallower than the inboard end. Go figure. ;)

Tom
 
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