View Full Version : Forming Acetal gears.

The Artful Bodger
09-16-2010, 12:21 AM
Some weeks ago I showed how I had heat formed some lightweight ABS gears and Evan tried the same with Acetal. If I recall correctly, Evan tried heating the blank but the forming failed.

Now that I have some black plastic which is probably not Acetal but I tried it anyway. It is much harder than the ABS was and there was no sign of it forming without added head.

This time I put the blank on an arbor in the chuck and mounted the steel gear on the tool post, I pressed the gear against the rotating blank which started the familiar rumbling sound then I put my heat gun to the edge of the gear and when the rumbling eased I advanced the feed and repeated until the teeth were formed at full depth. Success!

Well formed teeth that appear to be full strength but I can not get rid of the hairy edges!:mad:


Tony Ennis
09-16-2010, 12:23 AM
Load the 'hairy' gear with grease and proclaim victory.

09-16-2010, 12:32 AM
So, would that be hobbing or forming? :D

09-16-2010, 03:32 AM
Yea, Call the hairs 'Oil wicking surface' or something :)

Nice job.

The Artful Bodger
09-16-2010, 06:33 AM
Yes, obviously the technique needs a bit more development!:rolleyes:

Dan Dubeau
09-16-2010, 11:17 AM
So, would that be hobbing or forming? :D
fobbing, or horming

09-16-2010, 11:36 AM
Would the hairy gears and unusual technique make this guerilla or gorilla machining then?