HDPE Milling Gears

I spent the last few weeks working on these parts for a client and enjoyed working in HDPE. It’s a breeze to mill and single flutes devour it. I would recommend you give it a try if you haven’t and enjoy making some parts in it.

I used a 6mm single flute for facing, a 1/8" single flute for the bulk of the milling, and a 2.5mm single flute for getting into the small crevices the 1/8" couldn’t get into. My setup is a Shapeoko 3 w/ HDZ w/ steel-core belts.

Milling Parameters
6mm single flute
DOC = 1.27mm (from stock to desired thickness)
WOC = 3mm (pretty standard as I find a 50% stepover ideal for most soft materials.)
Chipload = 0.175mm (not a problem, could have gone faster)

1/8" single flute
DOC = 4mm
WOC = 1.7mm
Chipload = 0.075mm

2.5mm single flute
DOC = 2.5mm
WOC = 1mm
Chipload = 0.065mm

Photo of my setup (Gator clamps work great)

Video of the milling

Photo of the final parts and endmills used

Bucket of HDPE snow


Those have to be the weirdest gears I’ve ever seen. :smiley:
Look really fine.


Will you be melting down the HDPE and recasting it?

OK now that you showed us the gears, what type of usage requires such deep narrow groove? I can’t see two of those trying to drive one another without interfering. Great looking gears BTW.

Yes, @luc.onthego and @CrookedWoodTex, you’ve pointed out the problem with these. They aren’t actually gears, I just don’t know what else to call them. The teeth are not involute and wouldn’t intermesh well at all. My client just hasn’t shared what they’re for and I haven’t asked, although he said he’ll show me what they’re for once he gets them set up.

@WillAdams - No, I will not. Even though I have equipment at work that would let me do that, I can’t do it well enough to my desired tolerances and it’s not expensive enough to be worth my time.

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I wonder if this could be some kind of giant encoder wheels, to be used with a light emitter & light sensor positioned across the edges of the “gears”.

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[quote=“Julien, post:6, topic:19358”]
some kind of giant encoder wheels
[/quote] @The_real_janderson

I’ll go out on the limb and say they are crimpers for the edges of empanada pockets. :smiley:
PS. Its lunchtime here!


What about a wheel that spins and hits a stationary card to make noise like many of us have done on the wheels of our bike when we were kids so our chopper/banana/Mustang bikes would sound like a motorcycle.


Nice HDPE work @The_real_janderson!

But… How did you NOT ask? My Sunday is ruined because I need to know. :wink:

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@The_real_janderson - quick question why is you DOC much higheer for smaller MM endmills would you mind explaining, i.e. your 6mm DOC was 1.27 and your 2.5mm is 2.5mm i would have thought that it would be the other way, have yet to mess with HDPE, might be a silly Q so sorry for asking


His 6mm was just used to face the stock to desired thickness. That DOC was the amount he needed to remove.


I know, I know. You’ll just have to be patient and wait with me to figure out what these are for. :slight_smile:

@Sherpa - Yep, like Neil said. I was just using the 6mm to face the stock so I only needed it to go down that far and no further.

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