Sujet : Re: A big ol' chunk of delrin
De : muratlanne (at) *nospam* gmail.com (Jim Wilkins)
Groupes : rec.crafts.metalworkingDate : 21. Apr 2025, 01:51:53
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vu44rs$vrlu$1@dont-email.me>
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"Snag" wrote in message
news:68053d6b$6$5278$882e4bbb@reader.netnews.com...On 4/19/2025 11:41 AM, Bob La Londe wrote:
On 4/18/2025 6:45 PM, Snag wrote:
Since no one currently has X axis leadscrew nuts available for my RF45 clone mill , I must make one . So I ordered a piece of acetal/ delrin . I've been studying videos of heat forming a nut to your leadscrew, all looks fairly easy . I'll use a piece probably about 2X2X3 for the nut . I bought a chunk that turns out to be 2 1/2X3X12 ... just in case it takes more than one attempt .
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Let us know how it goes. I first heard of heat forming Delrin nuts right here on this group years ago. For my application I went with a spring loaded anti backlash Delrin nut from DumpsterCNC back then instead. I don't think DumpsterCNC is still around.
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This is interesting , your text did not show up in the post over on
e-s but it did here on blocknews ...
Now to the meat of the sammich . I have been out in the shop all
morning making a tap* to match - pretty closely - the leadscrew on the
mill . The plan as of right now is to tap the hole I have made in a
chunk of that delrin . I'm hoping for a tight fit so I can heat the
leadscrew to finish forming the threads without splitting the nut . If
it's loose I'll slice the nut in half and heat/clamp to finish forming
the threads . If it's too tight to thread on I can split one side to get
it on the leadscrew and heat form from there .
*I still have to form the flutes on that tap . I'm thinking a 1/2 or
3/8 ball end mill With the tap held in a 4 sided collet holder or maybe
do 6 flutes since this tap is just under an inch . I used a chunk of
1.25" rebar for the tap since it was the closest in size to the finished
product and I hate wasting material . I'm not planning on hardening it ,
this will likely be the only time it will ever be used .
I also have 9 inches of 2 1/2 inch square aluminum stock coming to
make a holder for the nut . Probably only use a couple of inches , but
hay , I'll have stock for other projects down the road .
shop break
Well , the tap idea isn't going to work , I guess I'll stop and
rethink my approach . But at least I was outta my wife's hair for the
whole morning !
-- Snag--------------------------------I did see Bob's post on E-S.For a single use tap you could flute it with one corner of a square ended endmill, perhaps one with dull corners that you beveled sharp again, using your endmill fixture at the back relief instead of the cutting edge angle. If a hard spot in the rebar dulls it you can regrind it the same way. It's my go-to endmill for roughing steel of uncertain parentage and upbringing.A tap drill size pilot plug on the tap may help keep it centered and straight.
In aluminum at least unhardened steel dulls quickly.
I will soon try making a tool from a scrap of broken rock drill pipe, and see how easy to saw and turn it is.