From: Snag_one@msn.com
On 4/21/2025 10:19 AM, Clare Snyder wrote:
> On Sun, 20 Apr 2025 22:42:39 -0500, Snag wrote:
>
>> On 4/20/2025 7:51 PM, Jim Wilkins wrote:
>>> "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 .
>>>>
>>>>
>>>> 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.
>>>>
>>>
>>> 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 !
>>
>> 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.
>>
>> -----------------------
>>
>> I'm thinking at this point that I might try threading the inside with
>> a boring bar and a cutter that is close but narrower than the groove
>> width of the thread . This will make it necessary to split the nut and
>> hot form the thread . My main concern about splitting the nut is whether
>> the halves will fuse together into a solid unit during the forming
>> process . I'm once more stepping off into unknown territory ... but you
>> know what they say "keeping learning will keep you young" .
> Don't be a wuss -chuck it in the 4 jaw and single point it. If you
> grind your tool right you won't even need to heat form it - - - -
>
The problem with that is that I'm not certain what the thread profile
is - probably acme but ... I was just thinking that I can make an
impression of the leadscrew , wax might work or clean the leadscrew well
and apply a release compound and mold one out of JB weld ... and use
that impression to grind a cutter . That piece of plastic is dialed in
on my 4 jaw , and ain't coming out just yet .
--
Snag
We live in a time where intelligent people
are being silenced so that
stupid people won't be offended.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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