From: Snag_one@msn.com   
      
   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" .   
   --   
   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)