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5/26/2017 2:01 pm  #1


slipping endmill bits??? how to avoid this a second time

OK some very awesome stuff from broken arms i got the full package deal with all of the goodies inside yesterday very very fast shipping only 2 days high five to B.A.A. for such fast shipping!!
    so anyways this is my first ar build and 80%lower everything was going real good taking my time on everything got down to the 4th plate was using the 3/8 end mill had made several pass slowly making my way down drooping a 1/4 inch at a time started to make my second to last pass set at a max depth of 1.200 so that way my last pass would only be taking .005 off but somewhere along the way the bit had fallen down digging a 1.500 +\- on one side you can see where it was a slow drop down starting at 1.220 and by the time i saw shaving falling from below the reciver it had gone to 1,5 and the chuck was still very tight i had to give it a bit of force with the chuck key to take it losse.
     so my question would be this how could this be prevented in the future and was there some way to possibly modify the shank on the bit so that its not so smooth and prone to falling?

 

5/26/2017 2:21 pm  #2


Re: slipping endmill bits??? how to avoid this a second time

and this will be my 2nd post that way i can upload a pic

     Thread Starter
 

5/26/2017 2:22 pm  #3


Re: slipping endmill bits??? how to avoid this a second time

http://i86.photobucket.com/albums/k102/dasnatester/IMG_0179_zpsme2kmq36.jpg

     Thread Starter
 

5/26/2017 3:30 pm  #4


Re: slipping endmill bits??? how to avoid this a second time

If the chuck was tight, I would assume that the quill slid down.

I would tighten the quill lock, then try to move the quill to see if thats where the issue is.
 

 

5/26/2017 5:03 pm  #5


Re: slipping endmill bits??? how to avoid this a second time

ive just got a cheap little ole 12" drill press as far as the quill goes i was haveing more of a riseing issue out of it where as in id set for a depth of .625 and after several times it would go up to like a depth of .600 and id have to relower it but that was with the regualr drill bits which in the case of not wanting to drill to deep it isnt such a bad problem to have 
idk maybe the end mill bit acted differrtly wuth the drill press never had played with em before on it

     Thread Starter
 

7/28/2017 9:29 am  #6


Re: slipping endmill bits??? how to avoid this a second time

Mike wrote:

If the chuck was tight, I would assume that the quill slid down.

I would tighten the quill lock, then try to move the quill to see if thats where the issue is.
 

Neat trick. Lol I've never experienced that particular problem. But I have to agree with Mike that it is probably an issue with the quill lock loosening probably due to the vibration from milling on a drill press.(I accidentally punched a hole clean through the bottom of a lower due to this.) As far as the reverse problem your talking about I've experienced the end mill slipping due to not tightening the chuck enough and trying to "muscle" the cut rather then letting the tool do the work. I'm no expert but this is what I've observed in my limited experience.

Joe

 

10/30/2017 11:14 am  #7


Re: slipping endmill bits??? how to avoid this a second time

Mike wrote:

If the chuck was tight, I would assume that the quill slid down.

I would tighten the quill lock, then try to move the quill to see if thats where the issue is.
 

I'm with Mike.  I had this happen twice - both times it was getting late and I was getting impatient.  Tried dropping the chuck too much. My humble recommendation is to just go way slower, and only remove a 1/16th to 1/8th at the bottom of the pocket per pass. I think mine actually dug in and burrowed down, pulling the arbor/quill down.  Afterward, I froze the arbor & chuck overnight, then hit the quill with a torch before pounding the whole mess back in.  I think I put some loctite on there too, so hopefully I don't need to take it out anytime soon.  Just my 2 cents.

 

4/12/2018 7:12 pm  #8


Re: slipping endmill bits??? how to avoid this a second time

This is an old topic but I just saw it so I'd like to add my solution. My arbor had slipped more than once and was about to lock it in with Loctite sleeve retainer but then I'd never be able to remove it. The solution I found was to use a drill stop and mount it so it just clears the milling plate. Now the drill stop will hit before any damage is done to the receiver. It will however mar the top of the milling plate when this happens.

 

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