GearHeads Corner

General Category => CNC Machine mechanical questions => Topic started by: marklazarz on April 21, 2016, 09:10:12 AM



Title: Using End Mill as a Drill
Post by: marklazarz on April 21, 2016, 09:10:12 AM
Just finished a Brian Law clock (clock 24) and I used a 1/8" up spiral router bit to do a lot of the machining and noticed something interesti ng.  All of the 1/8" holes I programme d as drilling tool paths were slightly oversized, yet the larger holes I programme d as profile tool paths using the same cutter were the correct diameters .  I took the cutter and measured it and checked it for distortio n and everythin g seemed fine.  I then put the router bit in a drill press and drilled some holes and they were all slightly oversize (say 0.001" or so).  I then put a 1/8" drill bit in the drill press and drilled a hole - perfect.  Has anyone else noticed this phenomeno n?


Title: Re: Using End Mill as a Drill
Post by: BobL on April 22, 2016, 07:57:38 AM
Mark;

Congratz on finishing your Brian Law clock, post a picture if you can, love to see it.  As to the oversize drill hole, could it be you have a slightly warped router bit or maybe it's the spindle itself?


Cheers
Bob




Title: Re: Using End Mill as a Drill
Post by: marklazarz on April 22, 2016, 12:42:01 PM
Mark;

Congratz on finishing your Brian Law clock, post a picture if you can, love to see it.  As to the oversize drill hole, could it be you have a slightly warped router bit or maybe it's the spindle itself?


Cheers
Bob




Checked for warping, dimension s and runout.  Same results on drill press so it must have something to do with a hole being drilled with a flat bottom cutter.  I will post a photo of the clock on the "Ticker" board when I put the finishing touches on it.


Title: Re: Using End Mill as a Drill
Post by: Nate on April 22, 2016, 03:25:13 PM
Quote
Same results on drill press so it must have something to do with a hole being drilled with a flat bottom cutter.  ...

That, or chip clearance .  (Square nose bits are known to wobble when plunge cutting like that though.)


Title: Re: Using End Mill as a Drill
Post by: marklazarz on April 23, 2016, 08:17:09 AM
I think Nate is correct.  Slight wobble with no guiding point would be my best guess.


Title: Re: Using End Mill as a Drill
Post by: ArtF on April 23, 2016, 07:33:27 PM
Sounds logical to me..

Art