Author Topic: Mill Creep  (Read 12742 times)

Offline sshire

  • Full Member
  • *****
  • Posts: 3043
    • LS Editions
Re: Mill Creep
« Reply #15 on: January 04, 2015, 10:51:27 PM »
It's 2015. I thought we had put the "end mill/slot mill" thing to bed in 2013.
In the interest of repetition, here's one more try  In the Colonies, you can buy two types of end mill.Center cutting and non center-cutting. It's rare to see the non center-cutting variety. Both varieties are called "end mills."
I just checked my end mill drawer. 100% center cutting. I'm assuming that slot mill is the U.K. name for center- cutting.
Hopefully, the next time someone posts about milling a slot with an end mill, it won't be necessary to bring this up again unless they are from the U.K. In that case they should be carried of in someone's boot and deposited in the nearest tip.

Best,
Stan

Offline Allen Smithee

  • Full Member
  • ****
  • Posts: 871
  • Mordor, Middle Earth
Re: Mill Creep
« Reply #16 on: January 04, 2015, 10:55:24 PM »
In that case they should be carried of in someone's boot and deposited in the nearest tip.

Well we would, but we'd need an air or sea ferry to get the car boot over to america.

AS
Quidquid latine dictum sit altum sonatur

Offline Alan Haisley

  • Full Member
  • ****
  • Posts: 669
  • Near Clayton, North Carolina, USA
Re: Mill Creep
« Reply #17 on: January 05, 2015, 12:28:27 AM »
From the introductory statement, I'd look to see if the collet was "well oiled" when the error occurred. There are places that need lube and places that need dry and collets are one of the dry ones - as mentioned by Jo.

Mosey, if you have another go at it, take some alcohol or acetone (or your favorite strong degreaser) to the collet, mill, and spindle nose socket before starting. I suspect that all of the creep will be gone.

Alan
Near Raleigh, NC, USA

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6355
  • Surrey, UK
Re: Mill Creep
« Reply #18 on: January 05, 2015, 08:03:02 AM »
It's 2015. I thought we had put the "end mill/slot mill" thing to bed in 2013.
In the interest of repetition, here's one more try  In the Colonies, you can buy two types of end mill.Center cutting and non center-cutting. It's rare to see the non center-cutting variety. Both varieties are called "end mills."
I just checked my end mill drawer. 100% center cutting. I'm assuming that slot mill is the U.K. name for center- cutting.
Hopefully, the next time someone posts about milling a slot with an end mill, it won't be necessary to bring this up again unless they are from the U.K. In that case they should be carried of in someone's boot and deposited in the nearest tip.

Its not the fact they are centre cutting that Jo is on about its the fact they are TWO Flute which for various reasions I won't go into do tend to cut to their nominal size unlike cutters with 4 or more fluted which can cut overwidth.

Offline sshire

  • Full Member
  • *****
  • Posts: 3043
    • LS Editions
Re: Mill Creep
« Reply #19 on: January 05, 2015, 11:57:52 AM »
Jason
Please go into the factors (or physics/geometry) that cause the end mill with more than two flutes to cut over nominal size. It's part of my "apprenticeship." I'm genuinely curious.
Thanks
Best,
Stan

Arbalest

  • Guest
Re: Mill Creep
« Reply #20 on: January 05, 2015, 12:08:34 PM »
I'm sorry some folks don't agree but I rather like the obvious difference in the name "Slot Drill" and "End Mill" and hope the convention continues, over here at least.

The only slight confusion is that you can get three flute cutters and I don't know where these fit in the scheme of things. Are they suitable for slot cutting?

There was a very good description and diagram of why a slot drill is used to cut slots  :facepalm: will someone post the link when they find it. :naughty:

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3818
  • Switzerland
Re: Mill Creep
« Reply #21 on: January 05, 2015, 12:33:38 PM »
A quick internet search showed this to be an endless topic  ::) . The attached document is from the Central Washington University and seems to make sense to me as a novice.

Best regards

Roger

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1031
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Mill Creep
« Reply #22 on: January 05, 2015, 01:31:43 PM »
I find that a two flute Slot Drill is best for aluminium as there is a bigger gap between the flutes for the swarfe to exit.
Ian S C

Offline Mosey

  • Full Member
  • ****
  • Posts: 1583
  • Rosemont, New Jersey, USA
Re: Mill Creep
« Reply #23 on: January 05, 2015, 01:35:38 PM »
The chat about center-cutting v slot milling is interesting, but not germane to my posting. I do find it informative though and will retain the information.
After checking, I find my much-used 1/2" W-20 collet measures .5022" ID, and the roughing mill shank is .4998. I believe that explains most  of the creep.

I have cleaned them both, and the inside of the spindle, as Alan wisely suggests. The spindle of this machine requires oiling, not greasing up high between the bearing races through a zerk type nipple, 2 pushes of an impossibly expensive Swiss hand oil gun.
I would replace the collet if I could, but these W-20 collets are unavailable in the US from Schaublin, nor anyone else. I may have to import one from them in Switzerland if I hit the lottery.
 
I think we have obtained much help from all of the issues in the discussion already, I know I have.
Mosey

Offline Allen Smithee

  • Full Member
  • ****
  • Posts: 871
  • Mordor, Middle Earth
Re: Mill Creep
« Reply #24 on: January 05, 2015, 02:46:12 PM »
A quick internet search showed this to be an endless topic  ::) . The attached document is from the Central Washington University and seems to make sense to me as a novice.

What's bizare in that document is the way the section of 2-flute mills has the picture of a 4-flute one and vice versa!

AS
Quidquid latine dictum sit altum sonatur

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6355
  • Surrey, UK
Re: Mill Creep
« Reply #25 on: January 05, 2015, 03:30:04 PM »
Jason
Please go into the factors (or physics/geometry) that cause the end mill with more than two flutes to cut over nominal size. It's part of my "apprenticeship." I'm genuinely curious.
Thanks

The second page on Roger's link covers the reason.

J

Offline sshire

  • Full Member
  • *****
  • Posts: 3043
    • LS Editions
Re: Mill Creep
« Reply #26 on: January 05, 2015, 05:32:42 PM »
Thanks Jason. I missed that link and it is an excellent explanation.
Jo.
You quote Tubalcain, but isn't he on the same page as you re: slot cutters vs end mills. My understanding of his quote is that end mills are not center-cutting while slot cutters are.

I'm calling a truce on this one. When someone over here says "end mill" it's quite likely that they mean the same thing as slot cutter.
I'm sure you have no problem putting a suitcase in your boot. Over here it's a struggle to fit one's foot in.
Best,
Stan

Online Dan Rowe

  • Full Member
  • ****
  • Posts: 736
  • Dripping Springs TX USA
Re: Mill Creep
« Reply #27 on: January 05, 2015, 05:38:41 PM »
Stan,
The KEY word is slot DRILL. It has to be a center cutting end mill to be a slot drill.

Dan
ShaylocoDan

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6355
  • Surrey, UK
Re: Mill Creep
« Reply #28 on: January 05, 2015, 05:52:38 PM »
Stan,
The KEY word is slot DRILL. It has to be a center cutting end mill to be a slot drill.

Dan

Not so over here, to be a slot drill it has to have two flutes as well. Take a look at the picture below , both are centre cutting but we would only class the two fluted one on the left as a slot drill as generally a two flute cutter will give a more accurate slot width in a single pass. You really only need it to be ctr cutting if the slot does not extend to one end of the work.

Take the shaft below, both were cut with a slot drill to get an accurate width but the centre cutting facility is only needed for the longer slot where the tool need sto be plunged if you have not predrilled wither end.

But all this is of littel relevance now as cutter technology has advanced so much you can get 4, 5 or 6 flute cutters that will give an accurate slot and they can be plunged or ramped.

Quote
quite likely that they mean the same thing as slot cutter

Stan I think you meant slot drill, a slot cutter is another kettle of fish entirely :-[
« Last Edit: January 05, 2015, 05:56:01 PM by Jasonb »

Offline Allen Smithee

  • Full Member
  • ****
  • Posts: 871
  • Mordor, Middle Earth
Re: Mill Creep
« Reply #29 on: January 05, 2015, 06:11:35 PM »
Stan I think you meant slot drill, a slot cutter is another kettle of fish entirely :-[

Shirley you mean a woodruff cutter?

AS
Quidquid latine dictum sit altum sonatur