Subject: End Mill life

From: [email-masked] (Bob MacDonald)
Date: Sun, 15 Dec 1996 23:28:50 GMT

This may be a question without an answer, but I'll ask it anyway. How
much metal can I expect to cut away with an end mill?
	I was building the ajustable tool post featured in the October issue
of PIM. Buy the time I finished my third tool holder the 5/8" (HSS 4
flute made by YG) end mill I was using  was dull. I had set my RPM
according to data published in the back of the Cleveland END MILL
catalogue. Depth of cut was .010", feed rate was very slow. The
materal I was cutting was HRS, 1.5" wide to a depth of .370". The
width of the slot was 1.00" wide.
	Thanks
		Bob

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From: [email-masked] (Fitch R. Williams)
Date: Mon, 16 Dec 1996 06:02:30 GMT

>width of the slot was 1.00" wide.

Last weekend (12-7-96) I removed about 2.4 cubic inches of
metal using a 5/8" HSS end mill making a tool holder - about
the equivelent of 4.3 of your .555 cubic inch slots
(assuming I understand correctly and they were .370" DX 1.5"
L X 1"W).  I was taking a cut two tenths of an inch deep
across the width of the mill at 660 rpm (~109 sf/m),  didn't
measure my feed in ipm but it was fairely agressive, lavish
flood of dark cutting oil for coolent to wash the chips
away.  I had a river of swarf running off the vise.  

I finished by taking a .010" cut along each side of the
slots to finsh them up nice and smooth.  This is not the
only time I've used this mill.  Its nothing fancy, just
plain HSS.  

The cutter did not get noticably duller during the process.
I just went down to look at it to be sure.  I will be using
it again next weekend.

I have experienced much better cutter life and surface
finishes since I  started to use flood coolent - and lots of
it.  I think you will get a lot of input from the group
about using drip or mist coolent.  They are probably
correct, but I already have the other stuff.  It is messy
though.  And it makes cleaning the mill up messy also.  But
I have time, $$$ for cutters is harder to get my hands on.

I ended up using a RTV calking gun to build up the sides of
the coolent troughs around my vise so that the oil wouldn't
run over the sides.  I also have a roll of aluminum foil and
some magnets so that I can set up shields to direct it back
onto the table and into the "T" slots.  I'm getting better
at containing it the more I use it.  

I have gotten many good suggestions on replacements for the
oil, but they all require adding water.  I hate to add the
water.  Its probably just me.  I'm trying to get my mind
around running stuff with water in it over my lathe ways but
not succeeding very well.  The lathe and mill have to share
a coolent system.

Fitch

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From: [email-masked]
Date: 16 Dec 1996 17:17:08 GMT

In article <[email-masked]>, [email-masked] (Fitch R.

>not succeeding very well.  The lathe and mill have to share

I have two coolmist magnetic units with the coolant from Wholesale Tool,
It was used on 2- 10 in dia insert type cutters cutting in a straddle
setup and each milling a 3/4 X 3/4 notch on cold rolled steel.  I was
making large Tee nuts.  The mister worked better than flood, and dkd not
rust the waaaaays.

Cecil in oK