Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure I
had a sharp end mill. I really need some new ideas.

thanks

Kelly Jones wrote:
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure I
had a sharp end mill. I really need some new ideas.
Does this machine have an R-8 taper? Get end mill
holders, they have big set screws that engage the
Weldon flat on the end mills and prevent spinning
and walking out of the cutter. That vibration may
have been some looseness in your setup/fixture.
Each time it vibrated, it overloaded the collet's
grip on the cutter, and the helix angle of the
side flutes allowed the tool to be pulled out just
a little.

Jon

On 2008-10-15, Kelly Jones wrote:
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure I
had a sharp end mill. I really need some new ideas.

This is why endmill holders are made in sizes which fit collet
spindles. You want that -- either one with setscrews to grip by the
Weldon flats for US mills, or a special Clarkson collet chuck if you are
in the UK where you can get the threaded shank Clarkson type endmills.

Both of those resist the walking of the endmill out of the
collet on heavy cuts. (And I suspect that you were making fairly heavy
cuts -- or had a cheap or worn collet, but *never* trust a collet for
heavy cuts on larger endmills.

Oh yes -- also put sacrificial spacers between the workpiece and
the table to prevent those divots. :-)

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
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Kelly Jones wrote:
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure I
had a sharp end mill. I really need some new ideas.

thanks




How secure was the piece you were working on?

Was there a large span between supports that might allow for harmonic vibrations to be set up?

Are you sure you had the right collet and that it hadn't been worn/wallowed from the
inside previously?

Just a few things to think on.

Al

Kelly Jones wrote:
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure I
had a sharp end mill. I really need some new ideas.

As others have suggested, go to endmill holders.
If you can't, degrease the collet bore and endmill
shank before installation. Look at using roughing
cutters if you are roughing.

"Jim Stewart" wrote in message
.. .
Kelly Jones wrote:
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made
sure I had a sharp end mill. I really need some new ideas.

As others have suggested, go to endmill holders.
If you can't, degrease the collet bore and endmill
shank before installation. Look at using roughing
cutters if you are roughing.


I was getting severe vibration on my gizzly mill, super x3, z axis.

The filmsy gibs screw was broke. Thing would just rotate, not tighten
anything up.

Replaced it with a larger bolt, lot better now.

xman

I haven't posted in a very long time, but an older gentleman gave me some
very good advice on 1/2" cutters pulling out. All you have to do is clean
the shank as best you can, then dip the cutter into chalk line chalk to coat
the shank. The chalk absorbs any oil or reside, & is apparently abrasive
enough to help grip the cutter to keep it from pulling out. Hope this helps!
Brian

"Kelly Jones" wrote in message
. ..
Got a problem with my 9 x 42 horizontal - vertical mill (Grizzly).

Actually, probably more a problem with me.

Twice now the end mill has walked out of the collet and made unpleasant
looking marks on the table. Both times when making the cut the whole
machine has vibrated (not badly, but noticably). I have examined the
assembly for looseness, ensured the bolt is tight, and free of burrs and
chips, reduced the feed rate to a crawl, changed the speeds, and made sure
I had a sharp end mill. I really need some new ideas.

thanks