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Milling Machine vibration

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

Reply to
Kelly Jones
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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

Reply to
Jon Elson

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.

Reply to
DoN. Nichols

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

Reply to
Al Patrick

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.

Reply to
Jim Stewart

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

Reply to
robert

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

Reply to
GR81

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