This might just apply to me but I though I might mention it as I was on the verge of tearing all my hair out, I cut 316 stainless quite frequently and use a tipped tool holder that has a 12mm shank, the largest I can fit in the toolpost. I was plagued with tool chatter (squealing) to the point of very bad chatter (leaving large spiral lines on the billet) with horrendous noise.
I spent weeks trying to reduce the problem which ended up as months with no result. I changed speeds and feeds, tool height, I tightened up the head bearings to a point that I lost alot of top speed on my VFD controlled spindle.
To cut a long stort short, An idea came to me to place a bit of bar longways under the tool holder right under the cutting end and wedged the other end on the saddle.
Immediatly all the squealing stopped and the tool cut properly. So experiment over and the problem seems to be that the actual tool holder was flexing.
I found an old file that was thin enough for a packing piece and cut it to fit under the tool holder to support the whole tool holder length and voila, problem solved.
The moral of this is avoid buying cheap no-name tool holders on Ebay.
Cheers.  |