Has anyone noticed chatter when using the A2Z end mill holders on thier mills?

I was facing a block of 6061, making cuts of 2.5 mil using a 3/8 roughing end mil, at the lowest spindle speed. The chatter was slight but it left noticeable marks on the material. I changed to the 3/8 ER16 collet and the problem did not re-occur. The cuts were much cleaner as well.

Rick

Sounds like you have a little run out maybe, Rick. The pictures I've seen for the end mill holders look like they are about 1.5" long, so you're just hanging that much more out in the breeze.

Is there some problem using the ER16 collets directly in the spindle. It's hard to find a more rigid setup than actually having the end mill right up inside the spindle nose.

Still, a DOC of just .0025" for a 3/8 end mill doesn't seem like it should chatter, even in the extended length of the holder.

Dean W
http://tinyurl.com/DeansProjects

The A2Z holders use a set screw to lock the bit in place. Does you bit have a flat on one side for this purpose? There are a couple of problems I could think about with the A2Z style holder.

1) The holder or bit shanks is not perfectly clean, a bit of dirt could cause the bit to 'tip' as you tighten the set screw.

2) The bit shank is not properly sized causing it to be pushed off center by the set screw.

3) Using a really long bit in combination with the holder would increase vibration and chatter for the reasons Dean mentioned.

Dean and Jeff,

The end mills that I use have the flat and I take extra care to insure that the set screw is in the flat and is tight. I always check to see if there is debris in the channel since I stuck one of the end mills in the holder. That was fun!!!

This may not mean much, but the sound that the end mills make is much quieter with the ER16 collets than with the holders. I want to check the other size holders and the other 3/8 two flute roughing cutters to see if they behave the same way.

Again, it is not critical, I am wondering if it is something that I am doing wrong.

Rick

It could just be the combination of the style of cutter and the extra length. The greater the distance from the tip of the bit to the spindle the more 'leverage'.