Number of bellevilles for PDB?

[cobrakai]

I recently had a TTS holder pull out which is very rare for me. I have always followed the clean/lube practices and been able to mill to the machine's power limits and even in chatter situations without pulling out. But this happened with a relatively light load so I am trying to figure out why. My mill had been sitting for about 3 months and last time I used it, it was running great.

I have an 1100 Series II and my instruction manual has 6 bellevilles stacked ()()(). I am looking at the newest instructions and it looks like they went to 8 washers. Why would that be and what do you guys recommend I go with?

My compressor fluctuates from 100-120PSI before it starts up again, so I always set tension so it will just barely release at 100psi.

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[popspipes]

I had the same problem with a .25 endmill a week ago, I installed a new cutter and there was instant chatter, cutter pulled down, luckily I caught it before it broke the cutter, the problem was that I had an aluminum chip on the face of the holder that kept it from seating on the spindle nose. My R8 collet only contacts the tool on the bottom 1/8" and the spindle face so if one of the contact points are not seated correctly I get chatter.

edit: I have a 2 stage compressor set at 150# and when I get chatter it will pull out the tool.

[popspipes]

I recently had a TTS holder pull out which is very rare for me. I have always followed the clean/lube practices and been able to mill to the machine's power limits and even in chatter situations without pulling out. But this happened with a relatively light load so I am trying to figure out why. My mill had been sitting for about 3 months and last time I used it, it was running great.

I have an 1100 Series II and my instruction manual has 6 bellevilles stacked ()()(). I am looking at the newest instructions and it looks like they went to 8 washers. Why would that be and what do you guys recommend I go with?

My compressor fluctuates from 100-120PSI before it starts up again, so I always set tension so it will just barely release at 100psi.

They use a stack of 8 pairs now, it has the same pressure on the collet but the belleville washer flex is less.

[cobrakai]

I contacted Tormach and they said they switched to 8 to get a little more static compression (higher force) and still have the required deflection to release the tool.

I am starting to think the root cause of my issue however is a poorly maintained R8 taper. I will try lubricating it and seeing how it goes.