Model 53 Bad Wobbly cuts

[Zach Nagle]

Hi Everyone
I'm pretty much self taught, our machine is not in production, more of a custom environment. So if this question is stupid, please forgive...

Last week I could not get my tool holder out. I took off the front cover and dusted off the thing, gave it a good cleaning, and the tool holder eventually popped out. Well, when I went to cut my piece, the lines are horrible. Please see the picture. I believe this wobbly cut (and my difficulty getting the tool holder out) has something to do with the bearings that hold the tool holder being "off", rather than my tools being dirty and messing up the calibration.

Thoughts?

thanks. Zach

[Forrest Chapman]

Zach, check to see that the tool holder is being pull all the way up in the cone. I have had the gripers grab the very end of the retention knob before and the tool holder did not seat tightly in the cone. I cannot see bearings being that bad without a serious vibration and noise.

Forrest

[Rob Davis]

Zach, did you figure this out? If the bearings were this bad the vibration and noise would be deafening. Is the material wood you are cutting? And are you using a real small cutter where you might get tool deflection or material hardness variations? If you think about bearings and tooling turning 15000 rpm it would make chatter with very short "wobbles" and yours look long. Is your rpm fast enough?
Just curious to learn from your situation.
Rob

[Daniel Vonderheide]

Zach,

Check your lash on both the x and y axis with a dial indicator and a magnetic base. The waves look like an axis is loose or that the material was not held down very well.

[Zach Nagle]

Dan/Rob thanks for the words, I appreciate it alot!
As I said, I am pretty much self taught and have no idea what my x and y axis lash is. I'm really excited to meet a Thermwood tech in person, lol.
However, I am cutting 3mm sintra PVC with an 1/8" compression bit, and have done this 50 times with no problems. The filters in our air pumps are brand new, and while our plenum is cracked(..yeah,silicone..) and our table somewhat old, the suction holds the material well. I observed no material movement.

[Zach Nagle]

oh, and my RPM is 18000.

[Zach Nagle]

Adam visited our shop to diagnose the problem....
1)The x and y leash were both within .005, so that is fine.
2)Apparently we need a new screw, the middle of it is worn down.
3)The ball nut was replaced. It was caked with dirt and grease because one of the wipers was missing.

I have a feeling the dirt and grease that got into the ball nut degraded our screw. Anyway, thanks everybody for looking at my post. -Z

[Rob Davis]

Thanks for posting the resolution. Too often the issue gets solved but the answer isn't posted. Glad you got it figured out. Don't feel bad as I don't know what the x/y lash or leash is either!