PM833T Spindle and Z-Axis Slop

J

Jason812

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I'm at my wit's end trying to be able to use a single point boring bar on my PM833T. I bet I don't have 10 hours on the machine if that. The entire head moves around when trying to use a boring bar. I've adjusted the gibs enough to almost cause the bottom screw to fall out without any change in drag on moving the head up and down. It did take some of the movement out of the head but nothing close enough to being correct. I pulled the gib and there aren't any burrs. Tried running the locking screws slightly snug and it doesn't work either. The head is moving on the column as if the dovetail is too loose.



The quill has so much slop it's barely usable to drill let alone try to use a boring bar.
 
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My guess is the gib is in backwards or is the wrong one for the machine or is seriously bent. You should be able to drive the gib down hard with the adjustment screw, and lock the head from any kind of movement. If you can't do that, then something is amiss with the gib fitment into the dovetail. It also looks like you have some kind of issue with the quill lock (last video).
 
davidpbest said:
My guess is the gib is in backwards or is the wrong one for the machine or is seriously bent. You should be able to drive the gib down hard with the adjustment screw, and lock the head from any kind of movement. If you can't do that, then something is amiss with the gib fitment into the dovetail. It also looks like you have some kind of issue with the quill lock (last video).
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It will lock the z-axis with the gib half way out of the casting. I'll flip it around this evening and see what happens. Also, I'll check it for straightness.

The quill was locked in the video's showing the head movement but not locked showing the play in the quill. Maybe once the z-axis is figured out, the quill issue won't be so bad.
 
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Are you trying to machine without the quill locked? If so, that would be an issue. I lock my quill and use the Z-axis to adjust depth.
 
No. The quill is only unlocked if I drill. The entire spindle head wobbles like its going to fly apart.

Guys at PM wanted me to pull the gib and measure. I'll do that when I get home and we'll see what they say.
 
I’m sticking with my prior post. The gib does not fit the dovetail or is bent or installed wrong. I suppose it could be a wrongly machined dovetail in the casting or some other protrusion in the dovetail, but the gib is the first place to look.
 
I can slide a .002" feeler gauge under the middle third on the side facing the column when setting the gib on the way of my PM1340GT. Flip it over and there is a rock. Hold one side down and a .009" feeler gauge fits under the other end.

I mic'd the thickness and sent that info to PM. Not sure what it's suppose to be

We'll see what tech support says tomorrow.
 
Using a feeler gage is not very helpful. Watch this video. That’s proper technique. Another example. Hope this helps. Is this a new machine?
 
I was checking the gib for flatness out of the machine and you were right, it's not perfectly flat. Using the indicators is good info to have once I get it back together.

Machine is about a year old and unfortunately, it doesn't have hardly any hours on it. This was the first time I've tried to bore with it.
 
Sounds like a defect in the gib IMO. PM should be able to make it right with you. My grizzly has garbage gibs and you can't do much until you get it corrected.
 
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