Loose tailstock on older QT10, need help

Hi Guys,

The tailstock on my old QT10 is very loose when unclamped. You can probably see the top of the tailstock move 1/4 of an inch or more while its unclamped and moving. Its bad enough that its creating a gap between the ways and possibly lettings chips in between, so I need to get this fixed.

I took the cover off today and it looks like I have an air/hydraulic booster and a hydraulic cylinder to clamp. See attached pics. Looks like theres a nut that I can tighten to adjust all this, its split on one side and has a cap screw to lock it. Im guessing this has worked loose.

So hoping you guys can confirm im on the right track with this and how much to adjust it. Would there happen to be a procedure of maybe tightening all the way and back off X number of degrees or turns or do I just tighten it up till it seems right?

How do get the machine in an unclamped state to adjust it? I cut the air to machine but I guess solenoid must be still closed as its still clamped. Can I move tailstock manually and hit e-stop while moving maybe to leave it unclamped? Thanks.

Mark

mmurray70 said:

How do get the machine in an unclamped state to adjust it?

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In the back electrical panel on the left door there are several toggle switches. Flip the switch marked tailstock to unclamp then adjust the nut.

Philabuster said:

In the back electrical panel on the left door there are several toggle switches. Flip the switch marked tailstock to unclamp then adjust the nut.

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Any suggestion on how tight is tight? Should i still be able to rock the tailstock a little or not? If so how much?

Just a follow up, my machine (early 80s QT10 with T1 control) does not have a switch in the electrical cabinet to unclamp tailstock. After some searching online I actually found the mazak procedure for adjusting this and you have to press two buttons (one brass and one plastic) on the solenoid valve (located on air/hyd booster) to unclamp it. Removing air pressure, air line or pushing e-stop while moving or anything else doesnt seem to unclamp it.

They specify in the manual to turn the nut fully clockwise and then back off 50 degrees which sets the piston travel to 0.5mm. I did this and still found it a little loose and decided to set it tighter to avoid getting chips in ways. Im only about about 10-15 degrees out from seated now and there is very little play and no binding or strain on the motor. Seems perfect to me now. Previously the nut was almost a full turn too loose.