Quick Turn 15 Tailstock body slips. Help!

Midnight Machinist · Jul 19, 2014

Hi Everyone,

I'm finally getting around to using the tailstock on the qt 15 and the tailstock body gets pushed back when I engage the quill against the work. This happens even with the tailstock quill pressure adjusted SUPER low. How do I fix this?

Also, there's a switch inside the electrical cabinet door next to the chuck ID OD clamp switch that says tailstock " clamp" and "unclamp". Right now it's in "clamp". How shall that switch be positioned and for what???

Thanks very much guys,

Grant

yardbird · Jul 19, 2014

I had this happen on a Cincinnati Avenger from time to time. I had to take to cover of the side and tighten up a couple of bolts that came loose occasionally. My guess would be that the clamp is out of stroke. At least that was my situation.

Brent

yardbird · Jul 19, 2014

I tightened the bolts while the tailstock was in the clamped position. You want to be sure when its unclamped it is moving freely. Do you have clamp/unclamp switch on the control panel or Is it automatic? Some do some dont. The Avenger didn't. Does it sound like it the clamp/unclamp working?

Brent

yardbird · Jul 19, 2014

Sorry I didn't notice that this thread was in the Mazak forum when I posted. sometimes im bad about that.

Brent

Richard King · Jul 19, 2014

As long as you have some guards off check to be sure some chips haven't worked under the TS. Lock it up and see if you can slide in a .001 or .002" feeler gage in anywhere. Rich

machtool · Jul 19, 2014

That's a hydraulic clamped tailstock. Coils are prone to burning out. I'd be looking there first. If you toggle that clamp / unclamp switch, you should be able to see or feel the lines twitch as the pressure changes sides. You might also notice a slight dip on the pressure gage. You might need a second set of hands to work the switch while you have a look.

Regards Phil.

(On Edit). You can swap a coil from the tailstock advance / retract solenoid for testing.

wippin' boy · Jul 20, 2014

There are bolts going through the clamp cylinders into the clamping plates( look kinda like t-nuts) .bolts are Under front cover of tailbody. The bitch part is the locking screws are in a shitty spot through the side under chain cover. Tighten them with power off so tailbody can just move under power.

zak300sy · Jul 20, 2014

Piggyback on whipping boy's reply. We've had several with a T+ control. It sounds from your description that you've got a T32 control, but i'm pretty sure the iron is the same on these ones. There is a DOUBLE SET SCREW + a brass keeper on the two T+ vintage machines i've torn into. Down under the ways on the clamp plates. You'll have to access one from the front and remove sheet metal off the back end to access the other. Make sure everything is super clean under there. Take the cover off the side of the tailstock, you'll see a couple of shafts with a hex on the end. Do it with the power off so you're not fighting the hydraulic on the clamp mechanism. The other problem we had with one is that the underside of the ways is so worn & beat up in one spot, it will still slip. Only run one part on that machine, so we made up some special tool holders to do the end work that will clear the tail stock. Also save a boatload of time by not moving tail body back and forth ever part, only the quill moves. It was a parameter change on the T+. I think the switch you referred to in post #1 will do what I just described on the earlier controls.

wippin' boy · Jul 20, 2014

Missed switch question.
Should be in clamped position
Unclamp is for service works discussed
I forgot the switch was there. I just turn control off to make adjustments.

Midnight Machinist · Jul 23, 2014

Thanks guys!!

I think it's mechanical, the hoses are definitely jumping when the solenoid moves it's spool.

I'll have to dig for the locking screws, but then it looks pretty straight forward. I'm so glad I asked, I knew it could not be as easy as simply tightening the big obvious bolts under the ts cover.

Thank you again all,

Grant

wippin' boy · Jul 23, 2014

I knew it could not be as easy as simply tightening the big obvious bolts under the ts cover.

well...

it is mostly

we just like hearing ourselves type

Midnight Machinist · Jul 25, 2014

"mostly" is the key word here! I'd have buggered the set screws likely without y'all's help.

Thank you all!

Cheers,

Grant

wippin' boy · Jul 25, 2014

next!!!!!!!!!!!!!!

he hollered from behind the counter in a in his best soup Nazi outfit

machtool · Jul 25, 2014

wippin' boy said:
next!!!!!!!!!!!!!!

he hollered from behind the counter in a in his best soup Nazi outfit

I just got a private message, there's a spindle rebuild coming up. A juicy one with a hydraulic lock nut.

Phil.

Cole2534 · Nov 29, 2021

Does anyone have pics of this? I feel I'm about to need to tighten my clamping mechanism.

Midnight Machinist · Nov 29, 2021

I'm sorry, I don't have that machine and can't remember what was happening way back then. Good luck though!

Cole2534 · Nov 30, 2021

Got it! Now the tailstock will actually build pressure on the gauge instead of just moving the body back.

First you remove the way covers, front and rear to expose the 2 pairs of set screws. They're hidden by grease and grime in these pics, but they most certainly must be loosened. I just backed them off a turn or two.

Now remove the tailbody's cover to expose the clamp screws.

With the control off, I tightened them about 1/2 half turn each. This reduced my running gap between the shoe and the way from well over 1/8" to maybe a 1/16"? I didn't gage it.

Turn on the control to run some test cycles and if you're content turn the control off then reassemble.

It's dead simple, just gotta get to those set screws. The first thing I noticed is that the body moves and stops much more smoothly.

maint@buntingmagnetics · Nov 8, 2023

I'm glad I founf this thread. I have a QT-15 that when the operator uses the tail stock the quil bumps the stock back when the T plate is adjusted to .03125-.0625" any tighter and the tail stock wont move. It also seems that when the operator runs the programe that the tailstock gets shoved back in one motion instead of the .0625" bump that happens when done manualy.
Would this be the coil going out or do I need to replace the T plates. The rails don't seem to be overly worn and the fluids are topped off.

Thank you for your time and the OG post.
Chris

PS: The rear through bolt seems to be bound up. I was able to loosen it and adjust the plate once now it does a half turn eather way anf stops. I'm hesatent to go ham on the bolt.

noname777 · Nov 10, 2023

most of the time it is just rails not lubricated properly. and this stupid PIN would always disengage itself, not to drag a tail. Hydraulic pressure is weak.

Quick Turn 15 Tailstock body slips. Help!

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