Quick Turn 8N x axis carriage alignment?

nate3d · Dec 28, 2017

Hello everyone,

I have just acquired a 89 QT8. I see the carriage is out of alignment in the X axis. The turret is aligned with the spindle bore fine, but I can get .002" out if I sweep the face of the turret in a 2" span. That seems like a lot to me? It's out as if you crashed a drill into a part really hard and it twisted the carriage back. Now a drill will not be perpendicular?

Has anyone done a realignment to the carriage, I assume that I would need to access the bolts attached to the trucks riding on the linear ways? Do I just remove the X way covers to gain access? I do not have live tooling which should be easier, correct?

Thanks,
Nate

benganboll · Dec 28, 2017

Do you have all the manuals for this machine?

gmc1724 · Dec 28, 2017

nate3d said:
Hello everyone,

I have just acquired a 89 QT8. I see the carriage is out of alignment in the X axis. The turret is aligned with the spindle bore fine, but I can get .002" out if I sweep the face of the turret in a 2" span. That seems like a lot to me? It's out as if you crashed a drill into a part really hard and it twisted the carriage back. Now a drill will not be perpendicular?

Has anyone done a realignment to the carriage, I assume that I would need to access the bolts attached to the trucks riding on the linear ways? Do I just remove the X way covers to gain access? I do not have live tooling which should be easier, correct?

Thanks,
Nate

How are you "sweeping" the 2" span? If you're doing it by holding a dti in the chuck then it may be the spindle is out of alignment (much more likely post crash).

nate3d · Dec 28, 2017

Hello,

Yes, I have the manuals, but did not think they cover this area for repair purposes. Wondered if someone has done the alignment before and knows what to expect.

I have the indicater in a magnet arm stuck to the front wall of the machine. I sweep the area where tools would sit against the back wall of the turret. I also checked the face where you would attach a boring bar holder. If so, the holder would be cocked back out of perpendicular to the Z axis. Both readings are about .002" in a 2" sweep.

Once dialed in, I was hoping to then check head alignment by turning a part and checking for taper.

Thanks

kevin66 · Dec 29, 2017

nate3d said:
Hello everyone,

I have just acquired a 89 QT8. I see the carriage is out of alignment in the X axis. The turret is aligned with the spindle bore fine, but I can get .002" out if I sweep the face of the turret in a 2" span. That seems like a lot to me? It's out as if you crashed a drill into a part really hard and it twisted the carriage back. Now a drill will not be perpendicular?

Has anyone done a realignment to the carriage, I assume that I would need to access the bolts attached to the trucks riding on the linear ways? Do I just remove the X way covers to gain access? I do not have live tooling which should be easier, correct?

Thanks,
Nate

If the lathe is under power I would just do a simple check by chucking up the largest dia stock the machine will hold that's at least an inch or more thick and take a test face cut. Then throw it on a surface plate and see if you get any taper from the outer most dia to the center. I would suggest aluminum to remove the problems with running out of surface speed at the center and giving a false reading on the indicator.

ewlsey · Dec 29, 2017

You just need to align the turret face to the X axis. The whole turret assembly is bolted to the top of the carriage. Sometimes they have a few taper pins as well. Loosen the bolts and tap the turret around to get it lined up.

Don't mess with the linear guide trucks!

nate3d · Dec 29, 2017

kevin66 said:
If the lathe is under power I would just do a simple check by chucking up the largest dia stock the machine will hold that's at least an inch or more thick and take a test face cut. Then throw it on a surface plate and see if you get any taper from the outer most dia to the center. I would suggest aluminum to remove the problems with running out of surface speed at the center and giving a false reading on the indicator.

I am not sure that would show the problem, unless the linear guides were also cocked at an angle? I think even having a facing tool crooked it would still face the part straight? Problems come in if using long drills and perhaps a partoff tool. I would think they would be the tools to show problems? Still, I am going to try your idea and see what happens. I appreciate your ideas.

Nate

nate3d · Dec 29, 2017

ewlsey said:
You just need to align the turret face to the X axis. The whole turret assembly is bolted to the top of the carriage. Sometimes they have a few taper pins as well. Loosen the bolts and tap the turret around to get it lined up.

Don't mess with the linear guide trucks!

OK, I will check in this. I had the turret off and cleaned everything up behind it. However I am not having a radial issue, it's the turret being off in the Y? Plane as if you were looking straight down at the machine. If what you say is correct, I would not even have to remove the way covers? There are bolts at the top of the carriage that help to re-adjust this... That would be great, I will take a look. Thank you for the response.

Nate

Pete Deal · Dec 29, 2017

I think what you are saying is that the tool is off in the Y axis so the turret is turned a little right? Assuming that is what you are saying you need to loosen the bolts that hold the turret to the front part of the curvic coupling. Also on mine there were two taper pins between the curvic coupling and the turret- these need to be removed. I left them out. Then the turret can be adjusted. In my case I had to completely remove the turret and the coupling from the turret because the coupling was very tight in there and I could not get it to move. Here is the post where I did mine, unfortunately that stupid photobucket messed up all the photos.
http://www.practicalmachinist.com/vb/mazak/mazak-qt15-turrent-removal-325807/

wippin' boy · Dec 29, 2017

first thing I do is set head taper
next I sweep a pocket
then I go looking for the stuff your talking about

wippin' boy · Dec 29, 2017

unless your tapping 6-32 in inconel
or reaming a hole to two tenths
that two thou ain't gonna bother much

nate3d · Dec 29, 2017

I think I am confusing everyone, haha. I'm sorry. I believe the turret is lined up well radially? I used a coax indicater in a boring bar pocket and its within .0005 so I think the cervic coupler is ok.

The turret is out as if the whole x axis carriage was twisted counter clockwise. I can imagine this happening if a tool was crashed into the spindle/stock hard enough in a Z- direction. That's why I assume I would need to loosen something near the trucks? Unless there is another kind of adjustment.

Turret straight like a level clock on the wall... Check..

Its more like the clock is not sitting flat against the wall... Like there is a bump pushing the clock out behind the 9:00 position??

The turret cannot be adjusted in the carriage this way, can it? Only radially like hands moving around a clock?

nate3d · Dec 29, 2017

So if I set a 3" long drill and set the tip at centerline, wont it rub like crazy at its base when I drill in 3" in? I guess it would only rub 2 to 3 thou. Perhaps its not that bad. If fixing it is a pain in the butt, I will just live with it.

wippin' boy · Dec 30, 2017

I am positive I would see how it does before I go after those rail trucks

wippin' boy · Dec 30, 2017

if you had a critical need a 2 thou shim fixes that drill pocket that day

ewlsey · Dec 30, 2017

nate3d said:
Its more like the clock is not sitting flat against the wall... Like there is a bump pushing the clock out behind the 9:00 position??

The turret cannot be adjusted in the carriage this way, can it? Only radially like hands moving around a clock?

Typically, the turret can be adjusted this way.

Think of the X axis as the cross slide of an engine lathe. The entire rotating turret assembly bolts to the top of the X axis just lie a big tool post bolted to the top of a cross slide. You should be able to loosen those bolts and move it. It may have adjuster screws or taper pins, but it should be possible to move it.

wippin' boy · Dec 30, 2017

some yes
some no
I don't recall on a qt8. that's a pretty small turret body
I'm pretty sure there is no "adjuster screws"

Pete Deal · Dec 30, 2017

How did you check this? with an indicator on the front of the turret as you stroked X? I don't think sweeping a boring bar socket is very good either. On my machine, a QT15, the tool holders have bands in them with coolant holes and all kinds of interruptions. I bought about a foot long piece of ground stock like they use for linear bearings from mcmaster to use as a check bar.

wippin' boy · Dec 30, 2017

I think he is checking it properly.
a test bar just adds the variability of the pocket fitup

nate3d · Jan 3, 2018

Thank you everyone. I have decided to just shim for now. It did make it closer. Hopefully someday ill have time to open up the carriage and make the correct alignment.

Thanks, Nate

Quick Turn 8N x axis carriage alignment?

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