CNC lathe turret cant be aligned ATTN MIKE COPE

tntcustom · Dec 24, 2020

OK, Have a 18" chuck lathe that we bought new in about 2016-2017 IIRC. It has always cut well, with no alignment issues. Although we have never physically checked turret slot alingment, we check drills and boring bar holders regularly and they have always been within about .001 or so.

We had a tool break and move the turret out of square, so we squared it and checked the boring bar, good, so we ran again.

Then it seemed inconsistent on size, which has never been an issue. We removed the whole turret back to the curvic, and found chips inside(swarf). cleaned and the tech put it back together and he trammed the stick tool slot and left.

We setup a centerdrill and it was of in "y" (a 2 axis lathe so there is no y axis) almost .120"
We trammed the boring bar holder same thing, checked the tool slot its 0.000"

HAd the tech come back, and he re pulled the turret, rechecked all the tapered pins, and put all the pins back in, and the boring bar pocket is perfect 0.000, but the tool slot is out .025", he pulled the pins, and aligned the slot, back to .120 out on the CD. put pins back and its 0.000

Now, has anyone ever had a turret where the 2 dont agree? the tech, dealer service manager, and Machine Tool Dynamics people all agree it shouldnt be possible, unless the MTB didnt shim the turret correctly from the factory.

As a note, the headstock is aligned with z within .001" over 16" on a 4" daimeter bar, and the tailstock and headstock are also within .001 on the same bar.

litlerob1 · Dec 24, 2020

I feel like you are shying away from telling us what machine this actually is......If it's some Chinese thingy than I cannot help.

Year, Make and Model please....

The Herth can have error too. It sounds like it needs a whole or dead shift on the Herth, not just rotation.

But I never put the taper pins back in, amateur bullshit there. Taper pins are for reference only. Get the Turret close, remove the pins, dial it in, tighten it down, go home.

All that is assuming FIRST that the Turret is Perpendicular to the Chuck's center of rotation and the Chuck face is Perpendicular to the Center of rotation. And if Geezer is using a Coax, that the jaws are bored correctly and whatever is holding the Indicator is straight. There is a lot that goes into re-aligning a Turret.

But IMHO, it sounds like you're working on junk, and your Applications tech is mildly retarded.

R

Vancbiker · Dec 24, 2020

More info please. What is your setup for sweeping the id holder? I've seen folks slap a mag base to the chuck face and think they had an alignment issue when in reality, most of what they were seeing was droop in the indicator setup.

Should describe the nature of the "We had a tool break" event. What kind of tool and how did it occur. Breaking a tool during "normal" cutting is very rarely enough to knock a turret out on good machinery. Breaking a tool by crashing it into the chuck is an entirely different matter.

Hardplates · Dec 24, 2020

Something makes me feel this machine was crashed pretty hard but nobody wants to own up to it.

Something else also tells me that on this machine the turret and spindle are not on parallel planes. IE a slant bed machine with a spindle mounted on a horizontal plane. Getting everything lined up on such machines can be a PITA to say the least. Just because the spindle is parallel to the Z axis does not mean the spindle plane intersects the x axis plane at the correct location.

tntcustom · Dec 30, 2020

No secrets. It was Crashed. Not super hard though. Picture a part shaped like a top hat, 16” large OD, 7” ID 6” tall. Chucked with bottom of hat towards tailstock. Accidentally misread depth of bore, and bored the “top” out of the hat. 7” dia by .5” thick ring got wedged between the part and a 2” boring bar. Took out the insert and seat, and pocket. But bar was rebuildable. Did not pull part out of chuck or stall machine. Machine threw a z axis overload.

Not a secret, but trying to give machine builder a chance to work with us. It’s a Taiwanese built US branded machine.
We build custom machinery, and have no issues aligning stuff. We always pull the pins, it was just a test to put them back in and SEE where it came to, assuming it had pins aligned from factory.
The headstock is a unit spindle in a cast housing. It bolts to the slant bed casting on a machined surface parallel to the x axis. Headstock has a pivot pin under the casting.
Between the turret and the x axis there’s a shim plate that is ground to thickness at machine assembly to shim turret up to proper center height. Our feeling is this plate is incorrectly sized, and machine left factory with boring bar holder on CL, and slots out.

We swung in pockets with a Blake Coax, a mititoyo tenths on a nova hydraulic holder, and an interapid on a super stubby starret mechanical arm. All agree within .001” . Close enough for pushing the 3/4” centerdrills and 3.5” quad drills we use regularly.

Bobw · Dec 30, 2020

As a note, the headstock is aligned with z within .001" over 16" on a 4" daimeter bar, and the tailstock and headstock are also within .001 on the same bar.

IS.. post crash.. Or WAS pre-crash?

Did you knock the turret out of square with the Z axis? Slipped on the trucks or something?

Those are my only 2 thoughts, though I would be indicating every thing that could possibly
be indicated. And some point just say F'it, and shim and/or machine the stick tools to get
them on center.

tntcustom · Dec 30, 2020

IS post realignment.
After crash, headstock was out of square with Z, we realigned that by indicating in chuck face 0, then cutting a test bar chucked on 1 end. w/in .0005/14” on a 5” diameter bar.
Rechecked tailstock by putting tailstock into bar and recutting again, w/in .0005/14”

Squared turret to z axis by indicating face and edge of turret 0.0002/8”
Then realigned turret using boring bar holder.

We pulled the waycovers and checked truck bolts, (we thought that might be an issue as the tech had seen a crash before shear some of them). They are all tight, without play.

Machine has no repeatability issues, post crash we ran 40 parts 16” long +- 0.0005 on diameter without making diameter offsets at all over 2 days. In 4140 at 36 HRc

Gut says it’s the shim plate, and it needs reshimmed.
Problem with saying Fit and running is that this is a machine purchased brand new from a builder who now tells us the model is being discontinued, and I have a feeling it’s over quality issues, as I have another one that required a spindle rebuild after 3500 hrs, because the bearing retainer bolts for the front bearing backed out because they were never loctited in the first place.

wmpy · Dec 30, 2020

In the first post, you mentioned repeatability issues, but now since getting the chips out of the curvic coupling, the machine repeats well again?

What is the construction of the machine. Assuming slant bed- true slant bed or "flying wedge" design?

You say you squared the turret to the Z axis. Did you check if the turret is parallel to the Z axis in the "Y" direction?

Did you ever have problems with your turning tools cutting to center before the crash? Or do you only make parts with holes in them?

tntcustom · Dec 31, 2020

Repeats fine again. Held .001 over 2 days. Post realignment.

True slant bed.

Not sure what you mean by squaring the Y, it’s only a 2 axis machine. If the turret is out of square in Y then what would the issue be? Something would have to be manufactured incorrectly right? Solution would be to taper the shim? I’ve never heard anyone checking Y on a 2 axis lathe. I’d like to know how if that’s what you mean.

Re: turning to center, we have discussed this with service people a lot. We had no issues turning to center, BUT... when looking at our standard stick tools, they almost all stick out from the turret approximately to the center of the boring bar holders, which puts them back on center. So we should be ok.

wmpy · Jan 1, 2021

tntcustom said:
Not sure what you mean by squaring the Y, it’s only a 2 axis machine. If the turret is out of square in Y then what would the issue be? Something would have to be manufactured incorrectly right? Solution would be to taper the shim? I’ve never heard anyone checking Y on a 2 axis lathe. I’d like to know how if that’s what you mean.

You understand me correctly. But with a slant bed, you're right; the only way for it to be out in the Y would for something to be made incorrectly... or some wicked twist in the casting. Not likely at all but worth the small effort to check.

I can think of no other reason for the issues you're having other than what you already stated about the shim being ground wrong. I guess it's up to you if you want it fixed if all your tools are pretty much cutting at the same X position. It might not be worth the effort. Good luck.

Ox · Jan 2, 2021

tntcustom said:
Repeats fine again. Held .001 over 2 days. Post realignment.

True slant bed.

Not sure what you mean by squaring the Y, it’s only a 2 axis machine. If the turret is out of square in Y then what would the issue be? Something would have to be manufactured incorrectly right? Solution would be to taper the shim? I’ve never heard anyone checking Y on a 2 axis lathe. I’d like to know how if that’s what you mean.

Re: turning to center, we have discussed this with service people a lot. We had no issues turning to center, BUT... when looking at our standard stick tools, they almost all stick out from the turret approximately to the center of the boring bar holders, which puts them back on center. So we should be ok.

OK, well there is your problem.

Your machine is not designed to have the stick tool pockets aligned squarely.

If the tool is on C/L at "stick-out" then your pockets are on a slight angle for whatever reason, which is fine - as long as you indicate to the drill holder.

On the other hand, you said that you were not repeating well at first. (on OD pockets I take it)
Or was it that you was having issues with a tool that did NOT stick out very far, and the 1" and 12" OD's were way off compared to each other?

With your tools sticking out - you can face to C/L?

Also - if your stick tools and your drill holders don't agree, don't blame the curvic coupling, tapered pins, or any other such thing that is beyond the one single pc of metal that the dis-agreeance is within.

-----------------

Think Snow Eh!
Ox

wmpy · Jan 2, 2021

Ox said:
OK, well there is your problem.

Your machine is not designed to have the stick tool pockets aligned squarely.

Have you ever seen a machine that wasn't designed to have them aligned? I haven't, and I can't think why anyone would want that. To have the tool be at Y0. only at a certain amount of stickout seems to be very limiting although livable for basic operations. What if you have a really long stick tool like a cut off tool? Or if you have a double boring bar holder? It seems, as the O.P. suggests, that there was an error made when the machine was built.

tntcustom, am I right that the correct shim size would be 0.120" thicker? That seems like more than a small mistake to make.

Ox · Jan 2, 2021

No - I haven't, but then I only have worked on the few machines that I own, so ....

The crash didn't move 1/2 the pockets in the turret, and if you shim the turret up .120 to git the stick pockets square, then the drill holders will be .120 too high eh?

As long as both of those are in the same chunk of metal, I don't see this changing.

---------------

Think Snow Eh!
Ox

Hardplates · Jan 2, 2021

Ox said:
No - I haven't, but then I only have worked on the few machines that I own, so ....

The crash didn't move 1/2 the pockets in the turret, and if you shim the turret up .120 to git the stick pockets square, then the drill holders will be .120 too high eh?

As long as both of those are in the same chunk of metal, I don't see this changing.

---------------

Think Snow Eh!
Ox

Shimming the turret up and indexing the curvic coupling should allow the pockets to be able to be parallel to the X axis and the tools to be on spindle centerline.

The curvic should be adjusted so the pockets are parallel with X and then the turret shimmed to bring everything to spindle centerline.

When I first relied to this thread I ASSumed the machine was in proper alignment from the factory, which appears may not have been the case.

wmpy · Jan 2, 2021

Yeah, I think everyone assumes that their machine will be properly aligned from the factory. And rightfully so!

But I think the OP is looking to see if anyone can come up with any other possible explanation before blaming the machine maker.

Ox · Jan 2, 2021

OK, I re-read, and he does NOT say how far out the stick pockets are, but the drill pockets are .120 "out", and I guess that we need to ass_u_me that he means that it is "out" in the "low" direction?

But I guess he doesn't say how far out the stick toys are once they are square.
I had in my head that the drills were on C/L and the pockets were low when square, but I guess that's not the case.

So - yeah, I guess a .120 shim under the whole turret does seem plausable.

Either way tho - it's not the coupling, and simply something that they just realized, and not something that is expected to be broken.
... and can be worked around by keeping stick tools roughly the same X as the drills I guess.

-------------------

Think Snow Eh!
Ox

yardbird · Jan 2, 2021

Hardplates said:
Something else also tells me that on this machine the turret and spindle are not on parallel planes. IE a slant bed machine with a spindle mounted on a horizontal plane. Getting everything lined up on such machines can be a PITA to say the least. Just because the spindle is parallel to the Z axis does not mean the spindle plane intersects the x axis plane at the correct location.

I'm all in on this ^^ is the root of problem.

My guess is post crash the casting isn't setting in the same place on the X axis slide. Can you visually see separation or shift of the machined surface on the casting where it mates up to the slide? As Hardplates mentioned you can have everything squared up with the world but if the turret doesn't intersect the center of spindle line in the correct location it will appear the "Y" or height is off.

I have never seen clear step by step instructions on how to correct this intersection of planes in the correct location problem. Specifically where to start first?

Stick tools will be more forgiving than X center line cutting tools. I've made special center drill sleeves on the machine with a drill and a reamer mounted in the chuck.

Who is Mike Cope?

Brent

Hardplates · Jan 2, 2021

yardbird said:
I'm all in on this ^^ is the root of problem.

My guess is post crash the casting isn't setting in the same place on the X axis slide. Can you visually see separation or shift of the machined surface on the casting where it mates up to the slide? As Hardplates mentioned you can have everything squared up with the world but if the turret doesn't intersect the center of spindle line in the correct location it will appear the "Y" or height is off.

I have never seen clear step by step instructions on how to correct this intersection of planes in the correct location problem. Specifically where to start first?

Stick tools will be more forgiving than X center line cutting tools. I've made special center drill sleeves on the machine with a drill and a reamer mounted in the chuck.

Who is Mike Cope?

Brent

Wes Johnson did a pretty nice short series on lathe alignments

Complete CNC Lathe Alignment - Part 1 - Leveling - YouTube

It's a shame he only plays with cars now cause he had a lot to offer as machine tool tech.

Anyway you don't know who Mike Cope is ???!!!!!!

It's ok, I haven't the slightest clue either.

yardbird · Jan 2, 2021

Hardplates said:
Wes Johnson did a pretty nice short series on lathe alignments

Complete CNC Lathe Alignment - Part 1 - Leveling - YouTube

It's a shame he only plays with cars now cause he had a lot to offer as machine tool tech.

Anyway you don't know who Mike Cope is ???!!!!!!

It's ok, I haven't the slightest clue either.

I did "watch Wes work" on the turret but I don't remember that machine having this plane outta whack issue.

If I remember correctly he mentioned this problem and kinda glossed over it quickly but didn't dive into it too far. That was my whole reason for watching the turret videos.

Rob mentioned "herth" whatever that is? He may know the non amateur way to go about this but I haven't seen where he expands on it either.

I'd like to hear biker go in detail on this subject. People know what could be wrong but nobody says how to properly do the job, specifically where to start?

When I did this job in the passed after I squared up the face then I aligned the stick tool pocket parallel to the X axis, adjusted the boring bar center location with the number and then run it that way. Made a few bastard holders and that was good enough for the girls I went with. Everything don't have to be perfect to use the thing. I've run some pretty beat up shit that made good parts.

Mike Cope must be the man?

Brent

wmpy · Jan 2, 2021

yardbird said:
I'm all in on this ^^ is the root of problem.

My guess is post crash the casting isn't setting in the same place on the X axis slide. Can you visually see separation or shift of the machined surface on the casting where it mates up to the slide? As Hardplates mentioned you can have everything squared up with the world but if the turret doesn't intersect the center of spindle line in the correct location it will appear the "Y" or height is off.

I have never seen clear step by step instructions on how to correct this intersection of planes in the correct location problem. Specifically where to start first?

Stick tools will be more forgiving than X center line cutting tools. I've made special center drill sleeves on the machine with a drill and a reamer mounted in the chuck.

Who is Mike Cope?

Brent

I didn't grasp what hardplates was saying at first, but I get it now. I've got a Hardinge lathe where the spindle is mounted horizontally like that. It's a pain to get aligned. And come to think of it, I think I only aligned it to the boring bar holders without ever checking if the tool pockets were parallel with the X. I might be in the same boat as the OP.

The OP has stated, though, that the spindle is mounted on a surface parallel with the X, so this likely isn't his problem.

CNC lathe turret cant be aligned ATTN MIKE COPE

Aluminum

Diamond

Diamond

Stainless

Aluminum

Diamond

Aluminum

Hot Rolled

Aluminum

Hot Rolled

Diamond

Hot Rolled

Diamond

Stainless

Hot Rolled

Diamond

Titanium

Stainless

Titanium

Hot Rolled

Similar threads