turret crash Nakamura lathe

the spin doctor · Jul 10, 2010

My new Nakamura-Tome Slant 3 lathe locked up when I mounted a toolholder on a position that did not clear the back of the machine when the turret rotated. I believe the prior owners removed the taper pins because now the turret is half way between positions and will not stop rotating when looking for a tool position. I know how to take apart the turret but wonder if there is a way to move it without dissassembly?

Thanks
Keith

Ox · Jul 10, 2010

The tapered pins are s'posed to be pulled for production - and only used for alignment.

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Think Snow Eh!
Ox

the spin doctor · Jul 10, 2010

Ox, Yes the removal of the tapered pins has been the subject of quite a discussion in the past. I like having mine out but this new machine is so much bigger than my old one, I was hoping of some way of using a lever. I guess I will start to tear it down tonight and get it fixed properly. Hate learning the hard way but I will never mount the toolholder in the wrong place again!

Pipes · Jul 10, 2010

Shrink fit coupling slipped

From the sound of it the crash most likely caused the shaft to rotate on the shrink fit coupling to the motor. This is corrected from the back side of the turret (right side as you look at the slant).

You will need to manually unclamp the turret and loosen the 16 or so bolts on the shaft coupling to allow realignment. There should be clear instruction in your manual correcting this type of problem.

metaltech · Jul 10, 2010

If the tool hit during the head indexing, then by definition, the turret wasn't clamped, so the pins would be irrelevant. If it indexes continuously, then whatever senses the shaft position is the problem, or related to it.

wippin' boy · Jul 11, 2010

i rarely put the pins back in after the first wreck on a machine
that being said if this was true

The tapered pins are s'posed to be pulled for production - and only used for alignment.

they would pull them out when they install a new machine
and they don't

the spin doctor · Jul 11, 2010

metaltech said:
If the tool hit during the head indexing, then by definition, the turret wasn't clamped, so the pins would be irrelevant. If it indexes continuously, then whatever senses the shaft position is the problem, or related to it.

With the turret off of the machine, can see that the drive mechanism for the live tooling is about one half station off. Maybe it is a simple matter of the curvic coupler being disengaged and the turret stopped when it hit during indexing. So the turret jumped some of the cogs in the coupler rather than bothering the taper pins?

Thanks

the spin doctor · Jul 11, 2010

Pipes said:
From the sound of it the crash most likely caused the shaft to rotate on the shrink fit coupling to the motor. This is corrected from the back side of the turret (right side as you look at the slant).

You will need to manually unclamp the turret and loosen the 16 or so bolts on the shaft coupling to allow realignment. There should be clear instruction in your manual correcting this type of problem.

I found a discussion in the manual with exploded diagram concerning a crash of the turret with the spindle, tailstock or part when alignment needs to be done and taper pins removed etc. However, there is no discussion of what to do when the turret hits the back of the machine during indexing. This machine has two holders that are oversized and when they are mounted on the the outer positions, they hit the back of the machine during indexing. I believe I am correct in assuming that I just have to remove the bolts as I have done and rotate the turret back into position about a half station. The problem must be that the curvic coupler jumped a couple of teeth. I think Metaltech is correct when he suggested that the taper pins are ok. I'll give it a try when I can get some help to hoist the turret head back into position. Sure feel more confident being able to discuss it on this website. Thanks everyone!

the spin doctor · Jul 11, 2010

I guess the fix of this problem is more difficult than I thought. I can't get alignment of the turret head with the bolt pattern and the live tool drive head. I stopped the turret by initiating an index and shut off power during the change in an attempt to get the mechanism to disengage. This was how my Mori manual described the process of alignment. At this point the turret freewheels and will only stop by turning off power.

Since I have a part in the chuck with a 1 5/8" hole drilled in it when the accident happened, I could slide the turret into position without the bolts that hold it on. I could then put a 1 5/8 aluminum shaft in the tool 1 empty hole of the turret where the holder would mount. Then align the shaft in the part at the proper X offset with the MPG. Then I could index to tool 1 and hope the bolts line up. The shaft is large enough to hold the turret head on the mounting shaft. I don't see a safety issue and don't see that anything would be damaged by trying.

Anyone have any other ideas?

Thanks!

Edster · Jul 11, 2010

Might be time to get a service tech out there to re-align. Watch what he does and you'll know how to fix it next time.

the spin doctor · Jul 11, 2010

Edster said:
Might be time to get a service tech out there to re-align. Watch what he does and you'll know how to fix it next time.

That would be nice, but I usually can't get a tech to the shop for weeks. Last time he was in my shop it took 11 hours to align everything on the old machine and $1100 later (the next day) the machine died. I plan to ask to get on the schedule for a repair in the morning. It can't be that difficult to fix, especially since the removal of the turret head is the most difficult part of the job. I just hope I can fix it myself in the meanwhile. Besides, what fun is having someone else fix it when I can waste hours, suffer bruises and cuts and finally experience the elation that comes with such an accomplishment?

the spin doctor · Jul 11, 2010

Now I feel better. Found instructions in one of the manuals! The repair requires manual actuation of the clamping solenoid to unclamp. Then the end of the turret has to be exposed to remove the dog collar, loosen 18 screws, realign the #1 tool dog to the proximity switch and reassemble. Not a difficult job but had to buy all new extra long allen wrenches and allen sockets. A good investment and a lot cheaper than a technician - hope it works. I will know by morning...

Thanks!

the spin doctor · Jul 11, 2010

Followed manual instructions and the only problem is that I can't manually turn the turret head inspite of actuating the unclamp solenoid and loosening the 18 screws that release the pressure from the shrink fit coupling. I can hear the clamp solenoid working when it activates but that turret head is still locked and even using a long bar for leverage. Hopefully I can get a trick from someone at Methods tomorrow.

the spin doctor · Jul 11, 2010

Pipes said:
From the sound of it the crash most likely caused the shaft to rotate on the shrink fit coupling to the motor. This is corrected from the back side of the turret (right side as you look at the slant).

You will need to manually unclamp the turret and loosen the 16 or so bolts on the shaft coupling to allow realignment. There should be clear instruction in your manual correcting this type of problem.

Yes, you are correct. I found the instructions but can't get the turret to unclamp enough to move it by hand...

Thanks

machtool · Jul 11, 2010

G’day Keith

the spin doctor said:
and loosening the 18 screws that release the pressure from the shrink fit coupling.

Those locking shaft couplings kind of self lock,just because of the low angle they work at. I’d try putting 3 or 4 of the bolts back in the tapped holes that pull the coupling together, but leave them 3 or 4 turns loose. You might have to use longer bolts. Then give each bolt a gentle tap with a soft drift, to push to locking taper back. Work around the coupling in a few places, hence the 3 or 4 bolts.

Regards Phil.

{Adding on edit} Not sure if this applies to you or not, quite often you have a few tapped holes, in between the 18 screws you have. In that case you can loosen all the bolts then use a few to jack the coupling apart.

metaltech · Jul 11, 2010

I'm reading this well past your postings, so it looks like you're on your way to solving the trouble.

Does this turret actually move away from the toolpost base to do its unclamping, so that you see it push out .4' or so? Some newer turrets do the clamp/unclamp internally, and it's not visible. Either way, there should be a sensor that reads "unclamped". You'll be able to see its status on a diagnostic screen. That could confirm is it's unclamped or not. Keep in mind, just because it's unclamped, you might still not be able to rotate it by hand. It depends on the indexing mechanism, which you haven't mentioned. Some old machines use a Geneva mechanism, which you will not be able to move. Others are geartrains driven by a hydraulic or electric motor. Some of these are too hard to move, but others can be moved. Newer turrets tend to be driven by a servo motor, and probably can be moved by hand.

I would definitely call Methods and talk with one of their techs about this procedure. Even if they charge you for the consultation, you'll learn what you need to know waaaaaay faster and with less aggrevation than just turning bolts until you stumble across the solution. Geez, I do this for a living, charging hourly, and even I don't want the job to take longer than necessary.

PHDesigns · Jul 12, 2010

Hey Keith, give me a shout when you have a chance. Don't know if I can be of much help, but will give it a go. We have had to realign the turret on one of our machines in the past, so.....
Paul

the spin doctor · Jul 13, 2010

Paul, I don't have your number, can you call my office from the phone book?

the spin doctor · Jul 13, 2010

I got the shrink fit coupling to release and realigned nicely until I indexed the turret, then it moved about 1/2". Perhaps I did not get it tightened enough. I tried a second time and the same thing happened, then something happened electrically. Now it will not index and the solenoid is locked and cannot be worked manually. There is also a red light lit on the solenoid body.

Thanks
Keith

Ox · Jul 13, 2010

If you take the solenoid off the valve stack - you can manipulate it manually with a standard magnet. (of reasonable size)

---------

Think Snow Eh!
Ox

turret crash Nakamura lathe

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