Lathe Turret

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08-04-2017, 11:50 PM
hods1222

Lathe Turret

I am looking to design and build a lathe tool turret for my Graziano SAG12 lathe that I am converting to CNC. I have been looking for a small diameter tool turret for an economical price but have not found one that will suit my needs as most are too big for my swing on the lathe. I have been doing a bunch of research and have found various methods for accomplishing the indexing (Curvic Couplings, ratcheting, etc.) I am wondering if a SPRAG clutch or one-way bearing would work for this purpose. Of course it would only be able to rotate one direction but the ratcheting ones I seen seem to operate the same way. To me this seems like a clean, no-backlash, way to accomplish the indexing operations that are required for a turret. I suppose I missing something since someone hasnt tried it yet? I was looking at a 62mm outer race and an inner race that would accomodate a 30mm shaft. I would do one on the forward end and one on the aft end. Some of the specs are as follows..

CSK30 bearing
Torque capacity: 180Nm
Max overrunning speed: 4,200rpm
Bearing load dynamic: 11.7kN
Bearing load static: 6.45kN

thanks for your help in advance...
07-11-2019, 01:06 AM
GTOhlms

Quote:

Originally Posted by hods1222

I am looking to design and build a lathe tool turret for my Graziano SAG12 lathe that I am converting to CNC. I have been looking for a small diameter tool turret for an economical price but have not found one that will suit my needs as most are too big for my swing on the lathe. I have been doing a bunch of research and have found various methods for accomplishing the indexing (Curvic Couplings, ratcheting, etc.) I am wondering if a SPRAG clutch or one-way bearing would work for this purpose. Of course it would only be able to rotate one direction but the ratcheting ones I seen seem to operate the same way. To me this seems like a clean, no-backlash, way to accomplish the indexing operations that are required for a turret. I suppose I missing something since someone hasnt tried it yet? I was looking at a 62mm outer race and an inner race that would accomodate a 30mm shaft. I would do one on the forward end and one on the aft end. Some of the specs are as follows..

CSK30 bearing
Torque capacity: 180Nm
Max overrunning speed: 4,200rpm
Bearing load dynamic: 11.7kN
Bearing load static: 6.45kN

thanks for your help in advance...

Hello. Just curious, did you ever end up making this? I have actually considered a similar design using a slightly smaller sprag clutch but still the same idea. I’d love to hear how it worked out if you did finish it!
07-12-2019, 01:20 AM
hods1222

Re: Lathe Turret

Quote:

Originally Posted by GTOhlms

Hello. Just curious, did you ever end up making this? I have actually considered a similar design using a slightly smaller sprag clutch but still the same idea. I’d love to hear how it worked out if you did finish it!

I didn't end up going that way. I found a 8 position lio shang turret that was already to the point where I could integrate it. I am working on getting the hydraulic piece of it done for the locking and then probably drive the movements with a stepper or with the original hydraulic motor. It was intriguing to me to see if the sprag would work though and I would've done it but this turret came through for a good price.

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07-12-2019, 02:55 AM
GTOhlms

Quote:

Originally Posted by hods1222

I didn't end up going that way. I found a 8 position lio shang turret that was already to the point where I could integrate it. I am working on getting the hydraulic piece of it done for the locking and then probably drive the movements with a stepper or with the original hydraulic motor. It was intriguing to me to see if the sprag would work though and I would've done it but this turret came through for a good price.
Sent from my SM-G960U using Tapatalk

Gotcha sounds cool. I’m doing mine for a much smaller lathe (Emco Compact 5) that I completely redid and upgraded. I have all of the material and hardware and plan to start putting together in the coming weeks. I too plan to use a stepper motor to drive but I am still up in the air about how I want to keep track of it’s position. I considered a closed loop stepper or cam roller limit switches but will probably settle for an encoder on one end. If it works out I’ll share some pics. If it doesn’t, Ive made the design in such a way I could substitute a ratchet and pawl system but I really liked the idea of the sprag. I guess I’ll control it all with an Arduino or Adafruit or something.

Anyway, hope yours works out!
07-12-2019, 04:38 AM
hods1222

Re: Lathe Turret

Quote:

Originally Posted by GTOhlms

Gotcha sounds cool. I’m doing mine for a much smaller lathe (Emco Compact 5) that I completely redid and upgraded. I have all of the material and hardware and plan to start putting together in the coming weeks. I too plan to use a stepper motor to drive but I am still up in the air about how I want to keep track of it’s position. I considered a closed loop stepper or cam roller limit switches but will probably settle for an encoder on one end. If it works out I’ll share some pics. If it doesn’t, Ive made the design in such a way I could substitute a ratchet and pawl system but I really liked the idea of the sprag. I guess I’ll control it all with an Arduino or Adafruit or something.

Anyway, hope yours works out!

That sounds awesome. I would love to see some pics of it. I will take some pics of mine too.

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