Anyone used sub-spindle as tailstock?

Hello all,

I have an Okuma LB300-W, with the W axis sub-spindle. Just would like some feedback from other lathe users on using the sub-spindle as tail-stock for longer work pieces. I have had some success just clamping up a piece in the sub-spindle and turning a center point on it, but keeping it tight to work piece can be a pain, as well as rigidity, etc. Has anyone else tried using something else? Like maybe one of the spring loaded live centers? and if so, how to get it on center?

Or, does someone have a different method they've had luck with? Please share here, doesn't have to be an Okuma lathe :)

It is a bad idea to use the sub spindle as a tail stock. A tailstock has more thrust than a W axis and it also has a clamp to hold it in place. A W axis will rely on the motor to hold the force. If you exceed the duty cycle of the W axis motor the machine will alarm.

You can do it in a pinch with the sub or with the B-turret. You will want to use the torque skip feature that should be standard on any sub-spindle machine.

G22 W0 PW=45 D.1 L.15 F50

This will feed toward W0 at 50IPM (G94 active) reduce the feed .1 in front of target and feed until it contacts the part and reaches 45% load. It ca travel up to .15 past target before alarm occurs.

To use B-turret program PZ not PW. Adjust variables as needed for your machine.

You will not overload the axis and will always contact the part.

Yes a tailstock will deliver more thrust but this works too.

Best regards,

how to get it on center?
mechanical adjustment and nothing else. Machine must be leveled properly - first of all. Coaxiality of spindles is only mechanical issue

I've always just used the collet on the sub to grab the od of the part. I don't see why you couldn't put a center in it, I know the new mori nl's used a servo on the tailstock just like a sub to put pressure on the center.

LB 3000/4000 series has (as a standard ??) nc tailstock. it is driven by the servo motor and does not have a brake, hydraulic clamp or etc. it is also held by the motor only - works ok. You should be able to use torque skip function for the sub spindle also - same like for pickoff. im only not sure how to program synchronized rotation for both spindles...

LB 3000/4000 series has (as a standard ??) nc tailstock. it is driven by the servo motor and does not have a brake, hydraulic clamp or etc. it is also held by the motor only

Trust me there is a brake/Clamp, If you want to test this, Put a shaft in the machine, then turn off the power at the mains. The shaft will not fall out as the tailstack clamp is working

brake on the motor - ok, clamp - no. if You will take out the covers from W axis You can see whats inside. please do it.

Hello guys

I need your quick help, please... I have Okuma LT10-M lathe, and have a problem with W axis CAL command. When WB axis comes to main spindle to grab the piece, I want to stop the machine there and do a CAL function to use that position as a position where the the machine will grab every piece at desired load (85% for example). I do RESET, than go to "Zero point" screen and highlight "Zero offset" parameter for WB axis. When I press CAL, alarm "CAL command impossible" occurs. I've check the manual and it says I can't do a CAL function when main program is executing and they suggest to reset NC or wait for main program is finished. But with RESET button, my main program is stoped ... And I've tryied with shutting off machine, still the same...

When I use SET function, it works fine, but when I want to use CAL function, it's impossible. I have 4 Okuma LT10-M machines, on other 3 it works fine, but here... No... :/

What do you think? Maybe some of the limits are not god, or maybe some of the offsets?

Thanks in advance!

Best regards,
Samir

Anyone used tailstock for drilling or Grinding brooch at 25000 rpm ? ooo, or as a platform for ....pfff, i don't know english word :)

Well, 2nd spindle is more likely to be used as a tailstock, rather than machinig on it :))

Two spindles and 1 turret means simple parts - hope you have parts for that lathe :) Two spindles are more recomended for multus serie, because the "turret" can rotate, and it holds one tool at a time :) ... so turet volume stays the same, but is not for holding 12 tools, but only one ... so is stronger. More power, and you also can flip the parts :) ... on a lathe, with 2 spindles, you can't go that far. So, go ask your question to the guy that bought that machine :)


You can leave ~200 mm between 2nd spindle and part, and use a passive dispositive in between - a double thread that expands both ways.You expand it by hand, so you fill the tension.
Look at attached photo - that is a traction anchor ... what you need is to make it work in an opposite manner.
So, 2nd spindle stays in one place, it does not move left-right, and you can disperse the presure on its frontal ... i don't think you will break something :) just tension it right :)
You can consider that dispotive as a " frontal antrenor / frontal claw / v shaped like a normal tailstock " on the left, and as " clilindrical or flange" on its right.
You can also use a live centrer like that :)
You need even more power ? replace the 2nd spindle with such a thing :) ... and so, you have more stability on right side :)

* this answer is not a must, is just an idea :)