Taiwan lathe spindle runout

C

cloudrepair

DWG
Anyone have experience with these spindle bearings. The question can I get better than .0002 run out out of it. Im not sure I could chamber better then that if I can't get the lathe better then that. it seems the best I've been able to get so far is .0002 in the throat and .0003 in the base of the chamber. Thanks. I chamber through the headstock with a cat head I made for the out board and dial in the chamber throat and the muzzle. drill, bore and ream
 
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Is the spindle running out or are the bearings loose? Check the spindle with the chuck off, then put the indicator on the top of the spindle or the chuck and lift the chuck or use a 2x4 to lever it up and see how much it moves.

.0002 is getting pretty accurate for any lathe, especially if you are using the tailstock to drill and ream. If you really are getting .0001 taper, that's a lot to ask out of a small import lathe.
 
The little experience I've had with Taiwan lathes is that if the lathe has tapered roller bearings similar to what used to be in automobile spindles they are adjustable similar to adjusting wheel bearings. Too loose and you get excess runout. Too tight and the bearings don't turn freely enough. Paul Dorsey had told me the way he adjusted his bearings in his headstock was to chuck up a half inch rod in his lathe chuck and then take and chuck the other end in a drill chuck in the tail stock. Place a dial indicator against the chuck face and then turn the tail stock wheel back and forth. If you got more than .0002" axial movement the spindle was adjusted too loose. I tried that and could barely turn my chuck by hand. So, backed the jam nuts off to where I could turn the chuck by hand. That seemed to work. You don't want them to tight, but you also don't want them too loose. Just my opinion and am sure there are plenty out there with more experience with this than me. Jerry Sharrett for example.
 
Mike Bryant said:
The little experience I've had with Taiwan lathes is that if the lathe has tapered roller bearings similar to what used to be in automobile spindles they are adjustable similar to adjusting wheel bearings. Too loose and you get excess runout. Too tight and the bearings don't turn freely enough. Paul Dorsey had told me the way he adjusted his bearings in his headstock was to chuck up a half inch rod in his lathe chuck and then take and chuck the other end in a drill chuck in the tail stock. Place a dial indicator against the chuck face and then turn the tail stock wheel back and forth. If you got more than .0002" axial movement the spindle was adjusted too loose. I tried that and could barely turn my chuck by hand. So, backed the jam nuts off to where I could turn the chuck by hand. That seemed to work. You don't want them to tight, but you also don't want them too loose. Just my opinion and am sure there are plenty out there with more experience with this than me. Jerry Sharrett for example.
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Thanks.Mike are you saying to pull or push the chuck with the tail stock spindle (with the rod chucked up in headstock and tailstock )with indicator on face of headstock.to measure movement in the z plane
 
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I have only put a indicator on the spindle and turned it and put pressure on it in the x and y plane not the z plane. I ream with a pusher I made and a floating holder and get about the same results.I haven't trusted my tailstock completely even though I have dialed it in.
 
TRA said:
Is the spindle running out or are the bearings loose? Check the spindle with the chuck off, then put the indicator on the top of the spindle or the chuck and lift the chuck or use a 2x4 to lever it up and see how much it moves.

.0002 is getting pretty accurate for any lathe, especially if you are using the tailstock to drill and ream. If you really are getting .0001 taper, that's a lot to ask out of a small import lathe.
Click to expand...

Thanks
 
cloudrepair said:
Thanks.Mike are you saying to pull or push the chuck with the tail stock spindle (with the rod chucked up in headstock and tailstock )with indicator on face of headstock.to measure movement in the z plane
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Pull and push. Yes and you have the idea. If you get it too tight though, loosening off the jam nut won't just make it looser as the bearings themselves are very tight on the spindle. You'll have to put a block of wood on the rear of the spindle and tap (more than likely very hard tap) on it with a dead blow hammer to loosen it. I'd shoot for .0003 to .0004" of axial movement and make sure the spindle turns easily. Check it first before you do anything though and see how much movement you have. That will give you an idea how much it needs to be adjusted or if it does.
 
my big Chinese made 16" grizzly gun smith lathe has less than .0002 run out. that machine is stout and a darn good lathe. My little new SB has at least .0002 run out. Crazy thing is, my little machine cuts a little bit better thread than my big machine.
Id love to have a third machine. Id like to have a 12 or 13" machine. I would probably buy a Taiwanese made machine, over another china made machine. My little SB is a Taiwanese made unit. great little lathe!! Lee
 
Mike Bryant said:
The little experience I've had with Taiwan lathes is that if the lathe has tapered roller bearings similar to what used to be in automobile spindles they are adjustable similar to adjusting wheel bearings. Too loose and you get excess runout. Too tight and the bearings don't turn freely enough. Paul Dorsey had told me the way he adjusted his bearings in his headstock was to chuck up a half inch rod in his lathe chuck and then take and chuck the other end in a drill chuck in the tail stock. Place a dial indicator against the chuck face and then turn the tail stock wheel back and forth. If you got more than .0002" axial movement the spindle was adjusted too loose. I tried that and could barely turn my chuck by hand. So, backed the jam nuts off to where I could turn the chuck by hand. That seemed to work. You don't want them to tight, but you also don't want them too loose. Just my opinion and am sure there are plenty out there with more experience with this than me. Jerry Sharrett for example.
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It occurs to me after I checked it out and found about .0006 axial movement and tightened it up to about.0004 (seemed pretty tight already) that I probably should have lossend it slitely and then tightened it. Still has just under .0002 movement on the spindle nose. So runout is acualy .0001 probably can't get much better? Without replacing bearings with the best you can get.
 
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cloudrepair said:
Anyone have experience with these spindle bearings. The question can I get better than .0002 run out out of it. Im not sure I could chamber better then that if I can't get the lathe better then that. it seems the best I've been able to get so far is .0002 in the throat and .0003 in the base of the chamber. Thanks. I chamber through the headstock with a cat head I made for the out board and dial in the chamber throat and the muzzle. drill, bore and ream
Click to expand...

Your just chasing numbers here, will the rifle actually shoot better if you reduce your chamber runout below what is already a very good standard?

Trying to reduce spindle runout to less than 0.0002" on a Taiwanese lathe is like trying to catch Fairies.

Which rifle builder on this forum would be unhappy with the results you are already getting?
 
I believe I can't correct my runout any more then I have if I can spin the spindle and get a .0001 movement one direction with a 360 spin and then a couple spins and get it in other direction.
With the three jaw adjustru buck chuck I use or a four jaw the best I think you could do is split the runout in half right? maybe I'm missing something
 
James and Curious, I believe he is chasing a ghost. Lot more things important than .0002 runout. My 10EE has 50 millionths bearings, but so what?
 
Having .00005 bearings is no assurance you can hold .0002 either. Enlarging a rifled hole with a drill bit could cause runout even if you bore the chamber then ream it.
 
TRA said:
Having .00005 bearings is no assurance you can hold .0002 either. Enlarging a rifled hole with a drill bit could cause runout even if you bore the chamber then ream it.
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The reason you single point bore a drilled hole is to bring the hole being back into exact trueness and capability of the lathe spindle bearings.
 
TRA said:
Having .00005 bearings is no assurance you can hold .0002 either. Enlarging a rifled hole with a drill bit could cause runout even if you bore the chamber then ream it.
Click to expand...

Thank you

Yes that is why I check my barrel alignment every time I complete any operation. I like to know where I am.

And thank you Jackie for all the info you have taken the time to teach others. My experience tells me it is sound info and the things I have read from you and many others has saved me some trial and error.
 
Mike Bryant said:
The little experience I've had with Taiwan lathes is that if the lathe has tapered roller bearings similar to what used to be in automobile spindles they are adjustable similar to adjusting wheel bearings. Too loose and you get excess runout. Too tight and the bearings don't turn freely enough. Paul Dorsey had told me the way he adjusted his bearings in his headstock was to chuck up a half inch rod in his lathe chuck and then take and chuck the other end in a drill chuck in the tail stock. Place a dial indicator against the chuck face and then turn the tail stock wheel back and forth. If you got more than .0002" axial movement the spindle was adjusted too loose. I tried that and could barely turn my chuck by hand. So, backed the jam nuts off to where I could turn the chuck by hand. That seemed to work. You don't want them to tight, but you also don't want them too loose. Just my opinion and am sure there are plenty out there with more experience with this than me. Jerry Sharrett for example.
Click to expand...


Mike,

Thank you for the tip, I wondered how to check the axial movement, this procedure sure is simple and quite effective. I like it better than adjust and run and check temperature of the bearing area. I checked my Taiwan made ACER 1236, it checked out real nice, inside 0.0002. The lathe has been good to me, never had to service the headstock besides oil change.

I checked the Taiwan made 80s Vintage Jet 1024, it was 0.001. Adjusted it down to 0.0002. Once I get the VFD conversion done I will see how this baby lathe works with that tighter axial movement.

Thanks for the tip again. And thank you for passing on to Butch the information on your HS tool.

Nez
 
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