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View Full Version : How to align spindle/headstock on my lathe



Steph dexter
02-18-2016, 11:17 AM
Dear all,
Im a new member and new lathe user.

I had a terrible terrible accident this afternoon when testing my Chinese lathe, the cutter bumped to my chuck until stop and causing the spindle missed alignment.
Quickly taking off the chuck and the adaptor, and start measuring with dial indicator.
And the spindle is not running straight/ align anymore.

A local service suggesting to replace the spindle bearing and charging high price for his service. But Im not convinced 100%...
what should i do?

Really hope i can get guidance to fix my lathe spindle.





Btw here are the video

View My Video (http://tinypic.com/r/xatpn6/9)


and this is my chinese made lathe

http://i63.tinypic.com/ziuigw.jpg

is there anyone here got the same lathe and or familiar with it?

Carm
02-18-2016, 11:48 AM
Invalid test. Did that lathe come with a taper center for the headstock? If so, install, seat and run the indicator on the OD.
If not, run the indicator just inside the spindle hole.
Let us know what the indicator reading is, whether mm or inch.

RichR
02-18-2016, 11:51 AM
I think the spindle is running way too fast in that video for the dial indicator to keep up. Try slowing it down to the 100 to 200 RPM
range. Hold the camera steady or set it down on something. It's hard to tell in your video how much of the needle movement is
being caused by run out and how much is caused by vibration.
While you have the dial indicator set up, grab the spindle (motor off of course) and see if the needle moves when you push it in
and pull it out of the headstock.

danlb
02-18-2016, 11:55 AM
I did not watch the video because it required running java scripts from untrusted web sites. I don't own that lathe, though I've seen many like it.

Your post suggests that you find measurable movement of the spindle bore using a dial indicator. If that's the case, the bearing or the spindle is bad.

Is the highest spot of the taper always at the same spot relative to the spindle position, or does it shift with each rotation of the spindle? If it shifts, I'd suspect bearings.


Dan

J Tiers
02-18-2016, 12:03 PM
Are you sure the spindle is not straight?

In your video, you have something attached to the spindle, so it is not clear that the spindle is bad. The part attached to the spindle could be causing the indicator change.

I see about 0.1mm change of indicator reading ( the indicator is hard to see in the video). But you are not directly checking the spindle.

use an indicator and check the surface the chuck mounts to as you slowly turn the spindle by hand. (it is best to turn slowly by hand when using the indicator. Running with the motor is not a good idea)

Also check the inside of the spindle. Put the indicator tip against the inside of the spindle, from the side. You have to be careful but it can be done.

if the indicator shows a change of reading as the spindle turns, then yes it may be bent.

If the spindle is bent, it may need to be replaced. Maybe the bearing also.

If that is not possible, maybe the chuck mounting surface can be machined flat again so the chuck can be used for a while, if the bearing is not damaged. Some chuck mounts may not allow that. I don't know if your chuck mounts with bolts or with a cam type lock.

Mcgyver
02-18-2016, 10:47 PM
if you want to measure run out, turn the power off, get a quality tenths indicator and rotate by hand. The video wasn't clear to me or maybe its my browser, but sorry, you may be pooched. put a 10ths DTI in the spindle nose and see what you get

J Tiers
02-19-2016, 12:17 AM
if you want to measure run out, turn the power off, get a quality tenths indicator and rotate by hand. The video wasn't clear to me or maybe its my browser, but sorry, you may be pooched. put a 10ths DTI in the spindle nose and see what you get

he's in a metric country..... that will be a 0.01mm indicator. he could probably use a 0.05mm indicator just as well, if the problem is as big as it looks in his video. I can't see what his is, the image is stretched (different TV standards, probably)

As best I can tell with the lighting and stretching of the image, he has the tip of the indicator axial to the spindle, on an end surface of whatever is on the spindle. So he is really reading "cam" movement, or axial runout, and not radial runout.