Mini lathe headstock out of round?

[Phil Landwer]

My 3 year old jet mini lathe seems like the headstock has gotten out of round. I don't think it's the chuck....but how can I tell which it is, for sure? I've tried a couple of pen mandrels in it, and they both wobble...

[Ken Fitzgerald]

I would use a dial indicator with a magnetic base and check the runout on the spindle.

Pen mandrels get wobble easily due to too much pressure applied to them. Don't ask me how I know this.

[Mike Cruz]

Phil, I have a sneaking suspicion that you are talking about the spindle, not the headstock. I think it would be pretty safe to say that ALL headstocks are out of round. Now, that you have issues with your spindle is another story. Ken's advice seems sound...

[Michelle Rich]

if you don't have a dial indicator..do you have two live centers? Put in headstock & tailstock and pull the tailstock into meet the one in the headstock. Meet? spin the headstock pindle & look for wobble. BUT I doubt it's your spindle..the pen mandrels are probably 98% of your problem

[Roger Chandler]

It is most likely your pen mandrel that is out of round.......they flex and bend due to tailstock pressure, and I had to replace mine because of that issue.............

I now have one where a live center will go over the mandrel and put pressure on the bushing and not the mandrel......it eliminates the out of round mandrel...........great tool.

http://www.pennstateind.com/store/PKMSTS2.html

not likely your spindle went out of round unless you have a bad bearing.

[Phil Landwer]

if you don't have a dial indicator..do you have two live centers? Put in headstock & tailstock and pull the tailstock into meet the one in the headstock. Meet? spin the headstock pindle & look for wobble. BUT I doubt it's your spindle..the pen mandrels are probably 98% of your problem

Couldnt this test also indicate the tail stock is out of round?

[Phil Landwer]

It is most likely your pen mandrel that is out of round.......they flex and bend due to tailstock pressure, and I had to replace mine because of that issue.............

I now have one where a live center will go over the mandrel and put pressure on the bushing and not the mandrel......it eliminates the out of round mandrel...........great tool.

http://www.pennstateind.com/store/PKMSTS2.html

not likely your spindle went out of round unless you have a bad bearing.

Ive tried more than one mandrel now, and they all wobble.....slightly.
how do I know if it's the headstock bearing, or the chuck?

[Jim Burr]

What kind of chuck Phil? Pen mandrels are just south of useless. Head bearings will make a lot of noise as they degrade, but it's possible they started out mis-aligned...unless it just crept up on you. I'd check out the run out on your chuck before shooting the headstock...and dump the mandrel!

[Marvin Hasenak]

What kind of chuck are you using a chuck to hold the pen mandrel?

[Phil Landwer]

It looks like a drill chuck. Does that make sense?

[Marvin Hasenak]

Make sure the jaws in the chuck clean, I would open the chuck up and blow it out with compressed air. Last resort, is the MT of the spindle and on the chuck clean? If it ran true before and now it doesn't and your mandrel is straight, then I haven't a clue what the problem is.

[Ken Fitzgerald]

I would also recommend cleaning the interior of the morse taper on your spindle.

Any wood chips/dust that might get in there while changing devices can cause any tool using the morse taper to not seat properly and to become offcentered. They actually make reamers out of non-metallic materials that can be inserted into the morse taper and rotated to clean/ream it. You don't want to remove metal just any foreign material.

[Darren Jamieson]

Not to steel the thread but I have also had similar issues. (not with pen mandrels) I did change the bearings to a much better bearing and I spun the shaft on a metal lathe and it was quite true. My chucks are both Nova (G2 & G3) but I still seem to not be able to get something truly round. Noticed mostly when trying to hollow, I get alot of chatter.