Lathe wobble / mandrel / head or tail stock

[flyguy245]

So I'm sure that this has been discussed in past forums and I have searched and read a few however that said I am having an issue that seems to have just started. I noticed that I was getting some vibration when turning pens and other items. Yes my tools are sharp. I even get it with brand new carbide tips. Kind of hard to describe other that it is like something is bouncing or the mandrel is bending causing a bounce. Thought maybe it was because I didn't have the ends squared up but have ruled that out. Here's the thing when there is no pressure on the head or tail stock things seem fine. Once I put a bit of pressure on to hold things I start to notice the problem. I have tried different mandrels and also a mandrel saver tail stock that is not supposed to put any pressure on the mandrel itself but the problem is still there. Could there be something out on the tail stock or a bearing in the head stock? It doesn't seem to take much pressure to make it happen. I have a Jet 1015vs. Any help would be appreciated.

 

[LK&T]

You have a difficult issue to troubleshoot because there are many, many causes of lathe vibration. That's not gonna stop me from taking a stab at it, though. The first thing I'd suspect is your mandrel. Try turning using a chuck or, even better, simple spindle turning between centers. If that controls your vibration, or at least reduces it, then your mandrel is wonky. If there's still vibration when turning between centers (TBC) then you have to check the lathe. I'm sure there's a lot of resources on the interwebs on how to check your lathe. Keep checking everything about the lathe until you find an issue or until you're satisfied the lathe is not the problem. After that, it would be a technique issue. Good luck!

 

[Pen Joe]

I you have a machinist dial indicator put it on the spindle shaft to check to see if its running smooth, if you don't have I would do a simple fix that might be the problem, change the bearings in the head stock.

 

[Paul in OKC]

Well, my first thought is the ends not squared. I think that causes more troubles than we think. But if that's not it..... Where along the mandrel does it 'bounce'?