Mandrel Issues

[daveeisler]

I have been experiencing wobble or vibration of the right bushing , while mounted and spinning with a blank between them, by right, I am referring to the bushing closest to the tail stock, I find no matter what I do, I get noticeable vibration from the right bushing, here is what I have done so far, I got a new mandrel, that has an adjustable length, and I made it short, where I only turn one blank at a time, I have a new tail stock, I have the Penn State mandrel as well, that does not require a nut on the end, if you are familiar with it, you will know what I mean, I have tried several different amounts of tension from the tail stock as well, my mandrels and tail stock are either Penn State or Woodcraft, is there a better quality, is there something I am missing?

 

[ldb2000]

The first thing that comes to mind is that your live center is either not 60 degree or just bad . If not that then you have an alignment problem between the headstock and tailstock .

 

[skiprat]

I reckon Butch is probably correct, but are your blanks nicely squared too?
Are the bushes a sloppy fit and loose inside the tubes?

 

[daveeisler]

Thanks Guys, I checked the head/tailstock on my Jet Mini, it appears to be in line from all around, I do not think I have 60 degree live center, also on my PS slide thru tail stock, the giude doues have movement to it, so I went back to the live tail, I will try a nee , 60 D. is it possible the end of the mandrel is worn,

 

[ldb2000]

If it's not a 60 degree then it's not fitting into the mandrel correctly and causing the wobble , the little hole in the mandrel is 60 degrees .
If you only used that mandrel I would say yes but you say you tried a couple of different mandrels so I would doubt it .

 

[Robert A.]

If you have the new live tail center from psi check the little crome tip.I got one of those when they come out and wish I hadn't.If you are useing the 60% tail center check the tip they will wear down.Good luck!

 

[toddlajoie]

I believe he's saying he has the PSI Mandrel Saver tailstock:

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

So if that thing has some play or wiggle to it, you going to be out of round. I've always wondered if it was possible that either the mandrel or the tailstock might wear over time, causing it to become loose. They have not been out for long, so unless you use it nearly non-stop since it came out, I doubt it should have worn out so quickly. Beyond what has already been discussed, are your bushings true and round? Any glue residue on the mandrel or bushings?

 

[daveeisler]

Todd, you are correct on the PSI Mandrel, that is just what I was using, and I have only done 25or 30 pens on it, and I only noticed the hole that is the guide for the mandrel is loose, I got it from Barry Gross , at a trade show, I do like it, or should I say, I did like it.

 

[toddlajoie]

Well, if you've got a set of calipers, measure the mandrel at a few spots along it's length and see if you notice it being significantly thinner around where the tailstock is, then the mandrel is wearing out during use. I've never used this tailstock, but it would be my assumption that it should spin with the headstock and material, so it should not really have the kind of friction to wear down that quickly. If the mandrel is consistent, the I would measure the inside of the tailstock receiver and see how much larger it is than the mandrel. Measure it at a few different points on it's rotation so you can see if it is out of round at all. If you have any questions about what size this is supposed to be, you can check with some other members here or PSI to see what it should be...

I'll also take this time to plug turning between centers. I'm a recent convert to this, and I have no intentions of ever going back to using a mandrel. All you need is a 60 deg dead center (around $11, http://penturnersproducts.com/index.php?main_page=index&cPath=5) and a 60 deg live center (around $30 if you don't already have one, same site) and you will never NEED mandrels or bushings again, just a decent pair of calipers (around $15-$50) and you can turn any kit you want. Bushings are a convenience and can make turning close to size easier and quicker to get close to size, but they are not necessary.