Mandrel problems

[lpacphantom]

I'm a relatively new turner, been about 4 months or so, which means I'm still learning some of the dos and don'ts of turning.

I noticed recently that the mandrel I'd been using from the beginning was not perfectly lining up with the mandrel saver I have in the tailstock. It didn't seem to be affecting the quality of the pens until recently I've started to notice that I'll be flush with the bushings on one side, but not on the other.

So, I bought a brand new mandrel, thinking it was the mandrel that was off true. But the brand new one had the same problem right out of the gate. Could there be a problem with the headstock that is causing my mandrels to be slightly tilted?

Any help in troubleshooting this is greatly appreciated. Thank you.

 

[Paul in OKC]

How do you square the ends of your blanks? That can cause an issue. Also if your bushings are loose on the mandrel. In sanding you also may have different density of wood grain from one side to the other. IMHO, the mandrel not being perfectly lined up is not an issue. Lots of discussion on this with different opinions. Your mileage may vary.

 

[thawkins87]

I'm not an expert but I would think a more likely culprit would be your tailstock rather than your headstock... not sure if you can adjust it on your lathe or not to get it perfectly trued up.

If you completely seat the mandrel in the headstock and turn on the lathe at a very slow speed without the mandrel saver on it, does it rotate noticeably out of alignment?

 

[JimB]

Check to see if your headstock and tailstock are aligned. Put your drive center in the headstock and live Center in the tailstock and bring the 2 points together. They should line up perfectly.

Also check that your Morse tapers are clean. Anything, even sanding dust, can cause your mandrel snot to seat correctly.

 

[leehljp]

A common problem with new to wood lathe users: Wood lathes come with a more pointed tail stock center meant for wood. Mandrels are, of course, made out of metal. The dimple in the mandrel REQUIRES a 60° tail stock center. If you don't have a 60° center, the more pointed wood center point will wobble in the mandrel, often causing the point to bend or ball up. Very small bend or ball, but it is enough to cause a wobble.

Not sharp enough tools usually causes a new user to apply more pressure which can add to the bending of a mandrel.

There are numerous things that can cause out of alignments, and most but not all are from mandrels. For this reason, many use the TBC or turning between centers without using a mandrel. . . Just another choice that can be made.

 

[lpacphantom]

How do you square the ends of your blanks?

I use a disc sander with one of these. I didn't have good results using a barrel trimmer, and this seems to work much more consistently.

does it rotate noticeably out of alignment?

Yes, the tip of the mandrel is clearly out of center.

@JimB, I will check this later.

 

[dogcatcher]

A picture of your set up would be a lot of help. One thing I have found, is that problems are usually self inflicted, better known as operator error. You being new to the lathe, it is a good chance it your "machining" method.