No Mandrel Question

[vernon]

I tired my first no mandrel pen turning this afternoon, but seem to be doing something wrong.

I purchased the dead center from the little machine shop and a heavy duty live center from Woodcraft. When I began turning, the live center did not seem to be turning. I would turn it by hand, but it did not seem to turn when the lathe was running.

Within a very short time, the wood blank was warm to the tough, and the bushing at the live center end was almost to hot to handle.

I only tightened the tailstock enough to keep the blank from spinning.

Any suggestions? Thanks in advance for any help!!

 

[skiprat]

Yep, tighten it some more. You will get the feel of it. I tighten mine so that if I hold the dead centre and try to turn the blank, it should be difficult but will 'just' turn if you get a good grip.

 

[leehljp]

The purpose of the live center on the tail stock is the same as using a mandrel. It should not "just touch", but be firmly in contact with the tubed blank enough that the live center is spinning, as is the case with a mandrel. I apply about the same amount of pressure on the blank as I do when using the mandrel, but of course not overtighten. The problem here is that some people do overtighten and getting the right description is purely subjective.

 

[Firefyter-emt]

You may want to really check that live center. I hardly apply any preasure on my tubes when I apply the CA and my live center still spins. With the bushings are in the blank you can add more preasure, but not a "ton" just like with the mandrel.

I still suspect the live center, if you have enough preasure "to make the bushings almost too hot to touch" you are building heat and to me the energy needed to make that heat in slippage should be more than enough spin the live center.

 

[Firefyter-emt]

Strange, it posted twice.. [:I]

 

[Randy_]

The problem may be the live center. The heavy duty LC is not the one that is recommended by most for turning pens. It is really designed for larger projects. There have been a few posts about folks having trouble with that live center and changing to the standard duty #1189 unit. Problem is they are packed so full of grease that it requires a lot of pressure to generate the friction necessary for the mandrel/ blank/bushing do drive the live center. I even had that problem with the with the 1189 LC and had to soak mine in some kerosene for a while to dilute the grease a little.

You might try putting a drop of CA on the tip of the live center before you press it to the bushing. That might create enough of a bond for the bushing to drive the mandrel. Another thing you could try is heating up the LC with a hair dryer to soften up the grease a little. I expect that if you can get the LC to run, the grease will loosen up after some running time and the problem may go away.