Pen turning without mandrel

[dickm]

Over on the Myford lathe forum on Yahoo, a guy was asking how to make a precision bush to fit in the end of a pen tube for turning. Was it anyone off this forum?
Reason for asking is that the explanation of how it was used, and its advantages over a standard manual wasn't exactly clear; before commenting, it would be helpful to know a bit more.

 

[woodyturner]

You can turn pens with the bushes only by using a friction drive in the head stock put the busying in the ends of the pen part and fix it on the lathe between the friction drive and the revolving center and turn them down to the bushing one half at a time

 

[dickm]

Thanks Woody - that seems to be what the guy was suggesting; my doubts about it were:-
1. how consistent is the diameter of the tubes? Is it close enough for the bushings always to fit?
2. is the setup as rigid as using a full mandrel?
3. what is the advantage over a mandrel?

 

[cornucopia]

turning between centres is more rigid than a mandrel and reduces run out and mandrel flex.
some swear by it nd throw away their mandrels and others prefer to stick with the mandrels.

 

[woodyturner]

Thanks Woody - that seems to be what the guy was suggesting; my doubts about it were:-
1. how consistent is the diameter of the tubes? Is it close enough for the bushings always to fit?
2. is the setup as rigid as using a full mandrel?
3. what is the advantage over a mandrel?

All good kits tubes are very consistent but bushes do wear down and need to be replaced from time to time the setup is very ridged as Georgs said a lot of pen turners prefer to turn without a mandrel and just as many with it is just personal preference

 

[dickm]

Thanks for those comments/explanations. Since no-one has come forward to claim the identity of the poster on the Myford forum, it is possibly worth explaining why the original question was posed a bit strangely.
The Myford guy posted a question about making bushes for pen turning which suggested he hadn't much of a clue about using a metalworking lathe - didn't know what tool to use and was looking for totally unrealistic precision. After various people had tried to point him in the right direction, I thought it might be worth suggesting that getting a mandrel could be simpler solution and querying whether the bushing method was necessarily superior. Then got flamed by the original poster, with a number of dubious claims about the engineering inferiority of mandrels. Including one comment that was completely wrong. There's been a few other posts from him since which confirm that he hasn't got a clue how to use a metalworking lathe.
So, it seemed worth asking on here about the merits of the two possible systems, expecting (and finding) a more reasoned response
Might even be tempted to make some bushes just to try now.

 

[CHJ]

I turn up my own bushes, even started to make up a couple of larger diameter (more rigid) mandrels today for 8 & 8.5mm tubes, have still to turn the plain as opposed to stepped bushes for them. Don't know when the next 'round to-it' will arrive to finish them. Just seemed like a good idea and something different to do.