Bushingless Penturning

[scroller99]

I have read in the posts when my fellow penturners have told others to throw away there bushings and use a caliper, this isn't my question, how are you guys holding the pen centered on the mandrel for turning? a 10mm tube on a 7mm mandrel leaves a little slack to play with. The only solution I can think of is making 2 tapered bushing out of corian that would run from 7mm to maybe 12mm? Am I on the right track? What does everyone else do? thanks Howard

 

[fiferb]

I don't think they are being literal when they say throw away the bushings. Just don't use them exclusively. Use the bushings as a guide to get close to the correct size and then measure with calipers to get it exactly as the corresponding hardware.

 

[rherrell]

I don't think they are being literal when they say throw away the bushings. Just don't use them exclusively. Use the bushings as a guide to get close to the correct size and then measure with calipers to get it exactly as the corresponding hardware.

Correctamundo!:biggrin: I don't use a mandrel but even when I was I would use the bushings to get close and then change my set-up. I'd remove the mandrel, put a dead center in the headstock, live center in the tailstock and mount the barrels ONE AT A TIME and WITHOUT the bushings. Then I can SAND them down the rest of the way without any interference from the bushings.:wink:

 

[GoodTurns]

no mandrel used! simply set the blank (with bushings) between the live and dead centers. Many do not use the bushings FOR MEASUREMENT. The bushings hold the work while turning, but calipers are used for final sizing. Alternatively, you CAN skip the bushings and just press the centers into the tube, but this leaves you very susceptible to stretching the tubes at the ends (unless you are a VERY light turner!).

 

[leehljp]

I will add for those reading this thread -
• "Mandrelless" does not mean "bushingless".
• "No Mandrel turning" does not mean "No bushing".

And to repeat what has been said above, I measure with calipers for sizing the blank, not bushings. This does not mean that I don't use bushings to hold the blank, because I DO use bushings to hold the blank; I just don't use a mandrel to hold the bushing.

I don't recall reading anywhere to throw away the bushings, i.e. not use them, or even figuratively throw them away. I have read to throw away "bad" bushings - that are drilled off center or are out of round.

 

[Russianwolf]

what these guys said. The one tricky one is the 7mm kits as the stock bushings can't be used for mandrel-less turning (nothing to orient the tube to the bushing as the bushing doesn't fit inside the tube) so you either 1) have to find someone who makes custom bushings for you. Johnnycnc makes great bushings but the flood put him out of business for the foreseeable future. or 2) make your own bushings out of delrin, or some other material. The important thing is for the portion that slides into the tube to be tight enough to prevent slop. 3) turn them between centers, without bushings. just be careful to not apply too much tailstock pressure and deform the brass and split the material as mentioned above.

Bushings for all kits larger than 7mm (and a couple of the B mandrel kits) can be used for between centers (mandrel-less) turning since they are stepped and slide into the tubes.

 

[scroller99]

okay I have the drift now and never thought about turning just between the centers on the lathe, now I have a project to work on! as soon as I get my new ca I will be in the shop turning! thanks a million guys I really appreciatte it! Howard

 

[leehljp]

I should have posted a picture but forgot that I had one. Here is a pict of my first trial at dead drive mandrel- less turning. The pict below shows the final stage in which I am "finishing" it without the bushings. I DO use the bushings to turn it to near size.

http://www.penturners.org/photos/images/940/1_Dead_drive_1.jpg