question about turning between centers..

[TellicoTurning]

I see a lot of turners here tout turning between centers in lieu of the mandrel..

On bigger pens the bushings have an offset that is inserted inside the tube, but how do you handle the kits that have bushing that only butt up to the blank.. like the slimline..

While I can see the advantage on finishing, for me at least, it's more efficient to turn both pieces of the pen on the same mandrel at the same time.. it gives me a better feel of what the final pen will look like.

 

[rhahnfl]

I'm still a mandrel man myself. I guess it's just a matter of personal preference. I like the bushings also. I don't always turn exactly to them but they make a great guide to help you see the finished product.

 

[Texatdurango]

Originally posted by ozmandus

I see a lot of turners here tout turning between centers in lieu of the mandrel..

On bigger pens the bushings have an offset that is inserted inside the tube, but how do you handle the kits that have bushing that only butt up to the blank.. like the slimline..

While I can see the advantage on finishing, for me at least, it's more efficient to turn both pieces of the pen on the same mandrel at the same time.. it gives me a better feel of what the final pen will look like.

Then by all means stay with what you are comfortable with. As for myself, I haven't had a mandrel on my lathe in months. I don't think you'll convince anyone who has switched to switch back!

 

[Brewmeister35]

I switched to centers for a couple reasons. I kept having issues with the mandrel wobbling resulting in out of round turnings. I couldn't remove the blanks from the mandrel, put them back on, and have them turn the same again. I was having trouble sanding through the CA finish because of this. I tried turning with the mandrel and finishing between centers and found the barrels were not true and still had problems sanding through. That along with sticking the blanks to the bushings and having the CA crack while removing the bushings and the whole turning between centers idea became very attractive. I still use a mandrel to rough turn pretty much everything, then switch to centers to finish cutting and apply the CA finish. If I wasn't using CA for the finish, I'd still be using the mandrel for everything.

I don't see a reason to switch if you have a mandrel set-up that works good for you. I was frustrated applying my finish 3 or 4 times before I wouldn't sand through it. I haven't been turning any 7mm tubed pens or obviously a mandrel would have to be used or I'd have to get custom bushings for the centers.

 

[Proud_Poppa_of_2]

Originally posted by ozmandus

On bigger pens the bushings have an offset that is inserted inside the tube, but how do you handle the kits that have bushing that only butt up to the blank.. like the slimline..

Chuck -

JohnnyCNC makes and sells bushings for the 7mm pen kits (slims, Euros) so that you can turn those between centers. They fit inside the tubes just like the bushings for the larger pen kits do. You'll find information in this thread: http://www.penturners.org/forum/topic.asp?TOPIC_ID=29489

 

[Russianwolf]

As was mentioned Johnnycnc sell custom bushings thatfit inside the tubes on 7 mm pens as well as the more popular larger kits. Also, His bushings have a couple things that make the better than the stock larger kit bushings from the vendors.

1) tolerences are much tighter. When you slide the custom bushings into the tube, the first goes in perfect, when you put the second in the trapped air will push the first back out a bit. So there is no measurable play between his bushings and the tubes. When pulling them out, you will hear a pop like a cork coming out of a bottle.

2) the 60 degree milling. There is not a hole through the entire bushing since there is no need. The ends are milled to mate to standard 60 degree dead and live centers. So once you aligh the centers and put the bushing/tube in between everything is in alighment making it very true turning.

3) No hole through the center. another advantage to no hole through the center of the buhing is removing another place slop can happen. On the mandrel, you can have slop between the mandrel shaft and the bushing in addition to slop between the bushing and tube. The first is totally eliminated b the custom bushings, the later is effectively eliminated by the tight tolerences Johnny adheres to.

4) To me the custom bushings seem to be made of harder steel that the vendor bushings. meaning you'll have to replace them less often.

If your mandrel set-up is working great for you, keep at it. Once it starts fouling up, try some of Johnny's bushings. I'll bet you'll convert over happy once you try them. There's a reason he can't keep them in stock.

I can make 5 pen styles myself with his bushings now. Slimline, Modified Slimline, Comfort, Sierra, and Cigar. The Baron is next on my list, then I'll have to decide which kit I want to try after that.