Stilll More on Simple Sphere Turning Aid

Thanks, Dennis

GaryG in MD

It was a pleasure to work with you. ...GG

Re: Stilll More on Simple Sphere Turning Aid

Craig Daymon

Question, do you still bring the sphere to final form between 2 cup centers and work away any shadows, or is it just a matter of sanding away a little nub of the final tenon?

I recently created a few spheres using cup centers I made from UHMW plastic. They worked well for the Osage Orange sphere, but did leave some (slight) marks on the burl spheres. I've recently purchased a 2" diameter cylinder of 80A hardness polyurethane that I'm going to make new cup centers from, which should be much less marring, except maybe in some of the softest woods. (The 80A hardness was based on inline skate wheels, which range from something like 70A hardness to just over 100A. Bought the cylinder from McMaster-Carr.)

I saw Dave Hardy demo sphere turning years ago using your technique, though I think he still finished between cup centers. He was a very skilled turner and could get it close enough to true that there was little more than some light sanding to be done between cup centers.

I understand the principle. It is much the same as using trapezoids to perform numerical integration on a computer.

What a newsletter!

John K Jordan

My stars, that's got to be the most complete, informative, and interesting woodturning newsletter I've ever seen!

JKJ

Re: What a newsletter!

philip f Duffy

Amen to that! P.

Re: What a newsletter!

RCH

Remarkable newsletter! It's abundantly clear why you won the "Best Newsletter" award!

Re: Stilll More on Simple Sphere Turning Aid

Dennis in Southern Oregon

Craig, I have tried the cup center approach a few times. It is probably just me, but I seem to have trouble getting the cup centers to center reliably. I seem to need to start with a sphere to get a sphere! I thought of a couple of approaches to try; if they help, I will get back.

thanks guys

GaryG in MD

That's nice to hear.

I'll pass this link on to our Editor, Bill Long.

I'm working on my deliverables for the July issue right now!

That calendar just won't hold still, and it's a real slave driver!

Will somebody please tell me how 2016 can be half over already?

Seems like it just started! ...GG

Re: Stilll More on Simple Sphere Turning Aid

Doug Wolf

Craig,

Quote:"I recently created a few spheres using cup centers I made from UHMW plastic. They worked well for the Osage Orange sphere, but did leave some (slight) marks on the burl spheres. I've recently purchased a 2" diameter cylinder of 80A hardness polyurethane that I'm going to make new cup centers from, which should be much less marring, except maybe in some of the softest woods."

I put a layer of masking tape over the cup centers and it seems to eliminate the marks. Also it add a little bit of friction to prevent slipping. It doesn't seem to be a problem with any movement of the sphere when turning the high spots off.

holding between centers

John K Jordan

I've had good luck with very thin pieces of closed cell foam. No marks, grip well. For smaller diameters I either cut a donut or cut out clearance wedges around the circumference.

Lately, I've been using the Rubber Chucky mandrels and their soft plastic drive chuckys turned with a concave face to fit spheres. I see they now sell Anything and Sphere chuckys which might save making them.

(I really like the products but a word to the wise: they sent me several bad MT2 mandrels. If you buy one, see if it wiggles with excessive play in the headstock taper. He told me to pound them in with a hammer since all MT tapers needed to be "seated" but I chose to re-machine them correctly instead.)

JKJ