Sphere Re-Turned Off Center ???

[Bob Salvetti]

Now that I have a truly round wood ball, I would like to remount it on the lathe to cut some decorative grooves partially around. How can I hold this off center ?

 

[Mike Peace]

Between somewhat sloppy friction chucks, turning somewhat green wood, and not getting the sphere perfectly round, some of my decorative grooves generally disappear part of the way around some of the time. Close enough for me. You might try accenting the grooves with paginating wax. White on dark wood or brown on lighter wood. Or use heavily spalted wood and skip the grooves.

 

[hockenbery]

You can use an off center drive cup.

I learned this from Christian Burchard. Turn a wooden cup drive on a 3" faceplate.
Loosen one screw, remove the others. Turn the cup on the loose screw. Put the screws back in.
Make sure the diameter of the cup is 1/3 the diameter of the ball.
You now have an off center drive cup. One side of the ball will come closer to tool rest.
Turning an rotating the ball you can cut arcs.

On the tailstock side you need a flat surface about a 1/2 inch in diameter. To push the ball into to the off center cup.
I make these from wood and cover the contact area with a small pied of leather.

This is relatively safe if you know what you are doing. I had someone teach me.
An 8 inch ball pulled out of the cup could cause grievous injury.
A three inch ball is baseball size. People get killed by thrown baseballs every year.

Be safe,
Al

 

[Dale Miner]

Al,

I have done something similar by taking two jaws off the chuck, using a square block in the chuck, and turning the cup in the part of the block projecting from the jaws. To get the offset after turning the cup. loosen the chuck and slide the block sideways in the two jaws and retighten the chuck. I used #3 profiled jaws when doing it.

Yes, use a large cup, and keep the rpm's down.

Was Christian Buchard the orginator of this? Seems like he was.

 

[Joe Greiner]

If you used cup centers to make it truly round, put a couple layers of masking tape on the same side of each cup. Or you could borrow my cup centers.

 

[Bob Salvetti]

Grooves in Spheres

Many thanks !!

I'll try the off-center drive and flat tail center.
My poor old brain was missing the flat tail piece.

 

[hockenbery]

Dale,
thanks for your tip. I turn an ornament from a 1x3x8. Where I hold one end in two jaws so I can make a hole in the 3 inch face and inch from one end. Never thought about sliding to the other side and making a hole on that end. The wheels are spinning!!!

Chuck will give sort o infinite adjustmen

With the screw you have to move a least a screw hole off center.
One advantage ? Of the faceplate is you can repeat the same offset easily
Guess you could put a pencil line on the Wood to mark how far to slide.


Thanks
Al

 

[Timothy Rowe]

Bob

Bob you are off center anyways just rechuck it regular it will already be off center. Your dear friend Tim LOl

 

[Thomas Stegall]

Or turn a chuck like David Sprigett uses for his chinese balls, then mount off center on a faceplate and you will have no chance of it flying off.

 

[Bob Salvetti]

Off Center Presidents

Hey Mr. Rowe,

Nice to see that you remember me and how well (?) I turn.
Sorry I wasn't there to vote for you - again, and again, and again.

I went to the restroom at one of our meetings and now I'm the Vice President of the Bi-City Woodturners guild.

Hope all is well with you and all the "guys".

 

[Timothy Rowe]

Florida Symposium

Lee and I are demonstrating at the Florida Symposium this weekend if you are coming down you can see how crazy crackers turn again::cool2: