Shafts between centers

Dec 01, 2004 7 Replies

Hi folks, I'm not a turner, but a friend wants me to make some shafts for him. They have to be turned between centers as part has to be ground later. Material is mild steel, all shafts have a large end & a small end. Large end about 3/4", & 3"long, small end (the one to be ground) 5/8" longest one 8", others a bit shorter. I plan to cut the material to length & center drill both ends, but if I use a drive dog, how do I machine where the dog is? If I start with a longer shaft & part off the stub where the dog was I can't drill a center exactly on center. My idea is to cut to length, center drill, machine 5/8" diameter (leaving 5 thou. for grinding) & machine as much as I can of the large end, leaving about 10 thou. to go, & then removing the dog & hope that I can get enough drive from the center to bring the part not yet machined down to the 10 thou. too big size & finish with a light cut to size. Please help with a better (correct) way of doing this.



T.I.A. Ian sutherland. Oz.


zsutherland snipped-for-privacy@yahoo.com (Ian Sutherland) wrote in news: snipped-for-privacy@posting.google.com:

Why can you not get a center back on center after parting off the drive dog area? You need to leave about 0.01" on the area to be ground anyway (grind stock) leave it long enough for the dog, part off, turn it around, indicate it back in and center drill the end.

Rx:

Saw cut. Chuck, face, and center drill 2 pls. Change to centers, live or greased dead center, drive dog and drive plate. Poisonous white lead is good on a dead center.

Drive stock and turn 3/4. Flip stock and add a copper penny or pad under dog screw. Drive stock and turn 5/8. Done. (I think)

The thing about the centers is you can take the part in and out as many times as you want and it always sets up in the same position reliably, unless you catch a chip.

I tolerance everything and tolerate everyone. I love: Dona, Jeff, Kim, Kimmie, Mom, Neelix, Tasha, and Teri, alphabetically. I drive: A double-step Thunderbolt with 657% range. I fight terrorism by: Using less gasoline.

Do they still make spur centers?

Jim

from the lathe dog you would still have a hole for your center?

Parting off between centers? Are you crazy? You _never_ part off between centers! Phil

parting off the part

center?

Hi guys, thanks for the reply's, I knew there had to be a way to do this, just didn't think of the obvious, of course the above poster is correct, just flip it after one end is done particularly if I do the small end first, any mark from the penny will disappear with the grinding. Thanks for a great group. (I read the posts every day.) Cheers, Ian Sutherland.

Thanks, now I know what to do with all those extra pennies. I'm just about out of alluminum shims i use under the chuck jaws.

John

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