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.

(Ian Sutherland) wrote in
om:

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.



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.


--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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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.

In article , Ian Sutherland
says...

Please help with a better (correct) way of doing this.

Do they still make spur centers?

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Ian Sutherland
says...

Please help with a better (correct) way of doing this.

Do they still make spur centers?

Jim

Could you drill a deep center hole and then after parting off the part
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


Ian Sutherland
says...

Please help with a better (correct) way of doing this.

Do they still make spur centers?

Jim

Could you drill a deep center hole and then after
parting off the part
from the lathe dog you would still have a hole for your
center?
--
==================================================

( Doug Goncz ) wrote in message ...
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.


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.

Doug Goncz wrote:

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.



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