Correct way to tighten work in 1 hole scroll chuck?

[dontrinko]

I have a 3 jaw scroll chuck on a Craftsman 109. It only has one hole for a Tommy bar. My chucks for my Unimat have 2 holes and 2 Tommy bars.
What is the correct way to tighten the work in the jaws? I hesitate to use the pin that locks the lathe when using the back gears because if I do this i am tightening the chuck to the lathe every time I tighten work in the jaws.
For now I am using a strap wrench around the part of the chuck that does not have a hole for the Tommy bar. Thanks; Don

 

[francist]

If you drilled a small hole, say 3/16" or so, into the part of the chuck where you are currently using the strap wrench it would allow you to use a pin spanner. Not a quantum shift in methodology, but probably less fussy than a strap wrench every time.

-frank

 

[Wreck™Wreck]

What is a"one hole scroll chuck"?

Also what is a Tommy Bar? Please explain.

 

[chips&more]

What is a"one hole scroll chuck"?

Also what is a Tommy Bar? Please explain.

Some lathes just have a hole(s) in the chuck and in the spindle. And you put a round straight piece of metal in the holes and apply the needed force in that way. The round straight piece of metal has been called a “tommy bar”…Dave

 

[mikey]

Dontrinko, have you considered a new Sherline 2-1/2" chuck? They sell a 3 jaw and 4 jaw independent chuck with a 1/2-20 thread. Sherline chucks are quite good, well made and they have three tommy bar holes. They do rely on a hole in the spindle for a Tommy bar, though.

 

[chips&more]

I have a 3 jaw scroll chuck on a Craftsman 109. It only has one hole for a Tommy bar. My chucks for my Unimat have 2 holes and 2 Tommy bars.
What is the correct way to tighten the work in the jaws? I hesitate to use the pin that locks the lathe when using the back gears because if I do this i am tightening the chuck to the lathe every time I tighten work in the jaws.
For now I am using a strap wrench around the part of the chuck that does not have a hole for the Tommy bar. Thanks; Don

Does the chuck have a backplate? Can you put a hole(s) in the backplate? The backplate could also be the knurled part. And I do not see a problem in adding a hole(s) in that area…Dave.

 

[Wreck™Wreck]

Some lathes just have a hole(s) in the chuck and in the spindle. And you put a round straight piece of metal in the holes and apply the needed force in that way. The round straight piece of metal has been called a “tommy bar”…Dave

I suspect that the holes are for installing or removing a chuck on a threaded spindle?

 

[4GSR]

Here's a picture of the chuck Don is talking about. The only difference is my chuck has 3 holes spaced evenly around the perimeter of the chuck. Instead of one hole. And yes, the rear hole can be used to remove the chuck from the spindle.
Ken

Correction! The front holes are used to remove the chuck. The rear holes operate the scroll in the chuck. Sorry.

 

[dontrinko]

mmine has 3 holes in the knureled ring but no holes in the front part that holds the jaws.

 

[4GSR]

mmine has 3 holes in the knureled ring but no holes in the front part that holds the jaws.

Don,

There's a very good chance, the holes were put in the chuck body by my dad when he bought the chuck many years ago. Ken