I have an old Craftsman lathe that one of my neighbors left out on the curb.
He (or she) also left the tools that came with it. After sharpening the
tools, I found the lathe works just fine, and I'm having fun with it.

I got a 4 jaw chuck very cheap on ebay, along with some new ( much needed
M2) centers. The chuck is an older one, and the jaws move independently!?

So the question... is there an easy way to center work piece in the jaws?

I thought perhaps I could turn one round piece with a small centered round
section to fit in the center screw hole (to find the first center), and then
additional rings to fit on that... to help me get the jaws at least close to
center somewhere near the diameter of the part I want to hold (does anyone
get what I'm trying to say?).

Thanks for any advice!

Steve

I get you :-(

With independent jaws, there is really no easy way to center the jaws
(that's why the self centering is called that way).

I'm not an expert but it seems that measuring the spaces between the
jaws (with something accurate) will give you an approximate estimate
(if the distances are the same between all jaws - then they are each at
the same distance from the center i.e. centered)

I'll say it again, I'm far from the expert and I hope I'm not
misleading you.

You should know that there are some neat uses for your type of chuck,
such as mounting irregular pieces and such.

All the best
Moshe

Hi Steve

A 4 jaw independent chuck can be usefull to turn off-center pieces. You
can also turn regular round pieces but the biggest draw back I found
was that if the piece ever slips out or if you ever want to chuck up
the work again for whatever reason, it can be a nightmare getting the
jaws back to the original position. I even went and bought a run-out
gauge and magnetic base but it was still a nightmare. I also found that
the jaws themselves do not have the grip you get from a Oneway or Nova
etc.

As Moshe says though, there are still interesting uses for that type of
chuck so don't throw it out. Do keep your eyes open for a good
self-centering chuck though.

Mike

Hello Steve,

What you propose should work if you also use the tailcenter to align the piece
that fits into the center hole of the chuck. A much simpler method would be as
follows:

1. Place the tool rest across the face of the chuck.

2. Bring up the tail center and make a center of rotation mark on the tool rest.

3. Make a mark on the operator's side of the center mark that is exactly 1/2 of
the diameter of the piece you want to hold.

4. Position a first jaw in alignment with the tool rest and adjust the jaw to
align with the mark.

5. Repeat step 4 for all of the other jaws. At this point, your chuck jaws
should be very near to perfect alignment and very close to the diameter of the
workpiece.

These chucks are less than superior for holding wood since they were designed to
hold metal. They can be made to work however as the old timers used them all of
the time. They did work better to hold the extremely hard woods like boxwood or
for holding ivory.

Fred Holder
http://www.fholder.com

In article , Steve says...

I have an old Craftsman lathe that one of my neighbors left out on the curb.
He (or she) also left the tools that came with it. After sharpening the
tools, I found the lathe works just fine, and I'm having fun with it.

I got a 4 jaw chuck very cheap on ebay, along with some new ( much needed
M2) centers. The chuck is an older one, and the jaws move independently!?

So the question... is there an easy way to center work piece in the jaws?

I thought perhaps I could turn one round piece with a small centered round
section to fit in the center screw hole (to find the first center), and then
additional rings to fit on that... to help me get the jaws at least close to
center somewhere near the diameter of the part I want to hold (does anyone
get what I'm trying to say?).



Thanks for any advice!

Steve

"Steve" wrote in message
...
I have an old Craftsman lathe that one of my neighbors left out on the
curb. He (or she) also left the tools that came with it. After sharpening
the tools, I found the lathe works just fine, and I'm having fun with it.

I got a 4 jaw chuck very cheap on ebay, along with some new ( much needed
M2) centers. The chuck is an older one, and the jaws move independently!?

So the question... is there an easy way to center work piece in the jaws?

I thought perhaps I could turn one round piece with a small centered round
section to fit in the center screw hole (to find the first center), and
then additional rings to fit on that... to help me get the jaws at least
close to center somewhere near the diameter of the part I want to hold
(does anyone get what I'm trying to say?).

Thanks for any advice!

Steve
=================
Steve,
Since you say you have "centers", I'm assuming you mean some sort of drive
center. If that's the case, start off between centers and turn a tenon on
the headstock end. This shouold be long enough for a 1/2 inch or more from
the chuck. then center the piece as well as you can by eye, rotating it by
hand. Then start the lathe at it's slowest speed. Using a sharp pencil,
SLOWLY bring the pencil up near the tenon until it barely makes contact.
Turn off the lathe. Locate the pencil mark. That will be the high point on
your tenon. Loosen the jaws opposite the mark and tighten the jaws on the
pencil mark side Repeat until you have it as centered as you want. However,
if you remove the piece, you will have a VERY difficult time recentering.
It's slow, but it will work.

Ken Moon
Webberville, TX.

"Steve" writes:

I got a 4 jaw chuck very cheap on ebay, along with some new ( much needed
M2) centers. The chuck is an older one, and the jaws move independently!?

So the question... is there an easy way to center work piece in the jaws?

In metalworking, they use dial indicators to make sure the jaws are centered.
You can get one with a magnetic base for $15 at Harbor Freight.


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Steve, I took a quick look at the ng before taking off to the symposium
this morning, so no time to explain. An off center blank held between
your four jaw chuck (aka invention of the devil) and a tail center will
scribe a circle on the tail end until it's centered. How about using a
wiggler center finder? Somebody explain or more likely refute. They
are cheap, but a cobbled up version could be made for woodturning. If
work isn't supported by the tail center, centering in the chuck by
eyeball should be good enough, though risky for fingers and flying
blanks.


Turn to Safety, Arch
Fortiter



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