Another newbie chuck question...

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.

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

2. 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.

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

2. 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

Thanks for any advice!

================= 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.

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.

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