Pin jaws ... or ... 25mm jaws???

[Dario]

I need to turn something that have a hole (30mm dia).

I already have a Talon chuck w/ standard #2 jaws...just wondering what my best option; pin jaws or 25mm jaws?

Am I better off buying a cheaper chuck system?

If anyone knows a good source for it please let me know too.

Thank you!

 

[Johnathan]

All of that stuff sounds like Chinese to me Dario! So I guess I can't help you.[]Jaws? Good luck.

 

[Dario]

Johnathan,

You are right, since chucks are not used much in pen turning.

It is a very nice tool to have for other turnings though. []

 

[smoky10]

Dario, I use the spigot jaws on my Talon for holding smaller turnings. They may be what you, want.

 

[Dario]

Okay, what will best serve this purpose...

I am working a deal to turn a few wheels (remember the lignum vitae thread?). Axis hole will be around 30mm and wheel is about 40mm wide. Outer wheel diameter varies from 4" to 8"

Another idea is turn the wheels first then drill the holes later...I am afraid I might not get it perfectly centered though so I am stearing away from this.

I am also planning on just making a wooden jam chuck if all else fails.

Any other ideas or preferences from listed choices above?

 

[johnson]

Are you looking to hold the part in the expansion mode? Does the hole go all the way through? If so, the pin may be the better one. It will grip further in on the blank. Could you use a jam chuck? It would be a lot cheaper. I would buy the jaws for the chuck you have, just because you know that chuck. I have heard that some of the cheap ones don't run true so you have to return them for a different one until you get a good one.

 

[Dario]

Johnson.

My plan for now is to use the jaws in expansion mode. Inside diameter is 30mm as mentioned so the jaws has to be 30mm or smaller. Yes, the hole will go through the 40mm thick wheel.

I forgot...I cannot use jaws with "teeth" outside, it has to be smooth so as not to damage the hole (very critical). The jaws also have to be straight outside (not tapered).

 

[johnson]

If the hole dia is 30mm dia x 30mm deep, make a jam chuck. Use the tail stock to support the turning until you are almost done, then back off the tail stock and clean up the area it touched. If you have changable tips in your tail stock, you can make a wood insert to push against the part you are turning so you don't leave any marks.

 

[johnson]

Here we go again, turn a cylinder with a shoulder that will seat against the jaws of your chuck. Make two cuts on the other end with saw of choice at 90 degrees to each other. Turn this cylinder down to the 30 mm dia long enough to go through the hole by about 1/2 inch. Chuck the cylinder against the shoulder of the jaws, mark the cylinder so you can chuck it in the same spot again. Put your blank on the jam chuck until you have the 1/2 inch sticking through and bring up your cone center on the tail stock. Tightening the cone center will spread the four quarters of the jam chuck out securing the blank. I wish I could remember where I read about this so I could give the proper credit.

 

[Dario]

Johnson,

I'll look into that more [].

My original plan was to make a 2 part jam chuck...almost identical for headstock and tailstock...only difference is that the headstock piece will have a bigger area where my #2 jaws can hold it.

Then the chuck jaws came in because it will be easier to clean the part nearest the hole. Not to mention that it will make mounting, reversing, etc the piece much easier.

Thank you.

 

[Dario]

Originally posted by johnson
<br />Here we go again, turn a cylinder with a shoulder that will seat against the jaws of your chuck. Make two cuts on the other end with saw of choice at 90 degrees to each other. Turn this cylinder down to the 30 mm dia long enough to go through the hole by about 1/2 inch. Chuck the cylinder against the shoulder of the jaws, mark the cylinder so you can chuck it in the same spot again. Put your blank on the jam chuck until you have the 1/2 inch sticking through and bring up your cone center on the tail stock. <b>Tightening the cone center will spread the four quarters of the jam chuck out securing the blank.</b> I wish I could remember where I read about this so I could give the proper credit.

Great idea!!! THANKS!!!

 

[Rifleman1776]

Are jaw sizes on chucks standardized? e.g. is the #2 on a Talon the same size as on a Oneway or PSI?

 

[Dario]

As far I know they are not interchangeable (though some are). Is it standard capacity/range wise? I think they are around that ballpark.

BTW, Talon is from Oneway.

 

[alamocdc]

Dario, Johnson has already given you two excellent ideas. The first in answering your question would be to use pin jaws. I believe you'd get a better hold using them than the 25mm (because of depth). The second was using the jam chuck he describes. Either of these would be more than adequate. A third idea would be to turn the wheels between centers and drill the hole last using a drill press. You should be able to hit center quite easliy, but if you are worried about it just build a 90 degree jig to hold the wheels for drilling and clamp it to the DP table so that it centers the hole.

 

[Rifleman1776]

Originally posted by alamocdc
<br />Dario, Johnson has already given you two excellent ideas. The first in answering your question would be to use pin jaws. I believe you'd get a better hold using them than the 25mm (because of depth). The second was using the jam chuck he describes. Either of these would be more than adequate. A third idea would be to turn the wheels between centers and drill the hole last using a drill press. You should be able to hit center quite easliy, but if you are worried about it just build a 90 degree jig to hold the wheels for drilling and clamp it to the DP table so that it centers the hole.

Good. Or: Leave some excess on the outside rim of the wheels and after drilling, put back on lathe and true wheels to round.

 

[dubdrvrkev]

Just to confuse the issue some more... First choice, pin jaws, I use them all the time. Second choice, jam chuck, I'd cut a taper on both pieces so it will be self centering. If you have a oneway live center the cone should work nicely and it would only be a one piece chuck. One other way might be to use your jacobs with a drum sander madrel, if that will expand enough it would save you from any marring of the wood in the hole.
Lots of good ideas in this thread, BTW sounds like a good excuse for a few new tools. [}]

 

[johnson]

Giving credit to where credit is due- The magazine article was in the AAW magazine, summer 2004 vol.19, no.2, page 46. The article is on turning napkin rings and is written by Jerry Hubschman. It has a drawing of the chuck he made. It is a cylinder 2" diameter, 6"long. There is a 1/2" hole bored in the end 3" deep with the cross cuts also 3" deep. There is a straight section the diameter needed to fit in your hole, and a curved cut behind that that dips down slightly below the straight section and sweeps back to the 2" diameter. Tightening your cone center spreads the four quadrants and holds the blank. I would add a shoulder to the 2" end for the jaws to seat against and mark it for remounting in the same place.