Don Pencil Jam Chuck

[cwearing]

Anyone have experience with this product?

 

[Mark Wollschlager]

I have one and have used it a couple of times.
I have turned a couple of cones with different tapers.
A bit more DIY than a kirsten kone, but the same result in the end.

mark

 

[William Hutchinson]

It's a handy tool to have around for those hard to hold forms. The holding friction is between the tailstock and end of the jam. The cone is used to center the piece with only minimal pressure, (DAMHIKT).

 

[Odie]

Just took a look at this jam chuck on the DP site......and, it's a little confusing as to how it works.

Anyone care to explain it for us dummies?

thanks

ooc

 

[hockenbery]

Odie,

Assuming this is like other reverse chucks I have seen,

It looks like a hollow from turned with a faceplate and a wooden cone of similar color.
Gives the illusion of a wide lipped vase shaped opening on the top of the hollow form hollow form.

The rod sticking out of the head stock has a morse taper on one end and a soft pad or cup on the other end.
The hollow form is put over the rod with the soft pad resting on the center of the bottom
The tailstock is brought up and when tightened it centers. The Pressure from the tailstock goes through solid wood to the pad on the end of the rod.
Pressure can't break the hollow form.

On the left is a wooden cone with a hole in the center the diameter of the shaft. The cone is slid into the opening of the hollow form and a locking collar on rod holds it in place. The cone is just to keep the hollow form from vibrating there is no pressure on the opening.

On the right is the faceplate tenon that needs to be tune way to finish the bottom.

Hope that is somewhat clear.

Al

 

[hockenbery]

odie

here is a crude picture

the red is meant to be the wall thickness.
black is the pad and gray the shaft of the rod indside the form

my little pictures don't line up quite right.

 

[Odie]

Odie,

Assuming this is like other reverse chucks I have seen,

It looks like a hollow from turned with a faceplate and a wooden cone of similar color.
Gives the illusion of a wide lipped vase shaped opening on the top of the hollow form hollow form.

The rod sticking out of the head stock has a morse taper on one end and a soft pad or cup on the other end.
The hollow form is put over the rod with the soft pad resting on the center of the bottom
The tailstock is brought up and when tightened it centers. The Pressure from the tailstock goes through solid wood to the pad on the end of the rod.
Pressure can't break the hollow form.

On the left is a wooden cone with a hole in the center the diameter of the shaft. The cone is slid into the opening of the hollow form and a locking collar on rod holds it in place. The cone is just to keep the hollow form from vibrating there is no pressure on the opening.

On the right is the faceplate tenon that needs to be tune way to finish the bottom.

Hope that is somewhat clear.

Al

OK, thanks Al..........I think that clears it up for me. Makes sense to me now. What confused me is I had been thinking the "cone" used to stabilize the lip of the hollow form opening was part of the turning.....threw me off there!

Also appreciate your effort to make up a visual reference.......:cool2:

ooc

 

[Carole Valentine]

Suggestion

Cut some white rubber shelf lining material and put it on your turned jam chuck. Greatly increases the drive friction.