new Longworth chuck

[Jerry Allen]

This is the first time I've used my new Longworth chuck that I built.
Works good. (My Cole jaws will be up for sale soon.)
I have a Corel .cdr for one that will fit a Jet mini (about 10") if anyone with a laser wants it. I'll also post some details and a pdf for using a router or scroll saw. If anyone is interested just ask.

[Paul Heely]

The jaws look great. I would be interested in the details for making this with a route. Thanks.

[Colin MacDiarmid]

Me too, I would be interested in the pdf file, many thanks

[Ken George]

Just curious, what is the advantage of the Longworth chuck over Cole jaws? I have been using the Cole jaws for a couple of years now and except for the inconvenience of having to change the button positions for various sizes it has been very useful.

Thanks,

Ken

[Jerry Allen]

Just curious, what is the advantage of the Longworth chuck over Cole jaws? I have been using the Cole jaws for a couple of years now and except for the inconvenience of having to change the button positions for various sizes it has been very useful.

Thanks,

Ken

The inconvenience of having to change the buttons.
On this one you just loosen 6 wingnuts, adjust like a scroll chuck, Tighten the wingnuts, done...
Also the black buttons on my Cole used to leave black marks which were difficult or impossible to remove. This one does not.

[Jerry Allen]

Here's a quick .pdf.
Hope it's enough info.

[Jerry Allen]

Note:
I used a laser to cut out the ply. It's not real powerful (25W) and I can just get by cutting 3/8" ply. If I used a router, I might use 3/8 for the front and 1/2 for the back to add some stiffness. However, I have not had any problems with flatness or out of balance yet. When it's tightened up it's pretty solid and flat.

Regarding the nut:
It's got to be dead center. I drilled and taped the nut first and then aligned and marked it on the back plate using an old bolt I had as a guide. You could also turn a plug for the nut to align with a hole you drill in the rear plate. The hole then needs to be closed to provide a stop on the spindle when you mount the chuck.
Alternatively, instead of a nut, you could make a waste block, face plate, or similar, for the back plate to mount in a scroll chuck.

[Paul Heely]

Jerry, thanks for the PDF. I'll have to squirrel this away for the winter.

[Steve Schlumpf]

Great looking chuck Jerry! Thanks for posting the pdf file! Been thinking of making one to handle the bowls that are larger than what the Cole jaws will handle - this should help! Thanks again!

[Bill Stevener]

This old thread may be of some help. Tons of info. available for answers to questions can often be found by taking advantage of the search feature.

http://www.sawmillcreek.org/showthread.php?t=21578&highlight=%22longworth+chuck%22 Look on pg. 2

Hope this helps some.

[Jerry Allen]

It's also occured to me to make custom grippers instead of the leg tips to handle difficult holding tasks. Like special scroll sawed or routed shapes with silicone rubber sheet glued on the faces.

[Ralph Lindberg]

Excellent design, did you base this on the Woodturning Design article (Longworth Chuck Revisited) in the winter-2006 issue?

On my round-to-it list is the 6 pin Longworth chuck

[Bruce Shiverdecker]

Not to be crabby, but, How do you keep the feet aliged so that the piece is centered? Looks like they act independently, not in unison like a scroll chuck does.

Bruce

[Brett Baldwin]

Bruce, those curves in the plate keep the pads concentric. All the pads move at once to keep the circlularity even. Very cool design I think. Thanks for the file Jerry.

[Jerry Allen]

I updated the pdf file. There was a typo in the detail of the gripper saying 1/2 instead of 1/4. It did say 1/4 elsewhere.

Bruce, Brett is right. The curves oppose each other and the screw is traped in the diamond formed between them. You grab one of the circles at the outer diameter on each plate and as you turn, the grippers move in or out at the same diameter. Just like a scroll chuck.

Ralph, no, it was based on and article in Popular Woodworking or American Woodworker a few months back.

[Wally Wenzel]

Jerry, I made one of those a few years ago, and just a couple of weeks ago i made another. I turned the buttons for mine on my pen mandrel so i could shape them the way i wanted with more taper so as to grip better, then i diped them along with the head of the bolt in what is called plasti dip it is what they dip plier handles and the like in to give a cushion effect, i diped them 3 or 4 times to get a really good coating. It works as good as can be and is as fool proof as you can get. I use it all the time. I made mine out of 3/4 and 1/4 ply.
Wally

[Bill Stevener]

Just another good link, which may also be helpful.

http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=turning&file=articles_485.shtml

Check the other link I posted in this thread, look on pg. 2.

[Bruce Shiverdecker]

Thanks Bill. I missed that it consisted of TWO pieces.

Bruce

[Paul Heely]

Not to be crabby, but, How do you keep the feet aliged so that the piece is centered? Looks like they act independently, not in unison like a scroll chuck does.

Bruce

I would assume you could also help center it the same was as when using a a friction chuck. Use the tail stock and the center point on the foot of the piece that was left from earlier turning to center and hold the piece against the chuck until the feet are tightened.

[joe greiner]

Very well done, Jerry.

Some suggestions from my experience:
1. Cut some half-holes on the perimeter of the back disk. A Forstner bit works fine for half-holes. This enables rotating the front disk with one hand while holding the bowl with the other. (pic 1 - bowl absent)

2. Add a fender washer at the back disk to help the bolt stay perpendicular to the surfaces of the disks. Also, a snug retainer on the end of the bolt can avoid losing the wing nut when (not if) it gets too loose. A slot cut in the end of the bolt facilitates tightening the bolt for expansion mode, i.e. for an undercut rim. (pic 2 - washer was DIY HDPE; the retainer was micro-surgery on a wire nut.)

3. When tightening the bolts, work diametrically as for tightening lug nuts on a car wheel, vs. working around the circle. This helps to maintain a concentric condition on the compressed buttons.

4. A couple wraps of duct tape across the bowl to the back of the back disk is good insurance against a free-flying satellite. BTDT. Most finishes won't be harmed by brief contact with the tape adhesive.

Joe

[Jerry Allen]

Good tips, Joe and Wally

[DONNIE CRUMP]

i would like the pdf as well good job by the way

[John Keeton]

Donnie, this thread is four years old, and I doubt you will get a response. The .pdf file is posted in the thread and downloadable if you are a contributor. It probably is not viewable by you with a member status.

[Louis Prugh]

Jerry,
I would like the cdr file please.
Lou Prugh