Longworth Chuck Question

Gord Rock

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619
Location
Red Deer, Alberta, Canada
I'm thinking of building a Longworth Chuck to reverse bowls to finish their bottoms. My lathe has a 12" swing. What is the largest bowl I can mount on a Longworth Chuck if I make it the maximum size for my lathe? :huh:
I realize there are likely a number of variables based on exactly how I build the Chuck. I have a bowl with a 9-1/4" outside diameter that I'd like to mount in it. Is that bowl too large? Anyone with experience using a Longworth Chuck, I'd very much appreciate your feedback. :) :wave: :thumb:
Thanks,
.....Gord
 
Gord, if the curved slots go close to the edges of the chuck, and if your rubber 'buttons' are small enough, I think you might just squeeze by, but it'll be very close.

Let's see...

Chuck diameter = 11 7/8"
Slots to within 1/2" of edge = effective diameter of 10 7/8"
Account for 1/2" button diameter = effective diameter of 10 3/8"
 
Gord, if the curved slots go close to the edges of the chuck, and if your rubber 'buttons' are small enough, I think you might just squeeze by, but it'll be very close.

Let's see...

Chuck diameter = 11 7/8"
Slots to within 1/2" of edge = effective diameter of 10 7/8"
Account for 1/2" button diameter = effective diameter of 10 3/8"

Wow, a math major!! :thumb:
Thanks, Vaughn, I'm going to give it a try if I have time this weekend and see what happens.
Thanks again,
.....Gord :wave:
 
Math major? Me? :rofl: My freshman college algebra professor suggested I drop out of his class before he had to flunk me. :p

Even if the Longworth chuck ends up not fitting the bowl in question, it should be handy down the road for other pieces. :thumb:
 
Gord, always remember dependant on the actual form of your bowl/buttons you can locate it in expansion mode as well with the buttons on the inner surface, even if it does not actually grip, it can be used to align the piece and use the tailstock and revolving centre to hold it in place.
 
longworth chuck question

They all beat me to it ,but I made one and it holds a 10" bowl,but I got those little rubber pads right on the edge.Works pretty good.I have the holes drilled in 1/2" increments to take many different sizes.
 
They all beat me to it ,but I made one and it holds a 10" bowl,but I got those little rubber pads right on the edge.Works pretty good.I have the holes drilled in 1/2" increments to take many different sizes.

Ken, sounds like you're describing Cole Jaws, the ones that attach to your regular chuck and have lots of holes so you can hold different sizes of bowls. Longworth chucks has slotted holes (usually 4, 6 or 8) that are cut in a spiral to make the little rubber pads infinitely adjustable.

Cole Jaws:

nova%20cole%20jaws.jpeg


Longworth Chuck:

2084d1200266325-longworth-chuck-long-open_edited.jpg
 
Hey...a pic of my first Longworth chuck surfaced on the web! How cool is that. I made that about 2 years ago. You can figure loosing 2". So a 12" will net a bowl about 10"....Bill...
 
Bill,

That was your *first*??? Pretty cool. That would be like my third! ;)

My first is sitting in unassembled pieces behind my lathe. I did something silly, it's been a while, so I forget what it was exactly. But whatever it was, the project crashed and burned... ;)

Thanks,

Bill
 
I made one a while back, but turned out it was too small to really be of use now.. I made it for use on my Jet1014 and I've since then bought a set of Cole Jaws for my PSI chuck... it's laying on the work bench under a pile of other things I don't use.
Mine didn't look as good as the one shown here though.
 
Hey...a pic of my first Longworth chuck surfaced on the web! How cool is that. I made that about 2 years ago. You can figure loosing 2". So a 12" will net a bowl about 10"....Bill...

I found the picture doing a Google image search. It was the best one I saw. I should have looked to see whose it was so I could give due credit. :D

Is there something about the Longworth chuck that will keep it from unscrewing if he puts his lathe in reverse?

On the one I made, the rubber bumpers were held in place with bolts and wingnuts. Once they're all tightened down, they seemed to stay in place.

Left loose, the chuck will have a tendency to open when the lathe is turning in one direction and close when it's turning in the other. Which way it goes depends on whether you curve the slots to the left or the right. Either way, it can work to your advantage or disadvantage, depending on if you're chucking the inside or the outside of the rim.
 
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