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I am presently using a Nova midi chuck on my jet 1220, i was looking at the Nova Cole jaws and have a question. Could you make your own? I realize that the factory made ones are probably balanced. But I am curious about what others may have done. I am going to list a want ad for a set of the cole jaws anyway. Thanks in advance!
Paul Ashman
......bartender, I'll have what the gentleman on the floor is having.
I made up my own set out of some plywood. Balanced or not, they worked pretty well for my liking.
See pics:
http://sacramentoareawoodworkers.com...s.php?album=19
I had a set of home-built (http://www.sawmillcreek.org/showthread.php?t=33724), but I got a "factory" set free when I got the Barracuda chuck from PSI: they're now permanently installed on my older PSI chuck.
Paul, i have a set of the jaws from oneway, don't remember the name , they work ok but require a lot of changing around to use. I made a Longworth chuck and like it much better, all you have to do is thread it on the spindle and go and they are not that hard to make either,just google longworth chuck for all kinds of info. Wally
Paul,
Another option is a Longworth chuck:
http://www.fholder.com/Woodturning/chuck.htm I haven't made one, but it looks really ingenious.
Here is an article covering a bunch of options:
http://www.cumberlandwoodturners.com...ng%20Bowls.pdf
Wes
Thanks for all of the replies, I am going to make a set of jaws first, then tackle a Longworth!
Paul Ashman
thats the way the world goes round, one day you're up, the next you're
down. J. Prine
I have the cole jaws for my Nova SN2s. They won't fit some bowls that are sized between the min and max of the jaws. One hole is too small, and the next hole is too big. I talked to Tim Geist about it, and he said if I'd send him the jaws, he'd drill and tap out the places between the holes. (if you turn it over, you can see the spots for extra holes between the threaded holes) He said there is room to drill and tap them between the other holes. I just told him that I would do it. I haven't yet... but I still plan to. I made two of the Longworth Chucks. Made the inboard size first, then decided I should have made it to fit the outboard. (duh! should have thought of that first).
I really like the Longworth... It works on all bowls larger than 4.5 inches.
Have also made a couple of Longworths for 12" and 16" lathes. Despite what I thought was careful workmanship mine don't center perfectly, but are close enough to clean up the foot of a bowl. They grip inside or outside, and have used them mostly to flatten (turn and sand) side one of segmented rings to ~15-3/4" dia. Best to start with a "dedicated" faceplate and leave it permanently mounted to the Longworth (or vice versa).
I bypassed the Cole jaws and went directly to the Longworth. I made two of them.
The first swings 1/8in shy of the bed, and mounts on my Griz H6265. I cut 4 dovetail slots in the back of the back disk to engage the jaws of the Griz, with the jaws flush with the Griz body for minimum diameter, and "bridges" between the slots to secure the center pivot. The Griz chuck reaches far enough toward the bed to clear the motor. (Half-arze location copied from other such by our friends in the Peoples' Republic)
For the second one, the disks are small enough to clear the motor. To get the smallest possible diameter, I epoxied a hex nut into the back of the back disk.
For both of these, I used 6 buttons, because it's easier to lay out a hexagon than a square or octagon. Also, I put holes in the front disk and half holes on the rim of the back disk. With this arrangement, I can adjust the diameter with one hand while holding the bowl with the other, sometimes with tailstock assist.
As to eccentricity: The button bolts need to be slightly loose to enable diameter adjustment. I tighten them once the bowl is secured. Tightening sequence seems to be critical. If tightened in circular sequence, eccentricity goes bonkers, because compression of the rubber buttons changes their diameter. Better to work diametrically across, similar to tightening lug nuts on a car wheel.
I previously used a piece of plywood on a faceplate, with a groove turned to mate with the bowl edge, and duct tape or filament tape wrapped around the bowl to the back of the plywood. The disadvantage of this is that there's no adjustment, and a new groove typically needs to be turned for each bowl. Even so, for very thin walls, the Longworth puts too much localized stress on the bowl rim, with undesirable results (shall we say); so I still use the faceplate-and-plywood method for those.
The buttons provide a tenuous purchase on the bowl rim (same with Cole jaws, I believe). So I still use tape for added security, just not as much of it. And for all of these, light cuts are the order of the day.
Joe