| Bill's Very Adjustable Chuck |
The idea for this
chuck came to me while trying to shim one of the jaws on my Cole Chuck. I was
shimming to account for the slight out-of-round all turned pieces seem to be, prior
to finish turning the bottom.. This is especially true after leaving them lay
around for a while like I seem to do. So, I had the bright idea of making my gripper
buttons adjustable, cam-like, by mounting them off-center. The thru-bolt is
slightly over 1/4" off center, giving a range of adjustment of 1/2" or
more. You could even grip irregular shaped pieces by locating the grippers
into different sets of holes. As an example, a rectangular piece would be easy, by
having two grippers on the side(width) and two on the end(length). If you
needed a gripper in a specific place to hold that really irregular piece, drill a
hole where you need it !! |
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This "faceplate" is a piece of 3/4" MDF, about 10" in diameter. This technique could be employed to build any size chuck and with 4, 8, or 12 "grippers". Mounted on the chuck is a lovely Laurel Oak bowl made from one half of a crotch. I have an aluminum disc about 16" in diameter and a MDF disc 23" in diameter that are going to be "pressed into service" as Bill's "VAC"s when I get "a round touit". Inline skate wheels were $4 each, brand new. |
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Here you see a closeup of the "gripper". Notice that the bolt is off center. I turned the aluminum bushings on my Nova Comet, using a 1/4", very blunt scraper and sharpening frequently. They are a tight press fit and stepped to fit the wheel inside profile. I started with aluminum rod 1.125" in diameter. The bolts cannot turn within the bushings as they are pinned though from the side of the bushing closest to the bolt. A small wrench on the bolt head for leverage and tightening the wingnut on the rear side is all that it takes to adjust them. |
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I have not finished drilling all of the holes yet. I was in a rush to get the piece off of it that is in the first picture. The concentric circles are 1/2" apart for adjustment range and also aid in aligning the piece initially on the chuck. I put the tip of the tool rest near the base of the bowl to see how much the bowl is off center, and then tighten/loosen the correct grippers to re-center the bowl. I have 3 or 4 more holes to drill along this radial line. I laid out the four radials by using a framing square, through the disk center. |
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This shot shows one of the locking wingnuts on the back. I am using one of my 3" pipe flange faceplates. I might attach it to a good, flat 3" faceplate as the pipe flange is not quite flat nor true, on the front surface. |
| Things to do: * make larger versions using thicker MDF and also an aluminum plate version. * add router pad anti-skid material to MDF to increase the "gripability" at the bowl rim and to protect the bowl's rim. * make an additional set of grippers with much longer bolts so that I can add spacers under the grippers. This would allow thick rimmed bowls to be gripped. |
I had fun designing and making
this, especially turning the aluminum bushings. I think I've got about 3 hours total
in the project. Bill Brachhold Gainesville, FL If you want to e-mail me with more questions, feel free to do so: billbrach@hotmail.com |