|Project by Jim Jakosh||posted 07-18-2012 02:11 PM||6961 views||58 times favorited||34 comments|
I have read a lot about the Longworth chuck and thought I might need one some day so I built this one out of Corian with spanner wrenches made of maple, walnut and brass. The instruction for building one seemed to be the most complete in the following link:
I use two pieces of 1/2” corian and took the drawing and the material to LJ tyskkvinna (Lis) at the Geek Group in Grand Rapids. They have a CNC router and I figured that would be the best way to get the slots perfect. She had the plates cut for me with a center hole, slots and grab holes around the perimeter.
I turned a center hub out of steel with a 1”-8 thread and put in 8 1/4-20 bolts that are threaded into the Corian.
I counter bored one the the plates in the center to add a brass washer to hold the plates together during assembly. I used #6 bottle stoppers from a hardware store in Indiana with 1/4- 20 bolts in the center. Each stopper has a sleeve in to adapt it from the 3/8” center holes to 1/4”. I use lock nuts on the back but it turns quite hard to adjust the size with them so I probably will change to threaded knobs like all the other chucks are shown with.
Under the stopper I have Lexan washers for the part to sit on but I think they will need to be a bigger diameter. I will also try it without them.
The chuck is 10 1/4” diameter and has a capacity of 3 3/8” to 7 1/2”. I have a drawing for 6 extenders to mount on it to increase the capacity without having to make another chuck. I tried to show it with a bowl I have by the lathe but it is 8” and would not fit.
The last shot shows it running in the lathe to show that the Corian will not just fly apart like I had been told when I was making it.
-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!