I like turning bowls but had trouble sanding and finishing the bottoms of them while the bowls are mounted on my lathe. After doing some research I found that my lathe chuck had an attachment for this but didn't want to spend the money on it. After thinking of it for a while I came up with a cheap and quick way to solve my problem
Step 1: Supplies
You will need four rectangular pieces of steel for each arm, a rubber gasket or rubber bands to wrap around the screw heads for extra grip and screws and nuts so you can adjust the size of each arm. I found two pieces of galvanized steel in my scrap bin and decided to cut four arms from them.
Step 2: Measuring Your Lathe
My lathe was about six inches from the middle of the chuck to the bed of the lathe. I decided to cut the arms to 4.5 inches to allow ample clearance for the arms. My chuck also is able to be tightened and loosened a little over 3/4 of and inch.
Step 3: Cutting the Arms
From the measurements I cut out four arms each 4 1/2 inches long by 1/2 inch. I used tin snips for the first cut and a hacksaw for the longer cuts. I cleaned up the cut marks using sandpaper.
Step 4: Drilling Holes in the Arms
After cleaning the cuts I taped all the pieces together to allow me to drill all the holes at one time. I traced a jaw on from my chuck to find the hole spacing. I measured out four holes 3/4 inches from each other from the other side because of my chuck allowance. I used a metal punch to mark the center of each hole. I then used a drill press to drill each holes. For the outside holes I used a 3/16 bit and for the chuck holes I used a 1/4 inch bit.
Step 5: Finishing the Arms
To finish up the arms I beveled the two largest holes on the chuck. I then sanded each arm using a belt sander to clean up the overhang from the drill press and to remove sharp edges. I also rounded each corner to make them less sharp.
Step 6: Attaching the Arms and Rubber Gaskets and Screws
I used the screws that came with the chuck to attack the arms. I then threaded a rubber gasket onto each screw and attach one to each arm.
Step 7: Attaching to the Lathe
After I was sure that everything was tight I attached the chuck to my lathe. This chuck is very easy to use and is safe for wooden bowls since the rubber wont dent or mark the bowl. For an example I attached a wooden bowl i already made. It held the bowl very securely and made it easy to sand. This project saved me a lot of money since all the supplies were found around my workshop.
Step 8: An Example of the Bowl on the Lathe.
CAUTION: Be very careful when using this chuck. Screws could become loose when it is spinning and your bowl could fall off. Also keep your hands away from the swinging arms because it would be very easy to get smacked by it.
Thanks for looking at my instructable! I hope it helps with your wood turning needs.