Lathe Bowl Chuck




About: I am a high school student interested in metal and woodworking.

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.



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    7 Discussions


    4 months ago

    I'm afraid I'm going to have to weigh in with the other folks concerned about the safety of this project. Although conceived in the best of DIY tradition and beautifully executed, those metal bars, left long for adjustability, are likely to lacerate or possibly break, fingers.

    I once made a doughnut chuck similar to the one here on instructables. I thought my keenly honed situational awareness would protect me from the inch or so of threaded rod sticking out the back of the chuck, toward the headstock, 4 places. It didn't……


    5 months ago

    Put a disk of plywood behind the metal strapping. Cut some slots in the center for the bolts to pass through small enough that the straps hold the plywood down. put a second set of slots on the outside edge to hold the ends of the straps down. (slots, not holes, so that you can adjust the clamps with the 3-jaw chuck. narrow so that the bolting action holds the disk to the chuck)

    I think you are going to find that any pressure on the bowl is going to bend the straps and throw the bowl across the room. probably not with the size that you have chucked up, but using any of the other holes would be a problem.


    8 months ago

    This looks REALLY dangerous to me. Imagine that while turning a bowl and it comes loose. The first thing you are going to do, just out of reflex, is to grab for it. With four steel blades turning at high speed you could end up with bloody nubs where your fingers used to be.


    8 months ago

    I very STRONGLY suggest making arms of different lengths to accommodate different bowls. NOT a single set of arms that project from the lathe chuck, with holes for adjustment. If a piece of steel spinning at several hundred rpm hits a finger, it is likely to remove the finger(s) rather than just bumping the hand aside. There is a video on the web of a man whose sleeve was caught in the lathe. Not pretty. Safety first, please.

    2 replies

    Reply 8 months ago

    Thank you for your concern of safety towards my project. I understand and appreciate your concern for the chuck going at a high rpm. However, as stated above this is mainly for sanding and finishing the bottom of the bowl. Many people agree that the best rpm for sanding is 50-100 rpm. When I had the chuck spinning at the high end of that estimate (an rpm of 100) I still felt very safe and sure that I wouldn't get hurt from it. I also mention that you should sand the edges of the arms which will minimize risk even more. I acknowledge that this may not be the safest tool in my shop, but used responsibly (as with any other powertool) there should be very little risk of serious injury.

    Again thanks for your comment, I wouldn't want anyone to get hurt.


    Reply 8 months ago

    Good point. Don't trust that you'll remember they exist when they spin so fast you might not even see them! Something might happen on the lathe that could make you jump back by instinct, and off goes a finger!

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    8 months ago

    Interesting. I had never seen one of these used before. It looks really useful.