Segmented Bowl Clamping Jig

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Blog entry by lew posted 07-03-2013 05:11 PM 3802 reads 2 times favorited 28 comments Add to Favorites Watch

After turning a bowl recently from a solid chunk of log, I thought it might be interesting to try my hand at a segmented bowl. After researching the procedures, I figured I better start with a clamping system to glue the stacked rings. There are a wide variety of clamping devices listed on the various turning sites but they are all discrete units. In my little shop, there just is not any more room for an additional piece. I am at the point where when something comes in- something else has to go!
Therefore, the problem became, how to make a sturdy, stable clamping device that at the same time would be easy to disassemble and store. A couple of trips to Lowes; rummaging through the salvaged hardware box and some scrap 2×4’s yielded the following bowl clamp.

2×4’s, set on edge, create the top frame of the clamp.

The top of the workbench forms the clamp base. Holes through the top frame, aligned with the workbench dog holes provide the connection points for 5/8” all-thread.

Glue, screws, and lag bolts secure the top frame sections together.

A piece of 1” all-thread applies pressure to the segment rings. A captured nut holds the all-thread in the top frame. The nut is inserted/epoxied into a recess in the top frame.

A built up plate applies the actual clamping pressure. The plate swivels on the all-thread. Two stop nuts, one reversed, capture the pressure plate on the all-thread leaving just enough clearance for swiveling. Recessing the bottom nut prevents it from contacting the segments.

I needed a method of cranking down the pressure. I had an old bandsaw tensioning device with stripped threads- just repurpose the crank. I re-drilled the crank hole to ½” and ground the 1” all-thread to fit. Tighten the allen set screw and we are in business!!

The finished system-

A little completely unscientific test indicates some pretty good pressure-

The dimensions of the clamp were arbitrary and pretty much set by the materials available. As built, the maximum height is approximately 13” and an adjustment range of about 3.5”. The 5/8” all-thread nuts lower the unit for smaller dimensions.
I think my first project will be a mortar for the pestle shown lying on the bench. The pestle was a flea market gift from a friend. If the mortar turns out, I will present him with them both, as a set.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

28 comments so far

View Drew - Rock-n H Woodshop's profile

Drew - Rock-n H Woodshop

644 posts in 2686 days

#1 posted 07-03-2013 05:17 PM

This is what’s called “thinking out of the box”. Great thinking and 200 lbs of pressure is awesome. Good enough to keep glue and pieces in place.

Good job!


-- Drew -- "I cut it twice and it's still too short!"- Rock-n H Woodshop - Moore, OK

View SPalm's profile


5320 posts in 3877 days

#2 posted 07-03-2013 06:50 PM

That is down right clever.
Good idea.


-- -- I'm no rocket surgeon

View CalgaryGeoff's profile


937 posts in 2477 days

#3 posted 07-03-2013 08:59 PM

Good idea. Also could be used to press grapes into wine.

-- If you believe you can or can not do a thing, you are correct.

View Jim Bertelson's profile

Jim Bertelson

4173 posts in 3160 days

#4 posted 07-03-2013 09:39 PM

I love home made gizmos….........but you knew that….......(-:

It fits all your parameters, and doesn’t take up much space when knocked down. Using the holes in the bench was the trick.

Happy Independent Thinker Day…......................

-- Jim, Anchorage Alaska

View Karson's profile


35120 posts in 4396 days

#5 posted 07-03-2013 09:42 PM

Lew. Way to use to older gray matter to come up with a young man’s fixture.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia †

View grizzman's profile


7836 posts in 3298 days

#6 posted 07-04-2013 12:30 AM

a really good jig lew, i love making jigs, its the best to try and figure out a way to make something on your own that will accomplish what you need done, keep on jigging…lol…grizz

-- GRIZZMAN ...[''''']

View Roger's profile


20928 posts in 2799 days

#7 posted 07-04-2013 01:28 PM

Now that’s a serious clamping jig

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed.

View lew's profile


12056 posts in 3750 days

#8 posted 07-05-2013 02:10 PM

Drew and Steve- Thanks!

Geoff- Thanks! Maybe I’ll try some wine making if segmented bowls don’t work out!

Jim- Thanks! Hope you had a relaxing 4th!

Karson, Bob and Roger- Thanks!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View sedcokid's profile


2731 posts in 3594 days

#9 posted 07-11-2013 12:08 PM

Way to go Lew!! I love it~

Thanks for sharing

-- Chuck Emery, Michigan,

View lew's profile


12056 posts in 3750 days

#10 posted 07-11-2013 01:29 PM

Thanks, Chuck!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View helluvawreck's profile


31044 posts in 2862 days

#11 posted 07-11-2013 01:31 PM

This is a great jig, Lew. You did a fine job on it.

helluvawreck aka Charles

-- helluvawreck aka Charles,

View lew's profile


12056 posts in 3750 days

#12 posted 07-11-2013 03:30 PM

Thanks, Charles!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View ldl's profile


1135 posts in 2360 days

#13 posted 07-13-2013 02:55 PM

Lew I too need a clamp for my segmented bowls I am just getting into. This looks good. Going in my favorites.

-- Dewayne in Bainbridge, Ga. - - No one can make you mad. Only you decide when you get mad - -

View a1Jim's profile


117090 posts in 3572 days

#14 posted 07-13-2013 03:32 PM

Cool idea nice work

-- wood crafting & woodworking classes

View lew's profile


12056 posts in 3750 days

#15 posted 07-13-2013 03:52 PM

Thanks, Dewayne and Jim!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

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