Ellsworth style thickness gauge

[Chuck Bjorgen]

I need a refresher course on the making and use of the wall thickness gauge I saw David Ellsworth demonstrate at a Minnesota Woodturners Association meeting last year. I seem to recall his using heavy wire. A photo would be very helpful. Thanks in advance.

 

[Ron Overholtz]

David is into low tech stuff. I've been using his idea for the last 10 years or so
of a low tech gauge for hollow forms. A thin 1/4" metal rod available at any hardware store will work & they're cheap . Buy a few to make diferent sizes and depths. Be sure to grind off the rough ends after you cut them to length so you won't mar the wood. Then it's only a matter of bending it into almost a circle leaving a little gap to judge thickness. I bend mine back and forth depending on if I'm roughing out or going for a final thickness.
Ron

 

[Chuck Bjorgen]

Thanks for your input, Ron. A good friend of mine took detailed notes at our club Ellsworth demo last year and shared them with me yesterday. The recommended rod was 3/16" galvanized (or zinc coated) that is sold in three foot lengths at hardware stores. As you said, the rod is bent into a circle of sorts. I would add only that one tip is bent to aim at the other at a right angle rather than having to the two tips meet. This is not a precision instrument but rather one that can give you a general impression about the consistent wall thickness of your hollow form. To use, adjust the gap to 1/4-inch or larger, run the tip along the inside edge of the vessel and watch the gap along the outside shape to detect uneveness. You can easily change the shape of this jig to conform to the contours of the piece you're working on.

As you said, Ron...pretty low tech but useful.

 

[john lucas]

Sounds like you have the idea on how to build it. I use the same thing in a smaller scale to hollow ornament balls. The critical thing is to have the rod perpindicular to the area being measured. If you don't you will get an erroneous reading. I cut through 2 because I got in a hurry and didn't measure correctly.

 

[Ken Grunke]

copper tubing

I use small copper tubing for my calipers, it holds it's shape better but is still easily formed to any shape you need.
Flatten the ends, and nip them off at an angle then round over the points with a file.
A brakeline might work really good also, although I haven't tried that.
I've tried steel wire, it's more "springy" and copper is less likely to scratch the wood.

 

[Bruceyp]

If you hurry...

I have made those circular thickness gauges from the wire that was inside those political signs that were stuck in everyother front lawn in my neighborhood. There's nothing like material recycling!