Soundboard Thickness Gauge
 

I'm running a couple of recently glued up soundboards through the drum sander. On the edges, I'm at .14" now. But the center seems to be getting overly flexible.

I only have a caliper to measure edge thickness. How important is having a deep throated gauge?

Can you make one out of wood and a reliable gauge or is the wood too unstable? If purchasing one, is there one that won't break the bank?

A couple of quick thoughts. Sure you can make one out of wood that could be stable enough with an attached gauge - especially if you calibrate with a test object each time.

Also, your drum sander is making a linear “cut” across the wood in line with the direction of the feed belt. For the majority of scenarios, you can check the thickness of the wood at the edge that’s in line with the center of the top to get a good idea of the center thickness. Usually if there’s discrepancy, it’s because the wood is cupping to where it takes more wood off the outside of the plate. Rarely do you sand more internally.

Hope this helps. The guys in the build and repair section of the AGF may offer more advice.

Can you lay it on a granite tile or piece of plate glass and then lay a straightedge across it? Then use feeler guages to see if there are differences in thickness under the straightedge -

Although I have a gauge on it you could always make it a go-no go gauge. The bottom stop is screwed into the wood and a screwdriver can adjust the depth of the opening to match the perimeter. You can then compare this depth to the middle.

https://i.imgur.com/lSzCFDp.jpg

Thank you! You gave me some ideas.

What I ended up doing is using a Betterly gauge designed for tablesaw and router use and modified it a bit. I used the tablesaw table for the flat reference and secured the Betterly setup so that the dial gauge was extended out around 8". Then I put the soundboard plate down and moved it around, keeping pressure on the board, close to the dial gauge pin.

I found out my concerns weren't warranted. The soundboard thicknesses were very consistent.