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Sheesh John it's unforgivable to say the wrong thing here. You don't see me ever doing that now do ya?

Seems like a very good time to let others know that when I was just starting out I would call John and get advice and buy things too, molds, benders, forms etc. John was an early mentor of mine AND friend.

Thanks John!!!

I have built about ten true flat top guitars. They are different. Don't know how quite to describe it. String tension puts a dome in the top anyway. One thing I will add is that for every guitar that I do put a radius in the top I make an mdf clamping call that is also radiused(is that a word?) that fits the top and around the bracing perfectly. Then of course that is used as a clamping caul to the radiused bridge.

But again for my normal very shallow radius I just glue the bridge flat. With the shallow radius and the flat bridge plate it tends to flatten out. OR at least very light finger pressure will hold it down.

Do you guys put a radius in the bridge plate too?

That has to be the nicest hot-headed moment ever, because I didn’t even notice it.

As to the OP, I use a small radiused dish from forum sponsor Luthier Suppliers, specifically designed for putting a radius on the bottom of the bridge.


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I build with a 25’ top radius (braces glued in a dish—bridgeplate sanded to radius in the dish before gluing). I made a block with 25’ radiused surface to go under the belt on my 6x48 belt sander. It takes a minute to sand the radius to the bottom of the bridge. I do this to the bridge blank before I cut and sand down the top of the bridge. Occasionally, I have sand the bridge bottom in place for a more perfect fit, but usually, the bridge fits perfectly. I use 315g hot hide glue for the bridge to top joint and use a vacuum clamp when I glue it. I see no reason for the bridge not to fit perfectly.

Do you by any chance have a photo of that 25' radiused block in action on your belt sander?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Note that since the block is a section of a sphere, the orientation doesn’t matter. I sanded it to shape in a radius dish. The action picture is staged. I won’t be doing bridges again for a few more weeks.

Thanks a lot for taking the time to post those photos. I was wondering how you secured the block under the belt. I'm going to give that a shot. Sanding the radius into the bridge bottom by hand is one of my least favorite things to do.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I save one belt just for that purpose. It doesn’t exactly ride flat after that operation.