Just wondering if anyone has taken a flat bridge and used a radius sanding block to gently create a radius bridge with any success? I realize that there would be less cap material on the sides of the bridge, but it seems Snuffy Smith radius bridges are made this way…
I guess I’d also have to refill the string slots, so wondering if there are any tricks to that?
Also, it seems like a lot of third-string-compensated bridges have a little round groove drilled into the cap at the front of the string slots I’m wondering if all it takes is a certain drill bit or something to be able to create that the same way?
Any advice or help is greatly appreciated, thanks!
The answer is yes, assuming there is an adequate thickness of ebony on top of the bridge and the bridge is slightly taller than you would normally use. If your normal flat bridge height is 5/8” and you replace it with a 5/8” radius bridge the measurements of either bridge are taken at the string heights on either end of the bridge with the middle stings arching higher toward the center. I shape mine with sandpaper using an existing radius bridge as a pattern. The middle string slot will not change but strings on either side will drop with the new radius of the bridge. No need to refill string slots.
To compensate the third string use a jewelers file and file a V about halfway into the ebony at the top corner of the bridge at the middle string. I usually take a round file and round out the filed V slot. I think it looks better and probably clearances the string a bit better than the V.
Here is a picture of a Scorpion bridge on my Cox Kentucky 5 that I have modified from flat to a 16"radius. Look close at the middle string compensating relief, it's a bit hard to see in that picture. I use the same compensation technique as shown on bridges on the Snuffy Smith website.
Edited by - Pick-A-Lick on 12/07/2024 11:05:20
Rather than using a radiused sanding block and sanding the top front-to-back, I think I get a radius gauge either from Stew-Mac or a lower-cost seller. I'd mark the radius on one face of the ebony, then file or sand the top to shape.
As to the notch for the compensated third string slot, I guess some makers give them rounded bottoms (suggesting a flat-bottomed drill or router bit) but I've also seen squared-off notches, suggesting a small flat file used on an angle. That's how I compensated the third string on one bridge.
Edited to add: Slapping my head. Of course, a rounded/semi-circular notch can be filed with a round file. And some type of needle file can used to create a V-shaped opening in front of the set back witness point. Lots of options for shaping the notch, depending on your tools, ideas, and skill.
Edited by - Old Hickory on 12/07/2024 11:29:57
I use my Stew Mac radius gauges a lot.
8 individual "T"s and two 4-sided plates with 7.5" to 20" radii.
I got the set to be able to mail bridges to different fretboard arches.
It saves a lot of time to find the neck arch with a gauge and for a matching bridge and nut.
Banjodaddy some bridge makers make a 5/8ths radius bridge with slightly taller than 5/8ths height at the center of bridge and creates a 5/8ths height (+ - ) at the outer strings which seems fine by me . I personally make a 5/8ths bridge basically with a 5/8ths height at center string and then put the radius on. This will put the outer strings at a slightly shorter than 5/8ths height which has worked for years for me without customer complaints about bridge being too short on the outter ends . For 3rd string compensation for many years now i have used a 1/8 inch wide rat tail file which usually can only be bought at retail stores in a pack of 4 or 5 in an assortment package . i put the bridge on the very edge of work bench where i can get the handle of the file down below the bridge ..i then put the file in the 3rd string slot at about a 45 degree angle and take baby step strokes into the slot until i get where i need to be which is about 40% removal . the file will try to pull you out of square with the string slot because the file cuts material out at an angle ...so baby steps are critical to keep centered on string slot
Thanks Mike et al, great info!!!
Here are some freebie radius sizing templates to help you figure out what you need:
banjobridge.com/help/help-radius.htm
By setting the outside strings at 5/8 above the head the 3 rd string will have the same relationship to the fretboard at the correct radius according to the frets.
