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I have a guitar with a K&k that I’ve struggled with for 10 years. After using a Barbera in another guitar for about a year and loving it, I’m ready to switch. Problem is it has a 3/32” slot and Barbera requires 1/8”.

I (used to be) an amateur luthier, having built an acoustic from a kit and repaired a handful of guitars… a number of years ago. So I am brave enough to attempt this but realize I don’t know what I’m doing.

Initially I was going to cut the slot with a router, but that seems risky and required some stout/precise fixturing. But instead, Is it possible to sand 1/32” off? What is a good method? And I wondered if I should take material off the back or front? Maybe depending on how well it’s compensated? I could take measurements to see where the compensation is. I thought about getting a 1/16” piece of steel and spray glue sand paper on it?!? Back and forth. Stewmac also sells saddle slot files that hit the bottom, but not the side.

Suggestions?


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Don't think sanding's gonna work. Possibly wide sharp chisel but need skills and probably still won't end up perfectly straight. Plus difficult to make the bottom flat.

Need to rout. Check the intonation after you set up and find the ideal spot.

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_________________
Pat

I would not attempt this unless you are jigged up and experienced.

Instead take it to a pro Luthier and you live in an area with plenty of them. They will have a saddle jig and perhaps a saddle mill, we have both.

The process is to measure the scale length and then determine where to widen the slot the back, front, etc. It may be that the compensation is insufficient or too much too. All of this can be corrected including plugging the entire bridge and recutting a brand new slot in one hour's time or less. That makes this not a very expensive repair to have done commercially.

Should be able to have a new, correct saddles slot of any appropriate size cut for a bit over $100.

To give you an idea how precise this needs to be our saddle mill which is the gold standard and the last one we sold was close to $4K is vacuum clamped, laser guided and will make lunch for us if we ask it... But seriously this is an operation that I would not even attempt in my home shop even though I've done it many times if I did not have a proper saddle mill and jigs to hold it all in place.

PS: We don't do shipped in work so not trying to get any business we have more than we need and turn most of it away these days.

I have done this several times and the best way is to completely fill the slot with a piece of rosewood, then route the new slot. StewMac sells a jig just for this



In theory you should be able to align the bit with the existing slot but if you fill it first you can put the new one exactly where you want it. Remember that the bridge top is curved so don't let the router (dremel) ride on it, you want the slot bottom perfectly flat for a UST.

I'll add that I'm not familiar with the Barbera transducer - I install lots of K&K's but a number of manufactures like Fishman sell 3/32 UST's