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I just bought j hall side Bending machine from a guy off Craigslist. He was getting out of the hobby and threw in enough kerfing to make about 10 guitars. Upon closer inspection i realize that the kerfs are reverse style which i have been wanting to try, even cooler, right? But not so fast. I think he got this stuff from someone on Ebay and I'm not to trusting of unknown sources. I noticed that this stuff looks high quality and is made of mahogany but boy does it look narrow. Compared to Martin regular kerf it is much more narrow. The Martin kerf measured at its widest point is 6.21mm/0.245 inches and the reverse stuff is 4.15mm/0.164 inches. I'll put a photo in if i can figure how. My question is, is this stuff too narrow to provide a decent gluing surface?

Here's another photo. The Martin stuff is on the right.

No, it is just fine.

After looking at your photo, I wonder if this is reverse lining. It looks like the round over is on the wrong face. But it could be my computer and my old tired eyes.........!!
Tom

It does look thinner than normal to me too. LMI's "standard" kerfing is 7/32" thick. I don't know enough to know if thinner is okay. I think it may depend in part on how thick your top is and how deep/wide your purfling/binding channels are. The kerfing needs to extend under the purfling channel to support the un-channeled top.

you would like to have about 1/4 in of glue surface with the side. If you have that your good to go

Thanks John. In that case this kerf is awfully thin, if my sides were 0.09 + kerf at .164 my gluing surface would be right at 0.254 which is right at your 1/4" limit. I guess that's doable but it makes me a little nervous when I see how much more gluing surface the Martin kerf gives me. One more thing to worry about, right?

:) Danny

Tom and others, the rounded end gets glued facing the opposite side of the gluing surface - you can turn it in either direction depending on which side of the guitar that you are using it on. The guy that gave it to me glued this kerf up like you would regular kerf but I'm pretty certain it is reverse kerf - it matches all the photos that i can find of reverse kerf, it is extremely flexible and has no problem bending in either direction and it does not have a triangular cross section like most regular kerf that I have seen.

the kerfing isn't reverse the curve is in the wrong direction.

I see what you mean. Thanks for everyone helping me figure out what I have! According to to Johns 1/4 inch guidance this stuff wouldn't work out if I wanted to use thin sides but it would work if I used thicker sides.

If it was the only kerfed lining available I'd glue some appropriate thickness veneer to the inside of the
sides and then glue the linings on to the veneer in order to make it work. Wouldn't be my first choice, though.