Acoustic Guitar Construction

My bridge pin holes need to be reamed out as the pins do not seat full depth. In checking for reamers I see that they come in several different degrees of taper. How do I determine which one I should order?

I've thought about wrapping some sandpaper around one of my pins as I think that would do the trick perfectly. Is this a viable alternative?

The holes in the bridge are normally 3/16" (KMG machining is programmed as such) If you don't want to purchase a reamer, there are a couple of options that work fine. Of course drill a 3/16" hole in a scrap piece of hard wood to test your process. The first is to use a 1/4" rat tail file, I have one that I broke off and chuck into my drill, I marked the desired depth with a piece of tape -- very quick and easy. A less aggressive method is to use the bare handle end of a bastard file, the angle is correct for most pins and the hardened metal has very sharp corners that shaves the holes easily. The latter is a trick I learned from Irvine Sloane.

Good suggestions, Kenneth.

Generally, some Martins & Gibsons used 5 degree tapers (as well as some Collings & Bourgeois), but like many others I am using an affordable 3 degree reamer (from Grizzly tools). Just be sure that the reamer you use (if you use one), matches the taper of the pins. I like the look of bone pins, so I like to use them.

Our "store bought reamers" are from a production metal working tool supply house -- simply a straight cut pin reamer .144" on the small end. The taper is 1/4" per foot which equates to approximately 2.5 degrees. I also chuck these up in a hand drill again marking the depth with piece of tape. Since these can be purchased for as little as $6.00 I find the $55 priced reamer from the Ohio based supplier very humorous.

A Rat tail file works for me also. I do it by hand,when the pins fit I'm done.

I've seen this very same 5 degree reamer being sold by luthier suppliers and luthier supplier "wanna bees" for as much as $32 ! Oh a few have what must be $28 pieces rubber/plastic tubes on the handle.

http://www.harborfreight.com/t-handle-reamer-66936.html

I found a vendor on Ebay peddling a #1 tapered pin reamer, tapering .1447" ti .1798". Now, 3/16" = .1875". This reamer would never touch the sides of a 3/16" drilled hole. So I gotta be missing something. I could find no other reamer offered that seemed to fit the task we have for it. Advice will be much appreciated. Thanks.