LMI Bridge Drill Jig - Luthier Tips du Jour Mailbag
In this episode, luthier Robbie O’Brien shows how to use the old version of the LMI Bridge Drill Jig.
Video Transcription
[on-screen text reads: Luthier Tips du Jour Mailbag]
Mailbag question: Can you share some advice on how to drill bridge pin holes in a straight line?
Robert O'Brien: Today's Tips du Jour Mailbag question comes to us all the way from England. "Robert, I'm having trouble drilling my bridge pin holes in a straight line. Can you offer any advice? Nick in England."
Nick, I feel your pain. Drilling six holes in a straight line is a lot harder than people might think. Fortunately, LMI has a jig that solves that problem. It's called the Bridge Drill Jig. Right now, on my bench, I've got an 1890 Martin Parlor guitar that I'm doing a restoration on. I had to remove the old bridge. I'm making a new bridge. And I have to drill the holes in exactly the same location as the holes that are already in the guitar. And this jig makes that very easy.
Here's the 1890 Martin Parlor guitar. Here's the old bridge that came off. And this bridge was put on there by the current owner 60 years ago. So when that removed, now I already have a series of holes. Since I'm making a new bridge, I want those holes to match perfectly with these holes that are already drilled in the top and in the bridge patch underneath.
Using the LMI Bridge Drill Jig
At the same time, one of the problems that these old guitars had was intonation. So when I saddle the slot, I can solve that issue as well. So to help me put those holes in the straight line, I'm going to use LMI Bridge Drill Jig. So the bridge is made to do a variety of different string spacings, and I'm going to be using the 2 5/16 string spacing. So I'm going to place the bridge into the jig. And notice that I've already marked the first and the sixth string. I'm going to place that in there. I'm going to now use the 2 5/16 indexing pin and place it in the first hole there. And then down underneath here, line the bridge up with my line that I've put there for my first hole.
Once I'm happy, I lock it in place with this little set screw here. I then take my indexing pin, place it in the sixth hole, and then down underneath here again, I'm going to line the mark that I put for the sixth string with the indexing pin. Once I'm happy, I lock that in place. Remove the indexing pin. I can now go to my drill press and drill six holes in a straight line.
[Robert drills all the holes using a drill press]
Once I've finished drilling the holes, I release the set screws, and I now have six holes in a straight line. And I can continue making the bridge. So, Nick in England, thank you very much for your question. I think you'll find that if you use the LMI Bridge Drill Jig, not only will you be able to drill six holes in a straight line, but you'll also have the correct spacing, so happy building.
[on-screen text reads: More Luthier Tips and online courses available at www.obrienguitars.com. Private and small group guitar building and finishing instruction available.]
