Guitar 101: The Bridge

The next step in the process was to make the bridge. Keeping with my established color and wood tone the logical choice was a bridge made from rosewood. I cut a piece of rosewood and created a blank approximately 2"x7"x3/8". I based the basic shape and size of the bridge from plans printed in the Guitarmaking, Tradition and Technology book by William Cumpiano. Before I strated to shape the blank I sanded the bottom to conform to the radius of the guitar body top. To get a perfect match I placed a half sheet of 80 grit sandpaper on the guitar top and sanded the blank using very light pressure until I got consistent scratch pattern on the bottom.

Rosewood bridge blank.

Sandpaper in position on guitar top.

Sanding using light pressure.

Continue sanding until even pattern on bottom of blank.

Once the bottom of the blank fit the contour of the top I was ready to start shaping. I transferred the basic shape of the bridge and cut it out on the bandsaw. I switched to the drum sander to smooth out the shape and start reducing the thickness on the outside edges. I used the drum sander to get the basic shape and contour of the top of the bridge and finished by hand sanding down to 320 grit sandpaper. At this point I transferred the peg hole positions and the angled slot for the saddle from the plans. Because of the dark woodtone I found that I needed white position markings. I printed off a copy of the plans and used white chalk to rub the back of the print. I then flipped the print over and positioned it on the rosewood bridge. I then traced the peg hole positions and the saddle slot transferring them to the wood in white.

Peg hole potions and slot marked in white.

Bridge in rough position on guitar top.

I then used a drill press to drill the peg holes using a 3/16" brad point drill bit. Once the holes were drilled I used a countersink bit to bevel each hole. I then reamed each hole carefully with a 5 degree reamer until each pin fit perfectly. The next step was to rout the slot for the saddle. I built a simple jig to hold the bridge with a straight piece of wood set at the same angle to act as a guide rail for my Dremmel router. The slot not only needed to be at the right angle but also needed to be the right depth and the right thickness. The depth was fairly easy to get because my precision router base let me adjust the bit depth slowly as I made several passes. The correct thickness of the slot proved to be a bit more difficult. The saddle I had was a hair over 1/8" thick, so my 1/8" bit was slightly small. Once I had the correct depth I applied layers of masking tape to the guide rail and made more passes with the router. The tape pushed the router down slightly making a wider cut. This seemed to work. I probably could have just sanded the saddle to get the right thickness. I don't know if it would have been easier to do that or not. The final step was to polish the bridge with 0000 steel wool.