Drilling Guide for Forefoot and Stem

[bob mitchell]

Drilling long bolt holes through thick pieces of wood can be a real challenge. Today I did the Bobstay Staple through about 16" of my new stem. This was an especially challenging proposition because not only does one hole have to come out in the back center of the stem, but another hole parallel to the first and about 2" away must also be drilled.  The Bobstay Staple is the "eyehook" (for lack of a better word)  where the bobstay from the bowsprit connects to the stem.

This is a shot of the drill guide that I made to do such long holes.

The way I made it (although it appears obvious a couple of points are worth mentioning) was to square up some high quality 2x6's and then layout a couple of holes (3/4" for my pipe clamps) and one 1/2" hole centered in between them. Then using my drill press I bored all the holes with lumber squared to the drill in a vice, thus insuring that in the field if I oriented my "drill guide block" correctly I would get a stright hole because I had 6" to guide me. The back block was done the same for the clamps. AN ESSENTIAL IDEA IS THAT BOTH BLOCKS HAVE CENTERED LINES TO LINE UP THE BLOCKS WITH THE STEM, ENSURING THAT THE HOLE COMES OUT THE CENTER OF THE BACK SIDE. The location of the hole in terms of the up or down of the stem is indicated by laying a straight edge parallel to the guide hole on the front drill guide surface and seeing where it come out in the back.

        If you were working with a front and back that were parallel it would be easy, but when you start dealing with non parallel curved surfaces it becomes a little more tricky. As shown, I tacked some plywood on the stem to keep the guide from creeping as I tightened. I also checked a lot of "squares and angles", but in retrospect I realize that if the width marks mentioned earlier are lined up, and then the hole location can be projected by the surface of the front guide block. Be sure to subtract the thickness of 1/2 the 2x to locate the center of the hole when you mark the surface in the back. Harbor Freight has some good auger bits (like shown), 5/8,1/2,and 9/16, 18" long, the set for $20. One Irwin bit, only 16" long, (critical in my situation), costs $23 at home depot. Harbor freight also had regular twist bits for wood that were 25" long, the 9/16" that I used to ream out my holes. The Dewalt drill is brutal and I really like the 750 RPM's and TORQUE for wood,BUT IT WILL BREAK YOUR WRIST IN A HEART BEAT IN  1/4" OR GREATER STEEL. One time I spent a whole day finding a low torque

Ryobi 1/2" drill to avoid being on a scaffold drilling steel with that damn dewalt!