QA: Jig for Bed-Bolt Mortises

Question: I would like to make Christian Becksvoort’s trestle table (FWW #193), which uses bed bolts to attach the stretcher. These bolts require very long holes in the ends of the stretcher and a small mortise for each nut. Is there a surefire way to locate the mortises in the stretcher even if I drill slightly off line?
-- Dan Morgan , Pearl River , NY
Answer:

Yes. I use a simple jig for bed bolts. Insert a bolt into the stretcher, and the jig hugs the bolt to align itself with the hole you drilled. The jig’s dimensions are determined by the length of the bolt you use and the thickness of the post.

Locating a nut mortise in a stretcher. A simple bed-bolt jig finds the proper spot for the nut that will secure a trestle-table stretcher. Click to enlarge.

Make the jig from scrap. Two tabs on the underside, equal in length to the thickness of the post minus the counterbore for the bolt head, will straddle the bolt.

Designate a front end of the jig, insert the bolt between the tabs, then mark and cut a notch in the front edge at the point where the bolt protrudes. In use, the notch will be aligned over the bolt’s centerline, and halfway along the threaded area. Mark the stretcher at the notch to establish the nut-mortise location.

Guide the jig with the bolt. Demonstrating with a bed rail, Becksvoort aligns the jig over the protruding bolt, brings the jig up to the rail’s end, and marks at the notch, which is centered over the threads of the bolt.

Using a square, mark in the mortise dimensions, then drill and chisel out the mortise. Repeat the process for the remaining bed bolts.