Woodworker's Journal winter-2009, страница 72

Drilling Rung Mortises with Jigs

To simplify drilling the rung mortises, I devised two very simple rung-mortise jigs: the side-rung mortise jig (SRMJ) and front-rung mortise jig (FRMJ). They'll work for any chair with back rungs 100 degrees from the side rungs, and that includes many, many Shaker chairs. In use, you'll need to support each of these jigs on a large, flat surface on your drill press. Build both the jigs now from scrap, following the Drawings on page 70.

The purpose of the FRMJ is to keep the posts from rotating as you drill the 5/8" mortise holes. Snug the first post up against the side of the jig so the layout line along the length of the post is parallel to the jig's long leg. Then lock the post into place by turning two screws into the end grain of the post.

With the post locked, line up the first mortise location under your drill bit. (Be sure to have the drill press set to drill a 15/16"-deep hole in the post. This is best established by drilling into a scrap test piece turned to the correct diameter.) Drill the back-rung mortises in your back posts and your front-rung mortises in your front posts. (Editor's Note: Be sure not to drill any side-rung mortises with the front-rung jig — it's an easy mistake to make and impossible to fix without remaking new leg blanks.)

Before you put the FRMJ away, drill a pair of l/2"-diameter mortises near each end of the top two backrest rungs (the top and

The author details the crest rail with decorative carvings using a sharp knife and paring chisel, followed by careful sanding.

bottom elements of the back panel). These are the mortises that will accept the 7/16"-diame-ter tenons on the ends of the backrest side posts.

Assembling the Ladders

The front ladder is now ready to be assembled. Do a dry fit, then

Chop out the crest rail mortises in the back posts with a 1/4" mortising chisel. Make the mortises 9/16" deep and 1V long. Use a curved support to brace the post from below and to keep it from twisting.

apply glue to the all the joint parts and tap the ladder together with a soft mallet to start the tenons. Close the joints with a long clamp. Check the ladder with a framing square. Rack it into square if necessary, making sure it lies flat on a flat surface, then set it aside to cure. DO

After you've glued your front ladder together, set up the side-rung-mortise jig (SRMJ) as shown so that it will bore a 15/16"-deep mortise in the center of the posts. Then drill the three side-rung mortises in one post, turn the ladder around, and drill the three side-rung mortises in the other post. Next, rotate the jig 180 degrees on your drill press table and drill the side-rung mortises in the back ladder.

72 shaker-inspired woven rocker