I really liked the lift-top coffee table project that appeared in issue #79 (Oct/Nov 2017), but I am particularly interested in the shop-built mortising jig that employs Micro Jig’s new MATCHFIT clamps. I suppose that I could use the photos to create my own version, but a little advice or sketch would be a real time saver.
—Stanley C. Pearse, via the internet
Consulting Editor Tim Snyder responds:
Thanks for writing. Considering that I used my jig not only for mortising, but also to support the rails when routing the decorative beads, it deserved a better treatment.
I had planned to take some photos; however, I’m sorry to say that my puppy borrowed the jig for use as a teething aid. Hopefully, this sketch, and few additional construction notes, will suffice.
Size your jig to suit. My long-ish version (32") enabled my jig to support boards when routing the edges of longer boards, in addition to serving as a mortising platform. Make the top of the jig at least 3" wide to provide good support for your router. The spacing of the dovetailed channels is up to you, but you should position them at least 1" away from the edge, or else the clamp pressure could split the plywood. (I routed the grooves in two passes, starting with a 1/4" straight bit, then a 14° dovetail bit.)
Assemble the jig in stages. I recommend completing the clamp board first. Then, fasten it to the base, and add braces every 8". Attach the top last, making sure that its outer edge is straight and smooth (to work with your router’s edge guide) and that it is parallel to the face of your clamp board. Keep the base open at the jig ends so you can clamp it to the workbench.
For the record, I’ve found that the MATCHFIT clamps are very useful for other applications too.
