Sliding Vise Parallel Guide Mortise and Tenon

Parallel Guide Mortise in Vise Chop

2010.01.23

I laid out the mortise for the parallel guide on the back of the vise chop, using squares, mortise marking gauge, and marking knife.  I set the mortise marking gauge pins to match the width of my 3/8″ mortise chisel.

Then I drilled a hole in the middle of the mortise with a brace and bit to provide a place for the chips to go.  I began chopping with the mortise chisel next to the hole, going in about 1/8″ and then stepping back about 1/8″.  I stopped short of the narrow ends so as not to bruise them while levering the chips.

Laying out mortise for parallel guide in vise chop
Chopping mortise for parallel guide in vise chop

I kept making passes back and forth, chopping the mortise deeper each time.  Finally I had it down to the depth I wanted, except for the ends.  I carefully chopped down about half of what remained, then used a bench chisel to pare or lightly chop the rest.  I finished up with my 3/8″ corner chisel.  Unfortunately, I have mangled the edge on this chisel somewhat, and have not resolved the best way to resharpen it, so it did not work as well as it should.  Of course, paring white oak end grain is pretty demanding on a chisel, so maybe that’s as good as it gets.

Chopping mortise for parallel guide in vise chop
Finishing mortise for parallel guide with corner chisel

Parallel Guide Tenon

2010.01.24

I set up a guide for my crosscut saw to make the shoulder cuts for the tenon.  Then I clamped the workpiece to the workbench leg and sawed the cheeks, working diagonally from each corner.  After that, I sawed straight across to finish the middle.

Sawing shoulder of tenon on parallel guide
Sawing cheek of tenon on parallel guide

I did some cleanup with my shoulder plane.  After some test fits and tweaking, the tenon slid firmly into the mortise.  In fact I had to stand on the chop to pull the parallel guide back out.

Then I realized that the parallel guide was not perpendicular to the chop… it was leaning to one side.  Hm.  Somehow I cut the tenon off parallel, or the mortise.  Or maybe both.  I pulled the parallel guide out, turned it over, and put it in the other way.  Now it is perpendicular, hah.

Parallel guide tenon
Parallel guide in vise chop

My first plan was to glue and drawbore peg the tenon in place.  But thinking about moving from one place to another, and breaking everything down, the vise chops with parallel guides sticking out perpendicular would be awkward to pack.  So my next thought was to use long screws through the sides of the vise chop instead of glued pegs.  But after I put this mortise and tenon together, the grip is so tenacious I think I won’t bother with any mechanical or adhesive attachment.  The normal operation of the parallel guide will push the tenon into the mortise, so there’s really no force trying to pull it out.  If it becomes a problem, I will revisit a more permanent attachment later.