Making a Panel Gauge - Part 2

I've never been good with metal work.  I thought about buying an X-acto knife blade to use for the cutter in this panel gauge, but I decided to make a cutter from a piece of one of my thicker (0.039") card scrapers.  I hope the metal is good enough to hold an edge.

Hacksawed a bit over 5/16"

Filed it to a width of 5/16"

Then filed one end to a point and started putting an edge on one side

And got the final profile - all with a straight single-cut file

I used an off-cut from the stem of the gauge to practice mortising for the cutter and wedge.  This turned out to be very important.  In the following picture, the mortise on the far right was my first attempt.

First mortise at right, final practice try in center

I was a little worried about blowing out the wood to the right of the mortise when chopping and that's exactly what happened.

Can you see the end grain protruding?

So I decided to first drill out the hole with a 1/4" drill bit and then pare away the waste with a 1/4" chisel.  The mortise is 5/16" wide.  On the bottom it is 5/16" long and on the top it is 13/32" long.  The wall closest to the end of the stem is straight and the other wall is angled.  I took my time and pared carefully.

When it was time for the real thing I marked very carefully, drilled the hole, and pared away.  BTW, I started the mortise about 3/4" away from the end of the stem.

Mortise layout on bottom

And on top

Drilled from both sides to avoid blowout

Chiseled out the waste

Used an auxilliary light to see the inside better.  See the hump in the middle?

I pared away until a chisel laid on the wall was flush with top and bottom edges.  With the mortise cut it was time to fit a wedge.  I had a small oak scrap, already at 5/16" width and cut the angle to get an approximate fit.

Tight fit on bottom ...

But not so good on top (mind the gap!)

I tweaked the wedge until I got a tight fit top and bottom.  Then I trimmed the wedge and the back end of the cutter to get the lengths I wanted.

This cutter isn't going anywhere!

There are a couple important points about this picture.  First, the wedge sticks out of the bottom of the stem a little bit.  This allows you to overhang the cutter but not the wedge at the end of the bench.  A light tap loosens the wedge.

Tapping the wedge to loosen the cutter

On the other side, the wedge sticks up higher than the cutter so you can tap it to tighten the cutter in place.

Tapping the wedge to tighten the cutter

For finishing, I gave all parts two coats of shellac.  Then the stock and stem (except for the side that opposes the wedge) got a coat of wax.  What a difference in how the stem slides in the mortise!  No wax on the wedges so they will hold better.

Shellac drying (how exciting!)

In use, to tighten or loosen the stem at a certain location on the stock, it takes just a tap on the bench.  But it really holds TIGHT.  It's no wonder wedges were such an integral part of woodworking shops for centuries (and still are in some shops).

Tightening the wedge

Loosening the wedge

In use, the rabbet cut at the bottom of the stock will slide along the straight edge of a board.

Slides nice after waxing

And the requisite glamour shot:

The finished product

I almost forgot - I drilled a 9/32" hole in the other end of the stem for a tight fit with a pencil when I want a pencil line instead of a knife line.  If I ever use skinnier pencils or if the fit gets loose I'll put a screw in from the side to tighten it down.

Turn the stem around and use pencil for a non-knifed line

And there you have it.  Another "to-do" list item done.  Finally!  Now I have to wonder how and where to store this ...

Edit: I'd appreciate it if anybody can recommend whether or not I should harden and temper the cutter.  Thanks.