Thread: Knifemaking photo-essay (3) - Making the guard

The previous post in this series was: https://www.nzhuntingandshooting.co....ay-2-a-105013/

In this post I’ll describe how I make the guard.

1) Measuring the thickness at the ricasso (3.66 mm).

2) Measuring the guard slot’s required depth (24.5 mm).

I use a horizontal shaft milling machine to cut the slot in the brass guard.

3) Aligning the jaws of a swivel vice so they are at a 90 degree angle to the face of a slitting saw.

4) Confirming the slitting saw will clear the vice jaws.

I make the guard from a brass block 19 mm wide, 12.7 mm deep, and 50.8 mm long.

1) The brass block protrudes 28 mm. It is pushed flat up against the face of the slitting saw, and the vice jaws are tightened.

The widths of brass and blade are 19 mm and ~4 mm respectively. 19 - 4 = 15, 15/2 = 7.5. To centre the blade in the guard, make the first cut 7.5 mm in from the edge of the brass block.

2) Setting up the cross slide so that the first cut is 7.5 mm in from the edge of the block.

3) Making the first cut.

4) Confirming the slot is deep enough. It had to be at least 24.5 mm, it was actually 27.0 mm.

1) The slitting saw cut a slot 2.55 mm wide. I put a dial gauge on the cross slide, brought it over 1.00 mm, and cut again, giving a nominal slot width of 3.55 mm. The ricasso was 3.66 mm thick – when I checked for fit I could, with some effort, force the blank into the slot. I then brought the cross slide over in 0.03 mm increments, cut, and tested for fit. I did this until the blank was a smooth force-free sliding fit into the slot (perfect!).

2) Sanding the faces of the slotted brass block.

3) The guard recess in the blank has a small radius (pink arrow).

4) Filing a chamfer in the bottom of the slot to clear the radius in the guard recess.

1) Checking the fit of the guard. The fit is good if I can’t see any light at the joint between the face of the recess in the blank and the guard (indicated by the pink arrow).

2) Two views of the fit between the guard and the blank.

3) I like the appearance of an angled front guard face. I set the table of the disc sander to 15 degrees and grind a chamfer up to the slot, doing most of the job with an 80 grit disc. I do the last 10% of the grind with a 240 grit disc, as shown here.

Where do you source your brass from? I'm struggling to get any supply for small quantities.

Originally Posted by turtleSO

Where do you source your brass from? I'm struggling to get any supply for small quantities.

Used to get it from Mico Metals Wellington 10+ years ago. Just did a Tardeme search, check out https://www.trademe.co.nz/a/marketpl...ing/4731197414