Thread: Knifemaking photo-essay (2)

1) This is a hardened, tempered blank I made six or seven years ago. After heat treatment the blanks have a hard, adherent skin of black iron oxide, which I sandblast off.

2) Surface grinding the blank with a 60 grit belt.

I now check the blank for straightness by looking along the top from the butt end. With practice you can see a bend of about 0.5 mm per 100 mm of length. I won’t go into detail except to say that I can generally either “hide” or correct a bend of less than 1 mm per 100 mm.

3) Surface grinding the blade flats with a 180 grit belt. I take off about 0.001” (0.025 mm) per pass until the 60 grit scratches are removed.

Tapering the tang.

The surface ground blank is about 3.7 mm thick. If, while tapering, I aim to remove a maximum of 1.0 mm per side on the tang, that would leave the butt end 1.7 mm thick. Given that the tang is about 110 mm long, the required taper is approximately 1 mm per 100mm of length. The magnetic vice is 300 mm long, so I would need to raise it 3 mm to get the desired taper.

4). The setup for tapering the tangs, with one end of the magnetic vice raised 1/8” (3.175 mm).

1) Grinding the taper with a 60 grit belt.

2) How NOT to taper the other side of the tang. In the setup shown here, I support the tapered end of the blank (pink arrow), then grind the second taper. However, after once doing it this way, I discovered the new taper wasn’t flat -- it had a bow in it.

3) How to grind the second taper. The magnetic vice is raised 1/4” (6.35 mm) as indicated by the pink arrow. Make sure the recently-tapered side is attached to the magnetic surface!

4) The tip of the blade is supported, and then the new taper is ground.

5) The tapered blank.

1) I’ve swapped out the surface grinder’s belt sanding attachment for a fine white grinding wheel. A machine vice, which is bolted to a thick steel plate, is placed on the magnetic vice. I’m aligning the vice jaws at a 90 degree angle to the face of the grinding wheel; once aligned, I switch on the magnetic vice to hold the machine vice in place.

2) Grinding a recess for the guard, taking multiple shallow cuts.

3) The pink arrow points to the newly ground recess.

4) Fine burrs are left on the blade flats, which I’m sanding off with 320 grit abrasive cloth.