I have seen some jigs on the internet for giving a knife blank a "grind" or profile. This is the step before the final edge that is used for cutting. I have started to work scrap metal into knives, so I thought I would try my hand at making one of these jigs.
I wanted it to 1) fit my small work bench / project table, 2) be inexpensive, 3) be easy to construct, 4) really work!
Step 1: Wooden Base Assembly
My first step was to gather some scraps of wood. I had oak on hand. I think anything would work as long as it is not warped. Plywood would be fine, too.
I cut the pieces to form a "T".
I cut the long piece to fit across my work table, so I could clamp the finished "T" top and bottom.
A board was placed across the top of the "T" pilot holes drilled, then screwed together.
Step 2: Metal Materials
I had some old shelf brackets around. I knew I could use these to brace the jig in its final form. But I needed two pieces of "L" shaped utility steel. Found them at Lowes.
I used small boltds and nuts to fasten the braces to the "L" steel.
The view from the back shows how this gives a "U" shaped profile if viewed from above.
I used clamps to hold the entire assembly to the table.
Step 3: Knife Placement, Use of the Rod
I clamped a small portable vise over the long end of the wooden "T" and over the table top to secure that end of the jig.
Next, I screwed my knife blank to a piece of wood, and placed this in the vise.
I used a 3/8" steel rod as the angle guide for the jig.
Place the rod in one of the jig holes and check for the desired grind angle.
Step 4: Placing and Using the File
To use the jig, place a metal file under the rod and on top of the knife.
By changing the placement of the rod in the hole, you can change the angle of the file "grind"
Step 5: Using the Jig 1
I made a knife blank from a circular saw blade. I put a fairly fine edge on the blade with sandpaper sharpening. I don't mind the time it takes. But the blade still didn't cut the way I wanted. The angle of the cutting edge and the over all profile of the blade edge didn't taper enough. The transition from edge to steel blade was too abrupt. My goal was to give the blade a more gradual transition. In my way of thinking about the blade, I needed to take some of the shoulder off the profile. First step was to mark the edge with marker. I didn't want to mess up the sharp edge that was already there.
I laid out the coarse and medium files I would be using.
I also added numbers to the holes in the jig so I could keep track of where I was in the sharpening steps.
Step 6: Using the Jig 2
I started in hole # 2 with the coarse file.
Someone asked if I taped the file to the rod. No, I found that placing a hand on each end of the file was fine.
In the next picture, I hope you can see what the file was able to take away. The edge remains untouched.
Step 7: Using the Jig 3
I moved the rod up to the next hole and kept using the coarse file. In these steps I counted 12 strokes for each level, all the way up to #10. I kept watching to make sure that I still had a slight indication of marker.
Then I switched to the medium file and repeated the steps above.
Next I switched to a sandpaper -covered block.
Step 8: Finish
I could tell that it was working well as I repeated the steps with the sandpaper.
The blade was nicely reprofiled and ready for and sharpening for an even finer edge.
I could have also increased the grit and continued using the jig...
ALL THE BEST...