Grinding Technique

[Ed Tipton]

When making a knife, my first operations are to get the desired profile through a combination of forging and grinding, and straightening the blade. My next operation is usually to draw file the length of the blade to even out any "high spots" left over from the forging operation, and to rough in the plunge cuts with the file. Then, it's off to the grinder. I start my grinding by doing a lengthwise grind...again attempting to attain flatness. Once I get the blade sufficiently flat, I begin to gravitate to finer grit belts. I continue this process until at some point....known only to God and me....I start putting in the beginnings of what will become the edge. I continue in this manner until the bevel is well defined, and then leaving about .040", it's back into the forge for the beginning of the HT cycle.

After completeing the HT, it's back to the grinder for the final surfacing treatment, and the final edge sharpening which is done by grinding perpendicular to the length of the blade. It's at this point that I usually stop, and color it done except for the handle, but if I wanted to continue with more refinement and hand sand it to a better finish, I am unsure of the proper technique. I have done some of this by wrapping sandpaper around a thin piece of steel and "draw filing" as before along the length of the blade. Is this correct, or is there another "preferred" technique. Should a lubricant be used when hand sanding, and what type should be used? I will admit that this step is , for me, somewhat tedious, but it does improve the look of things. I am not interested in achieving a "mirror" finish, but I do like the appearance of a nice "satin" finish with no visable scratches greater than those produced by the final grit, which for me will probably be 600 grit, possibly finer.

[Ray Rogers]

It's sounds like you have a method that works for you and any method that works is fine. The one part I would recommend you change would be the sharpening of the blade before you put the handle on. Sharpening should be the absolute last step in finishing a knife, to do otherwise is to risk serious injury. I realize this would bean you would probably have to change the method of sharpening because the handle and guard might interfere with perpendicular grinding but that shouldn't be a big issue. I sharpen mine on the grinder too, I just treat the platen like a stone (with a moving surface) and run the blade across it edge down.

As for the finishing, the method you describe is probably the most popular. Whether or not to use lubricant depends, at least in part, on the type of sandpaper you use. Lubricant is never required but the finish will often look better if you squirt a little WD-40 on it as you work. When doing the last part of the final finish, sand in one direction only. If you get to very fine papers some day, like 1000 grit, take only one stroke with that piece and discard it.

There are other ways to do this same job. Sometimes, I have used EDM stones for part of the work instead of sandpaper. I imagine someone will come along with more variations beforethis day is out ...

[Kostoglotov]

Finishing like everything else is finding the right combo that works for you. A couple/few things to think about try.

-Try a softer backing on your sandpaper backer: a piece of leather attached to the steel, a wood paint stirring stick, tongue depressors, etc

-Try different lubricants ? WD-40/Mobile-1/Windex/Baby oil. You?ll stumble on a combo with a particular brand of paper that works best for you

-Try some stones. The stones will show you pretty quickly what you think is flat Vs what is flat. Getting a good flat surface will make hand sanding go much quicker.

-When hand sanding or using stones, rotate 90 degrees between grits

-Cheap wet/dry paper typically isn?t very good especially in anything above 240 grit.