The long pause was no pause at all. I worked on the blade every evening and but I could not give it more than half an hour to one hour a day, so the progress at this stage was very, very slow.
After the hardening came tempering, which is rather easy and dull process. I wanted the blade to be primarily tough, not overtly hard, so I gave it two half hour courses at 200 °C in the baking oven. This has removed a lot of the hardness and almost all of the brittleness. It should be easy to sharpen and maintain sharp but it should not snap when hitting something hard. With a kitchen knife I would lower the temperature to 150 °C or perhaps perform differential tempering.
Next step is polishing. This is by far the most time-consuming and dull part of making a knife. Here are all the belts on my belt hanger. Before hardening I went all the way from left where the pink ceramics belts are (P40-P120) through middle blue-green zircon-corund (P120-P320). After hardening I gave it one more pass with zircon-corund P320. Very thorough pass, because the blade was slightly pitted from the failed hardening attempts. After that came the last third of the belts, which are Trizact belts (A65-A6, which is equivalent of P300 to P2500). There are six Trizact belts, and each took approximately one hour. Had I more experience I could perhaps speed it up by 30-40%, but it would still be a lot of time – I want the blade to be as near perfect as I am able to make it. So at each stage it is important to remove absolutely all scratches made by previous belt.
Of course thick blue marker helps here as well, because otherwise I could get easily confused about which facet I am working on. As I learned when doing my previous dagger. To be able to see the marks from previous grind, one does alternate the angle – that is for this facet for example I was grinding diagonally with the point down, so next step will be with point up. Were the facets perfectly straight and not wobbly at all from the beginning, the process would be fast. Alas they were wobbly and I made them wobbly in the process in decreasing degree of wobbliness untill I reached nearly straight towards the end. What I learned here is that I really, really need speed control for my belt grinder, because during polishing slower speed of the belt would speed up the work – I would get better control of the blade and most importantly, the edges of the belt would not make divets and scratches so fast as they do. However even as it is it is working well, but requires a lot of skill that I do not yet have. A lot of eyeballing was involved.
Today I finished on the grinder but I am still not done. For a mirror-finish more work is needed. Kitchen knife would get a few passes on a buffing wheel at this point and that would be it. That would give it nice mirror finish but the scratches from the trizact belts would still be somewhat visible. For this one though now comes excessive use of elbow grease. I will work my way through a series of wet polishing papers P2500 all the way to P7000. For this I use my trusted gizmo that has seen me through multiple blades already. A piece of hardwood board held in a vice, with leather strap glued on it. On the leather I can lay a strip of sandpaper. Sometimes I rely on the adhesion between the wet leather and the sandpaper to hold it in place, sometimes I hold the paper in place with the help of two springs and something made from fence wire I cannot put a name to.
After that I will be done with this phase and I will be able to perform the last step in making a blade – signing it.
I still have not resolved how to do that. I used to have my own maker’s mark consisting of my stylized initials. It was very easy to etch or engrave and I would love to continue to use it. But by purest of coincidences that very same mark was a few years later independently designed as Bluetooth logo. We’ll see what I come up with.