|W2 pizza wheel polishing begins
||[Dec. 9th, 2011|12:46 am]
I started in on the first pizza wheel, the largest one, and the one which is made from one of the classic water-hardening steels -- W2. C - .95, Mn - .22, Cr - .15, Cu - .14, Si - .23, V - .19, Mo - .013, Ni - .08. I bought several pounds of it as 2" round stock, two bars of which may end up being rollers in a rolling mill, but one was made into a pizza wheel. A longish writeup of the evening's progress is below the cut.|
On really close examination, I found no cracks, but there was again a bit of a wave on the edge -- the thinnest and weakest place warped a little bit, not enough to require adjustment, just enough that it probably will be slightly noticeable. Also, the center has bulged up, making the bevel from the middle of the blade to the concave instead of the as-ground flat. I took that off first, using the belt grinder for the last time on this wheel to grind the area around the hub flat and even, but not going very deep. High speed hard abrasives, even structured abrasives, tend to smear the surface of steel around, which blurs the patterns and can even render them invisible, something that's happened to me in the past. (If you own one of my tantos that doesn't appear to have a visible hamon, or indeed any knife I've made, please feel free to send it back for a cleaning and polishing.)
From here on out, it's Japanese waterstones. It's going to have to be the Japanese waterstones because I cannot for the life of me find my queer creek waterstone, one of the few natural high-grade coarse waterstones not from Japan. I have a set of natural stones from Japan I've never used,though, and this seemed a good occasion to break them in.
Before I did that, though, I broke out the wet grinder. It's a Makita donut-wheel grinder, with 800, 2000, and 6000 grit waterstones, though for this run I plan on only using the coarse, and will try to do the rest by hand. This is, to my knowledge, the first time anyone has attempted to do a traditional sword polish on a differentially hardened pizza wheel, let's do it right.
So far, before my back had it for the evening, I got one side smoothed past the layer of decarb and about 90% of the way done for base polish, leaving only the other 90% of this side and the entire 300% of the other side. I think the other side will be harder as that's the side the bend dimples in on. I"m going to leave that whole area, about 20 degrees of arc, for last, and see what I can do to minimize waste while cleaning it up. I did spend some time on the coarsest stone, Kongo-Do, artificial but those are better at the coarsest grits. It has a nice enough feel, develops a bit of a mud fairly fast, though I'll probably use a nagura stone on it for a while until it breaks in.
No photos yet, nothing to look at until I get to some higher grits. I want to see this hamon, but I can wait. Or would it be cheating to dunk it some vinegar and etch and see what I got?
Any questions? It's late, I'm tired, and I'm not entirely sure I'm being clear up above.