For a knife newbie like myself, this thread is an eye opener. Mark, really appreciate for your sharing and good luck in your test. Thank you.
Thank you and your welcomed.
Here's my grinding set-up. Mine is a Bader variable speed. With the file guide in place to aid in nice plunges I have gone through all the grits to 400.
This is a good time to talk about "Two-inch-itis". Two-inch-itis is an affliction that befalls the young and the old, male and female knife makers. It is the groove that sometimes occurs two inches away from the plunge line because most of us use two inch wide belt sanders to grind knives. If you use a one inch belt sander you may find yourself coming down with One-inch-itis. You can catch two-inch-itis in a few ways, it usually occurs when we are concentrating on making a good plunge line if we try to plunge straight into the blade. It can also happen if you grind for a while with the belt not centered on the platen. Most of the belt gets warn down except a small band of grit on the edge of the belt. When you center the belt to work on the plunge, that un-warn band of abrasive becomes a high spot that makes a groove across your blade. Another thing that happens is when we have the whole thing almost done and we go back to work on the plunge a little more, if we don't take care to plunge straight in, the high spot of the ricasso causes the blade to cant against the belt causing the tell-tail groove two inches from the plunge line.
It can be difficult to see the groove, or any irregularities in the blade with all the lines running across the blade but as soon as you start to hand sand along the length of the blade they become obvious, if they are there. Its best to go back to the belt sander with a new belt on it and massage out the groove and any other ripples. It's near impossible to hand sand out the groove, you mostly end up with a polished groove.
Dull belts cause divots and you lose your ability to control the grind, so to prevent having to chase divots around, replace the belts when they start to get dull. The best way to prevent two-inch-itis, and to remove it when it happens is keep the blade moving on the belt, don't stay in one place very long at all. It's hard to do when you're working on the plunge but it works better if you plunge in and then work out to the end in one fluid movement.
The tables on most 2 X 72 knife grinders are too small to grind the profile of the blade properly. I made a bigger table by welding a couple of small "C" clamps to a steel plate. It clamps to the tool rest on the Bader.
The large table makes it easy to grind the profiles square and straight on even the biggest knives.
After the profiles are done, I use an adjustable angle rest to grind the false edges. I welded this one up using scrap steel, the angle can be adjusted by loosening a bolt under the table.
This blade is ready for hand sanding.
Normalizing as I described earlier helps prevent warping during heat treating. Sometimes during finish grinding, on the grinder, stresses are relieved that cause the blade to warp, this one warped just the slightest bit. It's not a problem to straighten them up with a manual arbor press without the risk of snapping them when they are deferentially heat treated
This one is sanded just like the others.
Here it is sanded to 800 grit. On the last two grits I make the last strokes straight and deliberate to make a nice uniform, straight scratch pattern. At this point, you have to put paper towel under the blade when you clamp it down to sand it, if you don't, the backer board will scratch the side you just finished.
These three are ready for handles.
In the mean time, it's time to put more trout in the smoker.
More later, thanks for watching.
