Thread: grinding sequence?

hi all. I was watching some videos on youtube last night and found one of maestro livi doing a straight stock removal razor where he really went over his grinding sequence. now watching his videos is kind of wild as he must have half a dozen belt grinders, but uses hard wheels {and handheld angle grinders} for most of the grinding work, and then switches to the belts for finish work. but he roughed in the blade on a fairly large hard wheel, down to an edge, and then spoke of a "4 wheel progression" down to an extra hollow grind, using the grind lines from each wheel as a guide for the next wheel's grind. and then once the blade was ground and he had the ridges the way he wanted them, he went to a belt and cleaned the ridges out.

now ive only ground half a dozen razor blades, but this struck me as an excellent way to really control the grind as you bring it down, and to keep everything nice and even. so I went ahead and ordered 3" and 4" wheels for my 3 wheel 2x72 that I built out of a treadmill and old pop cans to try it out. I think it should work much better than hogging with a 5" wheel, and then cutting in and trying to blend with a 2" at the same time.

Originally Posted by caltoncutlery

using the grind lines from each wheel as a guide for the next wheel's grind.

My method utilizes something similar to this. This thread probably should be in the forge sub forum.

blues, on looking at the forums, I think you are right. I guess when I think of a forge sub forum, I'm thinking of forging, and grinding in a workshop. sorry. maybe one of the mods will move it over?

Originally Posted by caltoncutlery

maybe one of the mods will move it over?

Done

thanks mainaman!

Keep in mind that most of us here rock the blade on the wheel to minimize surface heat buildup.
Livi Uses wet wheels so heat isn't an issue and he keeps blades stationary.

But yeah. After heat treatment I grind the blades further using my patented 'foiling the edge' method and set the bevel on a stone. When I know the bevel is ok, I grind the hollows deeper in a similar fashion.

Bruno,

can you give a hint on your foiling the edge method? is it like flexing the edge on your thumbnail to check for thinness and evenness at the same time?

I played with the setting of the bevels to check for evenness to be able to get the edge bevels close. and that seems to work really well. but what I'm wondering about is how to check that the extra hollowing steps after that are nice and even and thin. this whole hollowgrinding thing is pretty new to me. ive only done maybe 8-9 hollow grinds so far, but have done a couple thousand flat and convex grinds on knives. one thing that really helped me out when I started making thin kitchen knives was to check the blade while I was grinding with a micrometer. I set my mic at whatever measurement, lets say .025" then fit the blade between the jaws, and then use the edge of the anvil to lightly scratch a line from the heel to the tip. that line will show where you are thick and thin as it moves along the blade. the biggest problem with that here is that the anvil is 1/4" diameter, and the surface of the blade is curved, so you wouldn't get the same effect.

and maybe just now in typing, I thought of something, maybe taking a set of dial calipers, and regrinding the jaws from flat to more like a pincer sort of thing so they will reach around the curves and ridges in the 4 wheel grind. that would let you check as you are grinding with each wheel, and then blend them all in on a belt. and I think I have an old set of cheap plastic calipers that I will grind down and see if it works the way I think it will.

so I started another couple to practice on and to figure out the grinding sequence.

here they are forged and heat treated



sides flattened and tangs rough tapered



grind hogged out and done one the 6" wheel. coated in layout dye, and a line scribed with the micrometer set at .025"

here is after the 5" wheel, you can see how the scribed line with the mic jaws set at .025" moved higher up the blade, little wobble, but that can get cleaned up now that I know where it is.



now starting with the 2" wheel to continue



final part of roughing in with the round part of the wheels. you can see the scribe line, and the ridge left by the previous wheel.



now smooth out the ridge by running the wheel into the grind, and letting the flat part of the belt clean that ridge



other side of the blade with layout dye. the top scribe line is with the mic set at .025", the bottom is .015"



here is a shot of the spine from the point



all of this grinding was done on a 36 grit belt, so now take it down to a 60 grit really quick, and a fast etch to check the pattern as everyone always likes to get a glimpse of what its going to look like

so now I can go back and clean up the flats and taper on the tang, then go back and clean up the grind, then set the bevels on the stone to double check, and then on to finishing going down through the grits.

I may still grab another mic or set of calipers and mod the jaws so I can measure behind each grinding ridge, but this mic seems to work ok as long as I keep the ridge in mind.

and I cant wait to get the new 3" and 4" wheels to see how they fit into the sequence!

and not sure if this one will turn out as the blade behind the edge is now at about .008" for almost 1/4" back from the edge, but getting the sequence part down is what I'm after right now, so ill probably just take this one down and see what happens. it may find a place next to my sink, or a special place in the trash can.