Thread: I’m not getting straight edge.

Hey everyone. New member and a little late to this thread. But I’m currently working on my first few kamisori style razors. I don’t have many tools but I’m a tool sharpener and have access to a few good ones at work. Best tool I have for what I want is a tormek T8. I’ve been cutting out my blanks from 1075 with an angle grinder and cut off wheel, shaping them on a big bench grinder refining it with our little belt grinder, mark out a centre line on the edge then it’s to the tormek to profile it. I pretty much start in the centre of the blade on the omote side and i can give the omote a full hollow (very slight with the 10” grindstone) then I give the Ura an aggressive 1/2-3/4 hollow until i reach the centreline. Blah blah blah heat treat in my propane forge. Temper in a crappy oven. Touch up the omote and grind the Ura to zero (until I get a burr on the omote) here’s where I want some advice. I’m not getting straight edge. The centre always comes up first and the tip and heel are always a little thicker. When grinding it should I rock from heel to tip? Would that make it wavy and uneven? Thanks in advance and sorry for the rant!

You post was moved here Luke, to better help you get some answers.

Just a SWAG. There is a tendency in grinding on a wheel to move a blade back and forth. If the wheel is flat dressed, the effect is that the center of the blade spends more time on the stone than the ends. I found that out even with a 4" wide stone. Now when i use that grinder, I make passes across the whole length of the blade and off the tip end. Yup, a bit of a trick to keep the same pressure at the blade contact point. Can be done though.
Think of time on the stone at a given blade location if that helps understand the idea. Sorta like honing a 'frown" out of a blade. Do a search for frown here.

Good luck, I honor your dedication.
~Richard

In addition to the previous answers: when I am grinding a razor, I regularly put the razor on a flat surface and see if there are sections that need more metal removed. This makes it easier to get a good edge at the end.

could also be your presentation of the blade to the grinder. if you always present the same spot to the belt when you start, then it will get more grinding time than the rest of the blade.

also whatever spot you present to the grinder will almost always get a fraction of a second more time as the blade settles to the belt.

Thanks CaltonCutlery that makes heaps of sense thinking back to it! I think not dressing the stone flat often enough would have been a factor too! Next time I’ll do better!

Update. I’ll be working on a second razor tonight. I’ve put a smile in the blank hoping it’ll either work itself straight or be a slight smiling blade. Ive also convinced my boss who lets me take the Tormek home on weekends to work on my razors to buy a 4000 grit stone. Hopefully it’ll polish up the blade real nice and make it wicked sharp. Also our diamond abrasive supplier at work has .5 micron paste for stropping which I’ll get for my kangaroo strop

Nice looking fixed blades.

I think anyone who has spent time on the grinder has done this. When you are in contact with the wheel or belt, left to right or right to left, NEVER back and forth. If you go back and forth, the center spends more time on the wheel and gets more material removed.

I have recovered from that by making a "jig or round wooden block out of a 2x4" to the same diameter as your wheel and 2x the length of your cutting edge. Cover jig with sandpaper and continue your hollow by a pulling and pushing motion, parallel to your cutting edge. This will remove material at your high spots.

I agree with Scott, good advice.