Help with convexing my knife

cb4life_30

cb4life_30

Basic Member
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Sep 18, 2006
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I have recently tried convexing the edge on my knife. The knife slices fine but doesn't feel sharp and won't shave hair. Am I doing something wrong or is this how a convex edge is supposed to feel. I used a mouse pad and wet dry sandpaper. Am I missing something please help.
 
That's what I did, then I stropped on loaded leather. Scalpel sharp! It's possible your angle is too obtuse or you didn't remove enough metal for the edge to zero. Did you create a burr, then remove it?
 
What did you use inbetween the 800 and 1500? Or did you go straight from one to the other.

Progression through the grades of sandpaper is important. Skipping too many grades at once will leave your edge jagged and rough because the the grade you're using won;t eliminate the scratches from the previous grade.

You might have done this, I don;t know.....but if it were me and I started at 800, I would go 1000, 1200, then 1500. Of course, depending on the steel and how much of the blade I was going to work on, I think I might have started at 320 or 400 and worked my way up to about 1200.
 
Thanks for the help. I am doing my RAT3 in D2. I am going to try a courser grit like 320 and progress to 600 then 800 then 1500 and finsh on cardboard.
 
I went from 220 to 1000. That was all the store had at the time. Though it was quite a jump and took a long time, it worked fine for me. I just had to remove the burr between grits on a benchstone, and strop it forever. I'm definitely getting some intermediate grits to make my life easier!

BTW. Cardboard is a big jump from sandpaper, though it works. Finish on loaded leather if you can.
 
cb4life_30 said:
Thanks for the help. I am doing my RAT3 in D2. I am going to try a courser grit like 320 and progress to 600 then 800 then 1500 and finsh on cardboard.
Click to expand...

In the end it's your call of course, but I would still recommend at least one grade between 800 and 1500, such as 1200. In fact, I would stop at 1200 for D2, then go to a strop.

At 1500 (having done your previous grades correctly), you will have acheived a mirror polish. You won't see it because the edge is so thin, but it will be (literally) like a mirror (or the beginning stages of acheiving a true mirror polish). I'm not an expert, just a layman, but from what I've read from the Forum's "experts", I don;t think D2 needs to be taken to such a fine edge.
 
Thanks for the help I will let you know how it turns out. I made the jumps because these were the grits available at the time thanks again...
 
Well after messing around with all the different grits. I finally got got it right, sort of. I guess you could say I cheated a little bit. I rapped the sandpaper loosely around a lansky sharpening rod and clamped my knife into the system. Then using a pulling motion I began to develop the edge (setting the angle at 17 degrees). Before proceeding to the next grit of paper I used the fine diamond hone set at 30 degrees to remove the burr. I repeated this process at 600 and 800. I finished by stopping on an old leather belt charged with stropping paste. Don't ask what kind because it was in a plain white tube with a yellow stripe. Anyhow I duplicated the process on my model 1 only I start at 600 and finished with eight following up on the strop. Both knives are now hair popping sharp. Just for fun I stropped my SAK farmer which is still fairly new and sharp. I am happy to report that it is now scares the hairs of my arm. Thanks to everyone for your suggestions especially about using a stone to knock the burr off between grits. I don't know if I still acheived a true convex edge but what ever I did got these knives razor sharp.
 
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