Edge problem with 154CM

H

Hunterarrow

BANNED
Joined
Feb 19, 2013
Messages
49
Hi. My first post here. I made a pairing knife with 154cm, chisel grind, edge angle is 9.22 degrees. My edge rolls when I cut things on a hard surface like ceramic plates. I have a sneaking suspicion that it could be the poor heat treating but I don't have much experience with this steel. Is 9 degrees too small for 154cm? Thanks.
 
There are alot of questions here, 9 is very narrow but should it roll?? Who did the HT, any info on if it was sucessful? Overheat when grinding? Are you sure the edge is rolling and its not a burr that is folding over. I would not expect 9 degrees to result in a durable edge but I would not expect it to roll over.
 
I don't know anything about 154cm but I do know that if you cut on a ceramic plate you will dull your knife much faster than on a cutting board.
 
It could be the heat treat. I have always sent my ATS-34, 154CM, etc. blades to Paul Bos heat treating. They have the expertese and equiptment to do the job right. They check each blade for RC hardness before it is mailed back.
Some heat treat these steels themselves. I prefer to let the experts do it.
 
9 is much to acute. on my straight razors i shoot for 17-19 total degrees and there are not many edges that are more fragile in use then a razor blade (even running your finger side ways across the edge will make it unsuitable for shaving )
cutting on the plate will kill even a 30 degree total degree edge
the finest i have taken edges for any kind of reall use is about 14 total
 
I sent it to Texas Knifemaker's Supply for heat treat. I'm sure it's the edge rolling and not a burr folding. I may or may not have overheated the blade after the heat treat. I don't think I did but it's impossible to know for sure.
 
you could hand grind the bevel on a stone and try again if you really want to know if you over heated it. Also what rockwell did you heat to?
 
Even with a chisel grind, you will need a secondary angle at the edge for a kitchen knife. Grind a 15-20 degree secondary on it and I suspect the problem will go away. Also, how thin did you make the edge before HT. If it was too thin, it may have been affected. Try grinding it back a mm and then putting on the secondary bevel.
 
yep too thin grind it back a bit to get to the good steel (even well heat treated ther will be a bit of "skin" to grind off)
 
Thanks for the great advice. I didn't think the pre-HT edge thickness would make a difference in the quality of the finished edge as long as it was thick enough to not warp. What would be the smallest thickness of the edge I can put before HT without worrying about compromising the quality of the finished edge?
 
.030" is fine for 154CM. I often go to .010" pre-HT.

The edge should be ground clean of all decarb and expose new steel regardless of how good the HT was. I usually make the blade width about .100" wider than desired, and grind back the edge after HT, then finish the bevels, then put on the final edge.

As I said earlier, I think part of the problem is an edge far too acute. Try grinding it back a tad (.100-.150") and then putting on a new secondary edge angle.
 
bladsmth said:
.030" is fine for 154CM. I often go to .010" pre-HT.

The edge should be ground clean of all decarb and expose new steel regardless of how good the HT was. I usually make the blade width about .100" wider than desired, and grind back the edge after HT, then finish the bevels, then put on the final edge.

As I said earlier, I think part of the problem is an edge far too acute. Try grinding it back a tad (.100-.150") and then putting on a new secondary edge angle.
Click to expand...

I was pondering something like this the other day, thanks for the tip!
 
Last edited:
I put a secondary and the edge holds better though not as sharp. I guess cutting on a ceramic plate didn't help either. I tested other knives and their edges rolled too. Thin edge + chisel grind + ceramic plate = ruined edge lol. Thanks for the good info.
 
Last edited:
You must log in or register to reply here.
Back
Top