Flexible Filleting Knife

[Jim T]

I?ve had a request for a filleting knife about 13 inches in overall length. I know most fishermen like to have some flex in the blade when they use this kind of knife so here are a few questions?.

- Is ATS-34 or CPM154 a good choice for this kind of knife blade?
- Is 1/8? thickness good enough for a blade this length? Or should I look at something thicker? Thinner?
- Will proper heat treating ensure some flexibility without sacrificing the tensile strength of the steel?

Jim

[Ray Rogers]

I make 11" fillet knives from 3/32" stainless, CPM 154 seems like a good choice, I'd stay away from ATS-34. However, stainless steel does not flex like carbon steel so anyone looking for a blade that flexes like a Rapala better stay with carbon steel.

Further, the key to making a stainless blade flex is more about the geometry of the blade than the heat treatment. The HT is important, of course, but as long as it isn't rock hard it can be made to flex by controlling the profile and distal taper. Think 'more steel, less flex' and grind it thin where you want it to flex. The trick is to not let the profile get too narrow for the length, otherwise the blade can twist during a cut where a lot of flex is used...

[Jim T]

Wow, thanks Ray! Didn't realize that stainless steel had less flex than carbon steel.

Is ATS-34 significantly different than CPM154? I'm just curious as to what advantage CPM154 has over ATS-34 when it comes to fashioning a filleting knife. I thought their chemical compositions were nearly identical.

Jim

[DaveL]

Actually I made these with Jimmy Lile and we used 440C but did have a few in D2. Go figure but they worked...

[Ray Rogers]

ATS-34 is supposed to be about the same but a few years back a few of us started having troubles with ATS-34. Blades were breaking and HT seemed to be off from the way it used to work. In the end, since there were so many alternate choices for ATS-34 many of us decided to avoid the potential problems and just use the other steels. So, ATS-34 should work just fine but I figured to steer you away from a potential problem which may or may not exist anymore ....

[Jim T]

Thanks Ray. I'm trying some CPM 154 now.

If I wanted to try to make a filletiing knife from carbon steel (as opposed to stainless), would 0-1 be a decent choice?

Jim

[Jim T]

Dave, did you mean to post pictures with your comment? Or did you just post in the wrong place? I couldn't find any of the images you might have been referring to. I'd love to see what you and Jimmy Lile made with 440C.

Jim

[Ray Rogers]

O1 would be a good choice if you have an electric HT oven. If super springiness is the goal or if no oven is available then consider 5160 if you have the means to thin it down because it's usually available only in 1/4" and thicker bars...

[DaveL]

I do not have any of his fillet knives but we did a lot. The favored steel was 440C but he did mostly D2 and some were made that way. Actually just care will keep D2 looking good. I wish I had pictures of it all but I do not.

By the way, I think if you are thinking of 01, why not do A2 which is just a little more chromium but a very nice edge.