-
The BladeForums.com 2024 Traditional Knife is available! Price is $250 ea (shipped within CONUS).
Order here: https://www.bladeforums.com/help/2024-traditional/
Fillet Knife Questions
- Thread starter LexEdman
- Start date
- Joined
- May 28, 2013
- Messages
- 232
I'm really new to knifemaking, but I did make a fillet knife out of 01 tool steel. Everything that I read pointed towards the thickness being more of a factor than the hardness when it comes to the flexibility of the blade. I started with 1/16" and thinned it out for better flex. Hope this helps.
- Joined
- May 2, 2013
- Messages
- 1,711
Hopefully Stacy will chime in and tell you exactly, but yes, the thickness is the real consideration with a fillet knife. You should HT and temper just like normal I believe, but want it to be about .080 or so when finished.
- Joined
- Apr 20, 2005
- Messages
- 2,359
Good advice, distal taper and geometry pretty much one and the same thing. I was always
under the assumption that " spring temper" is what I was after. Few knives see the repitition
in cutting that a fillet knife does unless its some sort of testing. I would rather not have to touch
up in the middle of a batch of fish. I want every Rc point I can squelch out of a fillet knife which
at the moment for the steel I'm using is 61-62. I rely on the grind. = distal taper = geometry.
Ken.
under the assumption that " spring temper" is what I was after. Few knives see the repitition
in cutting that a fillet knife does unless its some sort of testing. I would rather not have to touch
up in the middle of a batch of fish. I want every Rc point I can squelch out of a fillet knife which
at the moment for the steel I'm using is 61-62. I rely on the grind. = distal taper = geometry.
Ken.
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Aug 20, 2004
- Messages
- 38,513
Flex is a product of thickness, not hardness. A piece of steel will flex the same amount at Rc 50 as it will at Rc 65. The difference is that when the elastic limit is reached, one will take a set (bend permanently), and the other will break.
Fillet knives generally need to be thin. I use .065" stock for most of mine. They flex a lot. I use .100" stock to make a "stiffer" knife. I haven't used .120" stock for a fillet knife in many years....since I got tired of grinding it down to half its thickness. Mainly I use CPM-S35VN for these knives and HT to Rc 61-62. The get wicked sharp, the edge last well, and it isn't insanely difficult to resharpen.
Fillet knives are not intended to cut hard things, just flesh and soft bones. They are generally made around Rc 62. , The bevel should be a FFG ( full flat grind) to a near zero edge, with a fairly acute secondary added to that. I do the secondary around 10° . The amount of distal taper will control how much more the tip flexes than the blade's main body. A very thin tip will curve around ribs in filleting flounder, and a stiffer blade can be used to peel skin off a rockfish.
Since these blades are thin to start with, the average is about a 25% distal taper. If you are working from thicker stock, I would suggest 50%. BTW, I measure the distal taper 1" back from the tip.
I used to grind the blades and do the HT. Now I profile them, drill any holes, and send them to Peters in batches. I do the bevels after HT. I quit grinding at 220 most times, but on smaller blades, go to 400 grit. I sharpen the edge on a 400 grit belt. The satin grind looks good, and seems to be fitting for a working blade.
ADDED:
"Spring Temper" is a lower hardness, not a higher one. In making springs, they need to be able to flex farther without breaking. Thus they are tempered at a higher temper than a blade will be.
Fillet knives generally need to be thin. I use .065" stock for most of mine. They flex a lot. I use .100" stock to make a "stiffer" knife. I haven't used .120" stock for a fillet knife in many years....since I got tired of grinding it down to half its thickness. Mainly I use CPM-S35VN for these knives and HT to Rc 61-62. The get wicked sharp, the edge last well, and it isn't insanely difficult to resharpen.
Fillet knives are not intended to cut hard things, just flesh and soft bones. They are generally made around Rc 62. , The bevel should be a FFG ( full flat grind) to a near zero edge, with a fairly acute secondary added to that. I do the secondary around 10° . The amount of distal taper will control how much more the tip flexes than the blade's main body. A very thin tip will curve around ribs in filleting flounder, and a stiffer blade can be used to peel skin off a rockfish.
Since these blades are thin to start with, the average is about a 25% distal taper. If you are working from thicker stock, I would suggest 50%. BTW, I measure the distal taper 1" back from the tip.
I used to grind the blades and do the HT. Now I profile them, drill any holes, and send them to Peters in batches. I do the bevels after HT. I quit grinding at 220 most times, but on smaller blades, go to 400 grit. I sharpen the edge on a 400 grit belt. The satin grind looks good, and seems to be fitting for a working blade.
ADDED:
"Spring Temper" is a lower hardness, not a higher one. In making springs, they need to be able to flex farther without breaking. Thus they are tempered at a higher temper than a blade will be.