Grind Angle of Chisel Ground Knives

[me2]

Any ideas on what angle is used on the primary edges? I want to make something in the Phil Hartsfield style. Profile pictures of his knives show pretty wide bevels, but the thickness is not always known. I was thinking of starting about 25 to 30 degrees.

 

[brets-ftw]

he didnt actually measure any of his grinds, he said he just did it by eye so that sounds like as good an angle as any

 

[Leu Custom]

15-25 degrees or so depending on the stock thickness and how wide you wanted the bevel to be. It's simple trigonometry.

find your percentage of width bevel to you thickness of blade

so something for instance that is 3/4" wide (bevel) on a 3/8" thick blade chisel grind is .375/.75 = .50

then you do inverse tangent of .5 which leads you to something like 26.57 degrees the blade was ground at. tan-1(.5) = 26.56

I want to say that most of his blades were done from 15 to 20 degrees for a chisel grind.

you can figure out the angle that he used based on the width of the bevel to the thickness of the blade as I mentioned above.

30 degrees will still cut, but it's getting up there.

he used several angles by looking at his blade bevel widths.

FYI: PHILL HARTSFIELD with 2 L's was the father who started it all. PHIL HARTSFIELD with one L is his Son who is continuing his father's legacy!

Hartsfield used 1/16", 3/16" 1/4" and 3/8" thickness tool steel as standard. i'm sure he used odd ball in the middle sizes as well. most famous are 1/8" and 1/4"

 

[me2]

My current plan is a 25 degree bevel on 3/32 stock, prehardened M2. I've made one other blade with this steel and love it, though I messed up on the handle profile and have not been able to find a handle design I really like. I'm torn between a traditional tanto outline and a 10" blade bowie. Either will have black and tan wrapped leather handles. I toyed with angles as high as 45, but that wouldn't cut very well IMO. 20 degrees sounds thin for the kind of things I want to do, like cutting free hanging rope, maybe some 2x4 chopping, rolled paper tube cutting, soda bottle cutting, etc.

The first knife was double beveled, 0.055" thick and single handedly raised the bar for what I expect a knife to do. I filled a laundry basket half full of cardboard cut into 1" x 6" strips and it would still cut a folded piece of notebook paper in two, with the paper folded and standing on the corner of a table. The paper was from a pocket notebook.

 

[Leu Custom]

i'd go with a 20 degree for 3/32". it's so thin that the bevel is not going to be very wide at a 25 degree angle.

all these blades for instance are ground at 20 degrees

the one in the middle is 3/8" stock and all are chisel grind. the top and bottom are 1/8" stock. The top blade is 1" wide so you can see what a
20 degree angle chisel grind will do.

this is back in the day when I used to sign my name with the PL mark

 

[me2]

That 3/8" thick piece looks awesome. I'll probably start at 25ish, and go lower if it holds up and I want more cutting ability. I can always lower the angle, but raising it, not so much. My idea for the tanto is a blade about 1" wide. If I do the bowie, it will be about 1.5" wide. Admittedly, the bowie will look odd with a 10" x 1.5" blade with only a 1/4" wide bevel, but these will be just for me to hack around with in the back and scare the sex offender living across the street.

Since I'm asking questions, what is the finish of the various parts of those knives, like the flats, the edge, and the spine bevels?

 

[Leu Custom]

Since I'm asking questions, what is the finish of the various parts of those knives, like the flats, the edge, and the spine bevels?

The finish on the flats is post heat treatment where I run a worn 40 grit over the flats to remove the discoloration from heat treat. I generally use a fresh 40 grit belt to finish up the bevels and then polish the entire bevel to 320 grit on a 10" sewn concentric cotton wheel. The swedge on the spine bevel is ground in using a worn 80 grit belt on my edge sander (ghetto RIDGID Edge sander meant for sanding wood) but it holds up to metal because i'm using a Norton Alumina Zirconia belt 4x24"....one of these days i'll pick up a horizontal grinder from Beamount Metal works.....a little pricey at probably over $1500 shipped! The Ridgid was only $200.

if you have any questions, feel free to drop me an email at pohanleu@hotmail.com