Calculating steel

billyO

Well-Known Member
Volume = Length x Width x Height.

So if your knife is 1" tall, 8" long and 1/8" thick, you will need at least 1 cubic inch of steel to make this final blade (well, actually more because you will lose some material in the forging process). But it would be a lot easier to forge out the blade from an 8" piece of 1" x 0.125" than 1 inch of 1"square stock, (or 4 inches of 2" x 0.125", etc...)

But this also depends on whether you are doing stock removal or forging, if stock removal, you will need to start with a lot more than forging.
 

52 Ford

Well-Known Member
I'd you're copying a knife...


If you want to get fancy, you can drop the knife in a graduated cylinder, fill it up with water, pull the knife out and measure the change.

Or put the knife on a scale and do the math. Mass to volume.


OR draw it in CAD and extrude it to thickness and look at the material properties - namely volume.

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jmforge

Well-Known Member
One of the first knifemaking DVD's that I bought was the Charles Ochs basic forging video where he made a 7 inch fighter from 52100. He took a 7 inch piece of 1/4 thick bar stock and forged the though tang knife from it. Combination fo thinning a little bit and distal taper made it work.
 

52 Ford

Well-Known Member
One of the first knifemaking DVD's that I bought was the Charles Ochs basic forging video where he made a 7 inch fighter from 52100. He took a 7 inch piece of 1/4 thick bar stock and forged the though tang knife from it. Combination fo thinning a little bit and distal taper made it work.
Every knife I've forged, I didn't measure anything. I figure out the lengths I need to forge and write down the rough numbers. As I forge, I'll mark distances on my anvil face with soapstone.

I forge the blade first on the end of the stock, then start to draw out the tang a little, estimate how much metal I need for the tang, and hot cut my stock off there. Then I forge the tang.

I work almost exclusively from round bar stock. 1/2" being the smallest I think I've made a knife from. Usually 3/4" to 1" bar. Just cause it's what I have on hand. I got a bunch of it a while back (and might be getting more, soon).

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tkroenlein

Well-Known Member
I don't forge a whole lot, but enough to have a plan when I do. I forge 1/4" stock mostly. I figure it it terms of finished dimensions, plus material loss. So if I want an 1/8" thick knife, 1" wide and 10" long,
I'd start with 1/4" thick, 3/4" wide, 6" long, and grind off extra thickness or cut off excess length as needed.
 

Mod

Member
Yep, I look at the steel I am forging, and sort of imagine it all squished into the shape of whatever I’m making, and use that much of it. Very scientific.
Now that’s what I’m talkin about! I knew all that math I took would come in handy. I’ll have to go back and read up because I don’t remember studying the swish factor, must of missed that day. Thank you, sir. Heading to the forge to squish some shit out!! Lol
 

Mod

Member
I don't forge a whole lot, but enough to have a plan when I do. I forge 1/4" stock mostly. I figure it it terms of finished dimensions, plus material loss. So if I want an 1/8" thick knife, 1" wide and 10" long,
I'd start with 1/4" thick, 3/4" wide, 6" long, and grind off extra thickness or cut off excess length as needed.
Thanks
 

Mod

Member
Every knife I've forged, I didn't measure anything. I figure out the lengths I need to forge and write down the rough numbers. As I forge, I'll mark distances on my anvil face with soapstone.

I forge the blade first on the end of the stock, then start to draw out the tang a little, estimate how much metal I need for the tang, and hot cut my stock off there. Then I forge the tang.

I work almost exclusively from round bar stock. 1/2" being the smallest I think I've made a knife from. Usually 3/4" to 1" bar. Just cause it's what I have on hand. I got a bunch of it a while back (and might be getting more, soon).

Sent from my Champion Forge using Tapatalk
Thanks
 

Mod

Member
I'd you're copying a knife...


If you want to get fancy, you can drop the knife in a graduated cylinder, fill it up with water, pull the knife out and measure the change.

Or put the knife on a scale and do the math. Mass to volume.


OR draw it in CAD and extrude it to thickness and look at the material properties - namely volume.

Sent from my Champion Forge using Tapatalk
Thanks
 

Bühlmann

Well-Known Member
Modeling clay is a useful tool in seeing what you can end up with for a given volume of steel stock. You can also "forge" the clay out to plan your heats, and strategy to get your final shape. This is a pretty quick way to learn without the additional time and expense of forging steel and learning the hard way that you didn't start with enough or started with way too much for the blank you are wanting to end up with.
 
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