Sword layout

Kevin R. Cashen

Super Moderator
Ever wonder how one keeps a 36"+ grind line straight? Well here is my solution. When I started out in knifemaking I would attend the shows and could spot the stock removal blades instantly by how straight, clean and precisely they were shaped. I always thought how great it would be to make a forged blade with the same crispness. But bladesmiths take that perfectly flat and clean bar of steel that stock removers get to work with and beat the snot out of it, leaving it hammered, all scaled up and with tapers already forged into it. Then I started looking at the flat square area in front of the guard and saw possibilities in the ricasso. After a little tinkering I worked out a way to use it in scribing centerlines using the old layout table favorites the height gauge and surface plate.


It all worked great for knives, but swords posed a few more problems. One needed a really big surface plate and then you need to overcome gravity pulling on a 36+ inch tapered forging. Then one day I found this baby:


swordlayout.jpg



I was so happy when I brought this home but my family simply said “OK, so you have a 5 foot slab of granite.” I built a stand sturdy enough to hold it with leveling units on the bottom and a movable screw hold down. After the ricasso is entirely trued up, the edges of the forging are cleaned up and layout dye applied to them. The next part of this system is on my lab computer in the shop. I built an Excel spread sheet into which all I have to put is the exact thickness of the ricasso in .000” and the thickness I want my edge before heat treatment. The program instantly produces the two settings I will need to set the height gauge to and the exact points on the blade under which I need to place a series of metal shims, that I made just for that purpose, to bring the centerline of the blades cross section up on a plane that is dead level with the top of the surface plate. Then the holding screw is tightened down on the ricasso and all I have to do is slide the preset height gauge along the length of the blade, reset it to the second number and repeat. I will then have two perfectly straight lines to grind to at the edge of the sword. But this is one reason why I am such a critic of overheating steel on the grinder, if you get crazy and warp the blade, your nice straight lines are warped as well.


Anyhow, I used to sit at that surface plate for a long time with a calculator, forgetting and retyping numbers, but then I looked at that spread sheet on my computer and wanted to kick myself for not wising up a long time ago.
 
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KenH

Well-Known Member
Nice table Kevin - I never worried about how ya'll kept grind lines so even..... I knew the answer... MAGIC!!! Got to be magic, only way I can see it working. {grinning}

Ken H>
 

John Wilson

Well-Known Member
Great explanation for offsetting the slope and supporting the sword for a straight centerline. What I don't know is how you can work the sword along its length without flexion causing problems as the blade is worked.
 

KenH

Well-Known Member
What I don't know is how you can work the sword along its length without flexion causing problems as the blade is worked

John, see my post above where I explain how it's done..... MAGIC!!!
 

Kevin R. Cashen

Super Moderator
Great explanation for offsetting the slope and supporting the sword for a straight centerline. What I don't know is how you can work the sword along its length without flexion causing problems as the blade is worked.

Flexion is not a problem, if it truly is only elastic flexing and will return to true when the load is removed, but bending or any permanent deformation is a problem. I apply almost all of my pressure directly over the belt and take it easy not to force things too much. If I do widen my grips and take a sweep I am certain to stay within the elastic limit.
 

John Wilson

Well-Known Member
that makes sense, although I'm quite positive there is a serious amount of experience required to know where that threshold lies.
 

Kevin R. Cashen

Super Moderator
that makes sense, although I'm quite positive there is a serious amount of experience required to know where that threshold lies.

Oh, I'm not going to lie to you, there is a serious and long learning curve to keeping any grind line straight and flat on a 3 foot blade. I advise those lacking any masochistic tendencies to sell hunting knives with only the occasional bowie, and enjoy life;).
 

Smallshop

KNIFE MAKER
"I advise those lacking any masochistic tendencies to sell hunting knives with only the occasional bowie, and enjoy life
wink.png
."

Hahahahaha!!! I think I'll take that advise...lol
 

Smallshop

KNIFE MAKER
DSC01035.jpg

Kevin....as a fellow granite lover you might appreciate this. It was the base for an old Co-ordinate measuring machine...the frame is original though I did cut the over-arm supports off. It has four handy 1/2-13 inserts for light clamping. 22" wide 48" long and almost 7" thick....I kind of know what you went through to get yours home.....I bought this 15 years ago and recently moved it to the "upstairs" part of the shop....it seems heavier every year! But has been indispensable for the years of aerospace work I have had to measure on it. I do not really use it except for layout work now....and very handy for that too. I don't know what it weighs but I can move my Bridgeport easier....
 
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Andre Grobler

Well-Known Member
But how do you know you start with a straight blade? And you do not inadvertently “straighten” a curve or warp with the shims? Not sure that it matters because the only thing you need is it to be anally retentative eyeball straight and you seem to have that in place already
 
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