The results of my latest flex test are?

Kevin R. Cashen said:
Gentlemen, we are still chasing our tales with heat treating in a area that does't care about our heat treatment. Prybars are thick, I have half a dozen metal rulers floating around my shop, although right in front of me they have never crossed my mind yet when looking for something to pry with. I do have have the utmost confidence they would not break, but anything beyond a couple pounds would be imovable to them. However any 5/16" thick piece of steel laying around, regardless of heat treatment will work infinitely better. Crowbars have no fancy heat treatment they are just thicker or have geometries that allow them to exert more force without yeilding. Any steel will bend well before it breaks when deflected but how many prybars have you owned that bent very often in use?

On a humerous side note; several years back at Ashokan I cut a 1" free hanging rope with a prybar in my lecture:) The crowd seemed to like it. Some thought it was silly at the time, but I told them if knives are for prying why couldn't I cut rope with a Chinese prybar?;)
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Did you sharpen it, or just get it movin' really fast? :D
 
im just now starting to grind out the next Ball bearing blade.
With any luck at all I should be ready to Heat-Treat tonight.

What will I do?
Im still up in the air about some things, but what I think I may do is to do the normal Edge Quench and then do two 450 oven temperings.

I dont plan to test this blade as I really want to move on to make a sheath for it as I plan a few new things for the sheath design.

However the blade I make after this one ,I think that blade I may do the same type of flex/bend tests to see how Im doing and if I am getting the results I aim for.
People ask me about doing cutting tests, but Im not sure I really know of one thats like a "Univeral Standard"...cutting rope is suggested, but thats a bit hit and miss.

Another thing I question about doing a cutting test is, am I testing the blade steel or am I testing my ability to sharpen a knife?
 
When you're using the torque wrench to bend your blade, you're not actually applying "torque" to the blade. Torque is twisting force applied along the axis of the metal, like turning a nut or screw. When you bend a knife blade, you are applying compression force to one side of the steel ( the inside of the bend), and tensile force to the other side. I suspect that shear may be a factor in the bend as well, because of the opposing tensile/compression forces, but that is beyond the scope of my learning at this point. A more accurate repesentation of shear would be if you were to place a bar of steel perpendicular against the blade right at the jaws of the vise, then struck the other end of the bar, or otherwise applied pressure. A materials shear strength tends to run around 40% of it tensile strength.

The four types of stress on materials:

Tension - stretches
Compression - shrinks
Shear - shifts or cuts
Torque - twists

Not that this addresses your issues directly Alan, but I noticed the terms being bandied about and thought some clarification was warranted.
 
Phillip Patton said:
Did you sharpen it, or just get it movin' really fast? :D
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It was entirely a prybar still, no forging or shaping, but I did sharpen one edge. This resulted in it being much less usefull (if not even dangerous) as a prybar, but that is what happens when you alter a tool for uses contrary to its intended purpose, sacrifices are made. Specialization vs. generalization.
 
Mike Arsenault said:
The four types of stress on materials:

Tension - stretches
Compression - shrinks
Shear - shifts or cuts
Torque - twists

Not that this addresses your issues directly Alan, but I noticed the terms being bandied about and thought some clarification was warranted.
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there we go :) I said someone would pop up and know more than me :D
 
mrstenoien said:
actually from what i've read japanese katana's broke fairly often
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There was a story that my Kendo teach had me read when I told him I was interested in learning to forge the katana.

The story was about a blade smith who made all the weapoins for his master's troops.
Before each battle he and his sons would line up to wish the master and his men well in the war.
After the war he and his sons would run out to meet the returning troops.

It was after one war that he noticed that none of the troops would look at him in the eye as they passed by. Even the master turned his head when he passed by.

This was important, and so the troubled bladesmith questioned what would cause the men to avoid him so?

What he noticed is that almost all the troops were returning with snapped blades in their hands....his blades...

The bladesmith knew his life was on the line and so he shut himself and his sons in their shop for 40 days while they worked and worked on the creation of a new type of katana that would not snap so easy in war..

The next time his master led his troops out to make war they all were given this new designed sword.

After the battle the troops returned from victory and lifted the old bladesmith up and carried him around in dance.
 
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