Out of curiosity: 90 bend?

T

TLM

Joined
Jan 11, 2000
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I read the requirements for ABS journeyman test, they have propably been discussed many times over in this forum so no more generally:p

The 90 degree bend test does not specify the thickness of the blade or for that matter the length thickness ratio used. There is very strong geometrical element in this test (thickness squered) how is this taken into consideration, it means that if you make avery thin (and/orlong) blade it will pass this part easily. The knife in question will not be a very practical one. An other cheat might be to thin the blade closer to handle, this way you still retain chopping capability. Comments?

Living on this side of the pond I am unlikely ever to take the test.

Tapio Manner
 
I think you've already got it all figured out Tapio. The test isn't for the blade as much as for the skill of the smith taking the test. So the object is to forge up a blade with a nice, smooth distal taper with the proper heat treating techniques, and the proper steel. So the blade has to conform to the test criteria or it will most likely fail. It's all about blade geometry and heat treating. The goal isn't to cheat your way to a passed blade/test. It's to come up with a blade that will bend like a blade of grass in the wind. That takes skill and mastery of your craft. I had a problem with it in the beginning but now I understand. Hope this helps.
 
The JS test blade needs to be about 2 inches wide and 10" long with a distal taper from the handle to the tip. It has to be inspected by the master smith before performing the tests. It could be a reletively thin blade but needs the differential heat-treament to pass the bending test. The bend should be a gentle sweep instead of an abrupt right angle near the handle. Its not as easy as one might think to pass the chopping test and then the bending test unless the heat-treat is correct.
 
Max and Bruce both have the concept. Each of the ABS tests, alone and by themselves really don't prove much. But when you put all three together, it proves that the bladesmith grasps the overall concept of blade geometry, along with the heat treat, along with the proper grind which enables the blade to be thin and sharp enough to cut the rope.............durable enough to chop the 2x4s, and tough enough to withstand the bend test. The distal taper as mentioned before, along with the edge hardening, will enable the blade to distribute the stress of the bend along a wider arc, whereas a blade with not enough distal taper will concentrate the stresses in a small area and more times than not, the blade will break or crack beyond 1/2 the width. Both of these spell failure for either the JS or the MS test.
 
Tapio; Ed, Bruce and Max are giving you the straight story. Though it sounds easy, it is a little harder than it looks. If not then your accomplishments as a bladesmith have taken you above this level and you are to be commended for your skills. The physical test is only a test of your forging and heat-treating skills, not a test for the perfect blade. The Mastersmith administering the test will be quite observant, if he thinks you are working one part of your blade to the exclusion of another part of the blade he may ask you to cut again. It is within his discretion. And really; to try to "cheat" on anything is to actually cheat yourself. The ABS has rated smiths from several countries, right off the top of my head ; Canada. France, England, Australia, Japan and I probably left out some. On a closing note; if you do test one day, the physical part of the tests are the easy part. The judging board on your five submitted knives are quite serious in their efforts. Your work must be up to par. mw
 
Thanks to all for answers. I may have put my question a bit unclearly. I questioned the test set-up, blade thickness has a stronger influence than material breaking strength because it affects the result in squered form. Also if you are using a tube to bend the knife the longer the better because that way the bending point moment component becomes larger relative to shear component and point moments induce naturally a smooth circle, shear force has its maximum bending at the fixing point.

As a use oriented test I like it but the test set-up maybe has a few holes. It propably is a more usefull test than the technical alternative of measuring hardnesses, yield and breaking strengths.

Tapio Manner

More of a user than builder kind, I do have a few projects waiting...
 
Tapio, i think that you don't get the point. You have to make ONE blade that has to pass ALL THREE tests AND meets the size requirements of the ABS which are maximum blade length of 10" and maximum blade width of 2". This all together makes the test difficult to pass for a beginning bladesmith.

Achim
 
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