Edge Retention/Rolling Test Stand

[me2]

Scott, didn't you do something similar for impact testing of A2 a while ago?

[scott.livesey]

this tester should show how the edge deforms when testing very hard(Rc65+) vs. not so hard(Rc55). it should easily show edge deformation caused by cutting board media. since the only variable is weight, I should have the same results as you.
thanks for taking the time to develop this testing idea.

[scott.livesey]

Scott, didn't you do something similar for impact testing of A2 a while ago?

sorta, but not this controlled.  we had a conveyor system that moved 3 to 4 pound steel parts.  there were places where impacts happened each cycle.  parts made of A2 chipped and cracked.  parts made of H13 or 4240 dented or rolled.  what it showed was A2 is not the magical do everything steel some engineers believe.

[grepper]

Would it make more sense to lower the "strip of steel" onto the blade? That way the weight of the knife would not have to be taken into consideration. Additionally, it would simplify construction of the stand, and make it so it could be placed over any device folks had lying round that could clamp a blade.

The only thing I don't like about that idea is having blades clamped edge up on a work surface increased the likelihood of injury.

[EOU]

It's a thought. Obviously edge up doesn't scare us. We're the guys who introduced the KN100 as our first edge sharpness test instrument.

[EOU]

Well it pays to know people who know something. Ken first suggested the similarity of our proposed new test stand to the original KN100 and Grepper suggested placing the blade edge up. It took awhile to sink in but we think it may be time to rethink how the test stand should be built. The proposed existing design is, in fact, very much like our first analog edge tester, the KN100. So much so, now, that we think that it might be best to modify the KN100 design into our edge structural test stand. 

   

Here's why:
We already have the frame of the KN100 in inventory. We only need to modify the piston assembly into a structural tester as opposed to an edge sharpness tester. The current 5/16" diameter piston rod tube would be replaced with a HRC65 hardened rod of the same diameter. The end of the hardened rod will replace the 1/4" wide hardened strip we anticipated in the first design. We'll grind a very shallow (.015") and narrow (.0625") groove in the end of the rod so that it can be positioned on/over the knife edge in a  repeatable fashion. In practice the piston rod would be lowered onto the edge and then the prescribed amount of weight added to the piston platen. We'll use the ME110 vise (magnetic base) to hold the blade in the edge up position while the test is being conducted. 

   


Personally, we favor the dedicated design as first proposed even though we have no reason to believe that the modified KN100 design would deliver any less accurate information.   Here is a really good reason to make the switch though. We will be able to produce, package and ship 5 modified KN100's as cheaply as 1 of the original design. This means that rather than you shipping us edges for test we will be able to ship you structural testers and you'll be able to conduct your own tests. We'd be happy to donate four or five of these units to the cause. The only thing you'll need to have on hand is an edge to test and an edge sharpness tester. We can then all report our edge test results back to the group for comparison and discussion. 

We'll have to arrive at an agreed test protocol and then we'll be off. So what do you think about this shift in the wind?

[Mark Reich]

Wise use of excellent resources = successful mission.  

[grepper]

I like the idea of using the piston itself instead of a separate steel strip.  It makes the overall design simpler as well as easier to design and less time consuming to assemble.  Mr. EOU had his thinking cap on when he thought of that idea.

   

[Ken S]

This exchange reminds me of the Borg on StarTrek; there is much mental power in the combined minds of the collective.

Ken

[Bubby]

I'm with Ken. Resistance is futile. I'm throwing my hat in the ring for a test stand. I have an edge sharpness tester and I have an edge, maybe six that i'd like to test.