Need help determining a standered for test cutting machine

N

noss4

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Jul 7, 2006
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Hello,
I built a test cutting machine to perform cutting tests on 3/8" Manila rope.

It is not finished yet. I will be adding a digital scale and a Linear Actuator to apply weight/pressure in the next few days.

The SOG seal 2000 is mounted in the machine. I will test both the plain edge and the serrations.

I need some of your expertise to come up with a standard. ( weight- number of cuts push and pull etc.)

I will video tape the entire test for all to see.

Thanks for your help.

I mistyped standard in the title so please no attacks on this. I am fully aware of this but I'm unable to correct it.

Below is a photo of the machine.


obj481geo360pg21p9.jpg
 
Maybe the question should be first asked, what kind of cutting tests?

How long will it cut through rope at x weight?
 
DaveH said:
Maybe the question should be first asked, what kind of cutting tests?

How long will it cut through rope at x weight?
Click to expand...



I was thinking of how many strokes x weight it would take to cut 3/8" Manila rope. Time could also be a factor. This is what I would like to know from you guys.

What would be the appropriate standard ?

Voppa: Thanks, it was fun to build.
 
William. M: I figured I would start out low, cut and build up as necessary.

This is what I want a community opinion on. Should I set a weight and cut or
start low then add ? how many cuts each time ? etc.

The machine is controlled by a computer so the number of cuts can be set for
whatever is the best number ?
 
You need to ask someone with a degree in Physics for sure'''

Looking forward to these results
 
well....thats the coolest tool I have seen in a long time ...

But, well, Im not sure how usefull it will prove to be.
It may work, but it seems like you are going to a LOT of trouble to find an answer you could have learned all by yourself....

Im just not sure...
 
Now this would be a "test".

Graph the results - on Y axis plot the force required to cut, and on the X axis plot number of cuts. This will give good illustration of edge retention, especially when compared to other knives that received the same test on the same testing equipment. You should think about some method of checking your equipment as well. I think I'd start with a second scale (for a back up and check for the first scale), and an object to use to verify the weight measured on the scale is consistent (get a 5 lb rock, and use that rock before every test to make sure the same rock weighs the same as it did before the last test).

You could also summarize results with a table - force required for cut #1, and then force required to cut every 25th cut (any interval could be used).
 
Allan Molstad: Since people have been calling for more quantitative results in my testing. I will do it the best way I know how. Something for everyone.

The Destruction test will be performed after the cutting test.



Broos: Thanks for the tips and suggestions. I will check the equipment the best I can to ensure repetitive results.
 
I believe Phil Wilson stops cutting if the slice takes more than 12 lbs of pressure.
 
db: I'll look in to this. I seen text reviews on cutting tests stating they use up to 60 pounds this seems ridicules to me. They never say how they determine the weight or show photos.

Thanks
 
Dog of War: Thanks for the link. I defiantly built some fun spud guns as a kid
I wasn't very popular with the neighbors with potatoes flying around all day long.
 
You're welcome, noss. I always try to cooperate with the guy with the bigger potato gun. ;)

FYI I've been getting set up to do some edge retention testing with sisal rope myself, so did a quick test of force needed ... with a good, sharp blade, 5 lbs. of downward force will cut very nicely with only a short draw/slice. With good steel there's no question in my mind, you'd cut a lot of rope before you got to where 10 lbs. was needed. Phil Wilson's stopping point of 20 lbs. IMO is going to be pretty darned dull.

If it were me, I'd try to really limit the amount of the edge being used. If you set your machine for only 1" of travel on the slice, it's obviously going to take a lot less time and work (and rope) than if you're using a 5" slice. About 20% as much, I'd reckon. :)
 
Dog of War: Good point, I can set the machine from 0 to 6" of travel for the slice. At the moment I have it set to 2" I think 20 lbs is a good cut off mark.
When it comes down to it, it's a lot of weight.

Thanks again for the link. Very helpful :thumbup: I look forward to reading the results of your test.
 
Hi Noss4,

The first machine we built (early 90's) used a foam insulation as the material to cut. We found that getting consistency in the cutting medium was challenging. This particular foam was more consistent than any other material we could find at the time.

When CATRA finished their edge tester (mid 90's) , theirs worked better than ours so we ended up buying a CATRA. The CATRA uses a specifically formulated paper made specifically for the CATRA. the ingredients are very preceise (14% quartz, etc.).

the computer gives us mm per cut as well as a graph of the cutting sequence.

Pressure is consistent, paper is consistent, we use a goniometer to maintain consistent edge angles, and we use consistent belts to sharpen. The CATRA is expensive, but it's the most reliable, repeatable edge tester we've been able to find. there are approx 22 machines worldwide.

Your machine is quite interesting. You are to be commended. :thumbup:

sal
 
Sal Glesser: Thanks Sal, I was wondering about a CATRA ? Thanks for the info on it. :thumbup:
 
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