Testing blade performance

Rick Baum

Rick Baum

Joined
Mar 14, 2000
Messages
509
I'm curious, when I read that people like Ed Fowler has achieved 1,000 cuts on hemp rope and flexed a blade 180 degrees 11 times...

A. What diameter/brand of hemp rope is being used? Do we as a knife brotherhood have an established standard so that my tests are in some way comparable to Ed's or Dahqotah's or Bill Burke's or whoever's.

B. I assume that by a 180 degree flex, that means once the blade has been flexed 90 degrees in one direction, the first 180 degree flex occures when flexed back the other direction 90 degrees past the original vertical position. What occured after the 11th flex? Did the blade finally snap, did it get the first crack in the edge?

I think that we need to form a standardized "perfomance knife bandwagon" for us to jump on. Otherwise were all trying to hit a moving target, so to speak.

Thoughts?

Rick
 
Not shure it's posible to get a standard testing like this. The ABS has the rope cut/2x4 chop/90deg. bend test, and it's a good measure of performance, but even that's subjective.

But rope varies from batch to batch, and even in the same batch you can get harder/coarser strands and softer easier to cut strands in the same lay.

The best I have been able to come up with is a profesionly heat treated ATS-34 test blade to use to check the rope with first to make sure there are no surprises with the rope befor testing a new blade. Heat, humidity, the rope itself, methode of sharpening, edge geomitry, how tired you are, handle configuration, methoud of cutting, what your cutting the rope on and more can efect what someone on the other side of the US is doing to what your doing.

I feel the only way to see how one of your blades compares to someone elsess is to test them side by side at the same time useing the same testing medium, eleminating as many variable as posible.

So far I've only been able to compare my blades to factory.

Maybe Ed can give us a few more ideas.:confused:
 
Will52100, It sure would be nice if we could come up with something... Otherwise, there are going to be people out there that will unravel a piece of hemp rope and start slicing a piece of 1/16th inch rope and claim to have a perfomance knife when they can get 300 or 400 cuts. I totally see your point (thought of it myself as I was starting this thread), it would just be nice if we could all get close with our testing mediums. I don't know about everyone else out there, but I'm about an 8 hour drive from the closest person that is genuinely concerned with perfomance, and I don't imagine he has a lot of time for side by side comparisons. I'm not trying to come up with something hard and fast, just something to let me know I'm approching a given level of performance.

Ed, What diameter of hemp rope do you use for testing? Did your blade completely break after the 11th 180 degree flex?

Rick
 
Rick: Next spring I plan on expanding my shop, acutally building a new one. I plan on hosting some seminars on the development of high performance blades. Standardized testing methods would follow. As you mentioned there are many variables, they can all be defined. I hope one day to see a society devoted to the high performace blade, with standards for any blade.

The standards would not limit the knife, merely a statement of function. ie. this blade will do x cuts on x rope. the blade will withstand x foot pounds of torque. The blade will made x 180 degree flexes. Something like that.

Should a high performance blade be designed for cut and not flex, it would qualify as a great cutter with no toughness. Just something that would allow method for a truth in advertising statement. Make what you want to make, but tell them what they are buying.

These are just my ideas at this time, the final form would grow with member participation. No smoke and mirrrors, just simple real wrold knife stuff.

Rick, if you got that barrel of Texaco Type A, this would be a place to sell it.
 
Rick,

I live in Salmon Idaho and it takes me only about six and a half hours to get to Salt lake. My shop is open any time and I always have time for testing. Just don't complain about the mess in or out side of the shop.:D For our comparison testing ed and I use one lay out of a piece of 1 1/8 hemp rope. We have a standard test blade that is used to test each batch new batch of rope so that we have a standard to go by.

In reference to the post on quenching oil. I had a local vender get some chevron quenching oil for me and guess where he got it yep from a chevron bulk plant in Salt Lake City. The five gallon can only cost thirty five bucks including shipping. I will check and see if I can get the name of the place for you. I do find it interesting that this guy had me a five gallon bucket in less than a week and the guy at the local chevron bulk plant said that he couldn't get it any longer. any way good luck and if you would like to visit just give me a call and head north.
 
It was like the blade we wrote up for the Blade Article, still could be straightened and used again as a knife. The question comes up as how far is good enough? Bill and I decided to quit flexing the blade that was in the article simply because it is hard to kill a champion. She had done enough. I bleieve that anything is possible in knife performace, the question is can anyone afford to own one? I made a Bowie blade, the one in my Ad. currently in Blade. She had over 7 complete normalizing heats during forging. The grain, temper lines and geometry all came together. I sold the knife to a man who had ordered it years previous. I sold it to him with a blend between what they were worth when he ordered and what I had in her. He was thrilled and so was I, the knife would not have been made without his order. A companion blade that received the same treatment was virtually indestructable and cut like a dream. I did not test that knife to total destruction.
 
That is what kills me about destructive testing, I just HATE to destroy a knife. I have done it a few times, especially after reading your book Ed(which is a really good book by the way), but it just kills me to break something that I put a lot of work into. My knives did ok on the testing (3 90 degree flexes before the edge cracked) but nothing like the performance that you are getting. Of course, up until now I have only quenched and tempered once per knife. And I was using 1095. But you get what I mean. I can barely afford good steel so each peice is pretty precious to me, and even though I only do this for fun and give almost all my knives away to friends and neighbors, I've already got a damn waiting list, so I can either give the knife to someone who really wants it or I can break it. Usually I go on ahead and give it to someone after I check to make sure it will hold a good edge. I know, shame on me for not fully testing, but like I said it just KILLS me to break a knife.

Chuck
 
Chuck: I well know the feeling, we get so involved with a blade that they become friends. I was at first obcessed with testing, did not finish a blade for over a year. I had a lot of questions that needed answers. When we destroy a blade in testing, it is an investment in all future blades. It is an investment in our future as well as security for our clients.
 
Yeah Ed, I know it is a good investment of time and materials that will pay big dividends in the long run, but when I'm standing there torqueing that blade it still kills me:)

Chuck
 
Chuck: There is another way to test blades with out destroying them. It is known as the tell tale etch. This year I had two blades that looked and cut very well. All was right, but when I etched them, faults became obvious. When we etch blades and understand what the etch reveals, we have an open book to read. I strongly suggest that anyone who is interested in high preformance blades etch all the blades you make. If you like a mirror or hand rubbed finish you can do that after the etch. The etched blade has no secrets from the maker or the client. And--you have the opportunity for learning you would have missed without the etch.
 
What a great thread this has turned into. Thank you all for your posts and the knowledge that I gain from each of you. I think I can relate to the "hate to destroy a knife" syndrome. Heck, I hate to see a knife leave my home after I've put 25-50 hours into one. They become a piece of me, and usually I become a piece of them. Literal blood, sweat and tears.

Bill, Thank you so much for you gracious invitation. As soon as I get a handle on this forging sport, I will definitely take you up on your offer. Right now I'm taking whatever steel I can find and practicing forging it to shape. I'll get into the heat treating once I get a handle on the proper shaping and working heats. I'm still trying to figure out if I have my forge tuned properly.:confused:

Ed, Does your new book cover the etch secrets that you mentioned in your last post. Do you have any update on the delivery date of the book. I'm looking very forward to reading/studying it.

At this point I'm excited about destroying a few knives but that is still a ways off.

Rick
 
Rick; The secrets of the etch run the gammit from simple to complex. At first you will notice only the temper line, then as your knowledge grows you will find there is a whole lot more to it. Your knowledge grows right along with your development of the steel you choose to use.

I am planning on writing another book, specifically concerning the forging and testing of knives. Some technical stuff, but simplified to the point that any man who chooses to forge blades will be able to understand completely. The knife is a tool that is subject to very simple testing of function. That is all that matters, and this is the art part. The science can loose a lot of folks, the tendeancy is to put too much emphasis on the technical that many times tells you that you can't do what you want to do. The art accomplishes the development, then let the scientist explain what happened.
 
Rick, you are right, this has become a great thread. I know what you mean about blood, sweat, and tears, I don't think I've made a knife yet that didn't cut the mess outa me at some point during its construction. All my knives are blood tested before they leave the shop:rolleyes:

Ed, you let us glimpse your wisdom yet again. I had tried doing the etch a few times and had gotten strange results that didn't make sense to me(lots of muddy looking swirls, whole blade turning black, things like that). So I just figured I wasn't good at etching yet, and from then on I just didn't do it figuring I needed some instruction in the etching process. I didn't want to use my etching solution on something if I didn't think it was giving me a true result.

The best etch lines I got were at the beginning when I was not heating the entire blade, just a half inch or so along the edge with one of those little hobby cutting torches. Those knives flexed real well but didn't hold a very good edge. I thought I was losing too much heat from the time I moved from the torch to the quench tray so I started using faster quench oils. The bacon grease and tranny fluid made the edges on those knives hard as rock, but I was still losing to much heat cause the backs were too soft if you bent them they bent and stayed that way.

When I got my propane forge I started heating the blades all the way through and edge quenching them still in a fast quench(I didn't think to change quench oil when I changed my method of heating. I think I was also heating the blades a little too much cause I got a couple of blades that snapped when I flexed them, I think due to grain growth from overheating past critical. I started watching my temps very carefully, and started getting blades that held a good edge and would flex well(3 90 degree bends before edge cracked) but that is when I started getting those wierd etch results. And basically quit etching blades. Since I started forging I have noticed a marked improvement in edge holding, but have not tested any blades past a 30 degree flex that I do to all my blades just to make sure they won't snap. I guess I figured that if I was getting a good level of performance but a wierd etch then there must be something wrong with the etch, not the blade. Since your reply I have started re-thinking that descision. Sorry to ramble on here but this stuff has all been bugging me and I figured since the subject came up I would let it all hang out.

Do you really have another book coming out? That is cool!

This is a great thread!

Chuck
 
Rick,

As I have been where you are, You will soon be where I am.

I can still remember what it is like to attack something that I know nothing about. If you truley want to make High Performance Knives then you should be working with a known steel. My suggestion is to round up all the load shafts that you can find and work them down into knives. A load shaft is a part out of a John Deere Tractor and are sometimes refered to as rock shafts. If I remember that part of the country correctly by heading south towards Parowaun (sp) you should run into a John Deere dealership quite frequently. Just go in and talk to the shop foreman. Ask if you can trade a box of dough nuts/ halfrack of bud or a knife for any used load shafts as might be laying around. You should be able to make it back home with enough of them to keep you busy for a while. The great thindg is that said shafts are made of 5160 spring steel and can be made into a very respectful knife. Also you can usually get them for cheap! this id a very forgiving steel and tolerates mistakes very well so you can heat treat them yourself and learn that art while you are learning to forge.

What Kind of forge are you using? Is it the standard Dragons breath forge? Do you run it with some flame coming out of the door? When mine is tuned properly I can leave a piece of steel in it and get it hot enough to melt without seeing any scale form until I take it out of forge.

My invitation is open and I will be happy to show you what little bit I know about forging also.

Bill
 
I strongly urge you to take Bill up on his generous offer. He is being modest about his ability, he is a first rate bladesmith! Working with a knowledgeable teacher can cut years off of your learning curve. If you are serious about knives, you cannot afford to pass up this sort of opportunity. Bill knows what I'm talking about because he had the opportunity to work with Ed (and don't forget all the hours and $$ Bill spent traveling back and forth to take advantage of this opportunity). I also was fortunate to work in the shop of JD Smith for a few years, and I still work with him 2-3 time a week. So I also know this sort of experience is invaluable.

Good luck,

John
 
John, Thanks for the advice. As soon as I get a little free time I will see if Bill and I can get together.

Bill, What in the heck were you doning in Parowan Utah? Must have been something pretty interesting, that was about a 10 hour drive for you. Probably a family reuniion, we probably hold the worlds record in this state and not by a per-capita standard either:D . I just called the local John Deere dealership. They have 2 load shafts for me that I'm picking up on my lunch break. I hope it forges easier than O-1. I was playing around with some 5/16" PG stock that was laying around. Sure didn't hold heat for very long! It seems like I would get it heated up and get about 10 hits on it then most of the color was gone. One thing that I have learned... Decide what your next hammer blows are going to before you heat the steel.

I almost forgot to mention.. Not sure what a dragons breath forge is, but mine is a piece of 6" pipe lined with insulation and some satainite or something like it. In my darkened shop I have a blue flame swirling out of both ends of the forge about 3 inches or so. It heats a piece of 5/16" X 1 1/4" O-1 to a nice orange glow in a minute or two. The way I have been running it, I don't get much scale at all when I bang on it. Does that sound right?

Just picked up the two load shafts... So do I need to anneal these before forging? I would guess that it would be a good thing to do.

Rick
 
Rick: Don't worry about annealing, just heat it up, weld it on a stick and go to work. The more normalizing heats you give it, while owrking it down, the better it gets. You will find it is the highest specked 516-0 around, Jong Deere is real serious when the purchase it for their load control shafts. I plan on working some again in the near future, applying all I learned with the 52100 steel and see how far it will go.
You wil find Bill is a good hand with steel. Maybe one day we will all be able to get together.
Good Luck.
 
Chuck; The etch will turn blackest where the hard part is. You get to read it when you put the blade on a loose musilin buff with something like Brownells 55 grey, then the grain will show. It is something you need to do a lot to get to know what it tells you. When you get little grain swirls,ask why they are there. Sometimes they are residual artifacts of the origonal forging operation before you started working on the steel. That is why I am so pleased with the steel we are getting from Rex Walter, it is very consistent.
If you cag get ahold of some of the John Deere Load control shafts you will find a new world opening up. They are very conisistent. If I haven't answered your questin ask again and I will try again.
 
Thanks for the encouragement Ed! I can't wait to make a knife out of it! I let the world know how it went. I don't own any cats though, so I don't think I'll have anything humorous to tell.. I'll leave that to Da qo 'tah.

Rick
 
Thanks for the reply Ed,

I will try to get ahold of some of them load control shafts to try out. I also have several small but thick leaf springs that say ford on the side of them, is that good 5160?

I can see right now that I need to go back to a baseline standard and start writing everything down and testing for results. In the near future I hope to get a mess of 1095 and do some testing on it. If I manage to get clear results I will post the end results for everyone here to benefit by.

This forum is the deal! Can't believe I'm getting advice from Ed Fowler on bladesmithing. Yours and Wayne Goddards books are what got me started making knives. Thanks!

Chuck
 
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