True Grass Machete Pre- Order Closing 10/31

Hey guys,

A customer had one of these break. The customer indicated that it snapped during the first use while chopping. Thankfully he wasn't hurt.

The blade was send to Peter's HT to figure out what went wrong and after looking at all the factors there is no clear indication of what caused the failure. HT was on point, there were no cracks or bubbles in the steel. Brad found one very small inclusion in the steel but not something that should cause a break. At the end of the day, there is nothing we can point the finger to for causing the failure and based on all the info, I think I just have to chalk it up to a fluke. I've made hundreds of knives, most of them big hard use choppers and this was the first failure I've had. I want to do everything I can to make sure it never happens again but I'm scratching my head for what could be changed. As you guys know, I always use top end steels, only the best HT formulas, and test all of my designs extensively, which usually includes testing to failure.

Even when the best steel, best HT, and best production methods are used, it appears that things call still go wrong without a clear answer as to why.

Bottom line is 3V blades should never break during normal use. If you have a 3V TGM have been using it for the past few months without issue, then I wouldn't worry. However, please make sure you wear proper eye protection and gloves when you are using it and to that extent, any knife of mine. You should already be doing this anyway when swinging around a big ass sharpened piece of metal. ;)

Thanks and please let me know if you ever encounter a problem with your blade and remember YOUR BLADE IS WARRANTIED FOR LIFE. :thumbsup:
 
On a single instance like this, would be hard to point to any design, HT or steel flaws. Without knowing exactly what was being done at the time and the lack of other reports of the same....would certainly cause a person to think it was a fluke accident.

I certainly do appreciate your full disclosure and reassurance that you stand behind your work. One of the many reasons I come to you for the big blades.
 
Mink said:
On a single instance like this, would be hard to point to any design, HT or steel flaws. Without knowing exactly what was being done at the time and the lack of other reports of the same....would certainly cause a person to think it was a fluke accident.

I certainly do appreciate your full disclosure and reassurance that you stand behind your work. One of the many reasons I come to you for the big blades.
Click to expand...

I broke the blade and Hunter handled the situation very well. I was surprised that it happened. I was chopping up some greenish sassafras about 1-1.5 inches in diameter. I didn't hit a knot or any other hard inclusions. There was no damage to the edge after it broke. It was just really strange that it happened and wanted to make sure it wasn't a potential heat treat issue with the entire batch thankfully it wasn't.
 
Kyle,

Thanks for the additional info. I have used mine on green pine limbs with no issues so far. Hope that remains the case.

Kirk
 
for those of you who like blade carnage

27647332408_a72ebc8e83_b.jpg
 
That's an amazingly clean line/break. Is the blade/steel slab welding or something from the steel supplier? I can't say I've seen many blades break but I don't remember them being so straight in youtube destruction test videos where HT testing was going on.
 
Kyle,

Thanks for posting the info and the pic:thumbsup:

Bikerector,

A break like that is something I've never experienced and I've personally testing dozens of blades to destruction. Even when you put them in the vice and crank them until they snap you rarely get a straight line break like that.

I was very fortunate to have someone as experienced and knowledgable as Brad Stallsmith help me try to find answers. Brad tested the steel to make sure it was genuine 3V, tested the hardness and it was on point, and looked at it under the microscope and didn't see any clear problems. The grain looked very nice. On my end, there isn't alot of steel removed when grinding and the temps are always kept cool with quenching every pass or two-- not much room for a problem to arise. We weren't able to find any leads as to what happened.

As we all know, 3V is as tough as it gets and should be able to take extreme abuse, even in a thin blade, before snapping. On top of that 3V is made in America by a really sound and controlled production process. Brad was just as shocked as Kyle and I were.

I'm going to see if Brad will send me the blade back and I'm going to destruction test the remainder of the blade after I take the Bar exam.
 
I assume that is a (.085).
My Extra Thin has held up will slashing vines and grasses.
Great sharpening job on my .070 as well.
That break is freakishly clean and straight,wonder if resonance played a role in the break
since the blade is so long and thin??? Just a thought
 
On the plus side what remains looks like an excellent competition chopper. Thanks for reporting back on this, sounds like a freak occurrence. I've been using my .07" without problems. I might try whacking some hardwood just to see what happens.
 
Good point, was this the normal thickness TGM or the thinner variety?
 
Thanks for keeping us in the loop and glad you are doing what you can to make sense of it. I have only used my thin TGM as a heavy-duty weed whacker - overgrown old field stuff that chokes a weed whacker (thistle, stinging nettle, worm wood and tall grass (smooth brome)) and it eats through that stuff great. No woody stemmed stuff, though, and no hardwood for sure. I remember thinking that I was glad to have the full reach of the blade and the thinner stock makes it easier to swing for my tendinitis-prone elbows. So good review from me, so far. I do have some thicket stuff to remove, so we'll see how that goes.
 
I have never seen a break like that. Crazy. Thanks for being so open Hunter. I look forward to my next knife from you!

P.s. I do terrible things I shouldn't with your blades and they do great!
 
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