well i dont know what to think so ill tell the story and listen as you boys chime in....here we go.

i had recently got a used df,i had also got an rd-9.i had the day off and figured id catch a buzz and pit the two against each other.i also had a yh,chopweiler,dm,rd-7 and rd-4 to play with.any way...long story short,i was chopping and battoning and when i got home i noticed a small,yet noticeable ding in the df blade.

im not sure if you would call it a "ding" or "roll".i admit it is small and with my cheap camera and lack of skills i probably couldnt get a worthy pic up.

anyways....i was beating on it hard but it was only a 6in diameter log.it did have a not in it,but still,it is only wood.is this normal?

i dont want any refund or to send it in.its not like i can get a new one and it is a small ding,yet noticeable.what do you guys suggest to remedy the ding as far as sharpening it out?....and has anyone had similar experiences?

i am kind of bummed out after hearing about what a good chopper it is and having it ding my second time out on some wood.dont get me wrong,im not mad or complaining....just looking for advice from my fellow mutts,hounds and dogs

thanks

A ding or roll is ok, that is what it is supposed to do as opposed to chipping. I rolled or "dinged" my SHBM when in Kenya back in 2000 only because it sliced through the wood and caught a rock on the other side. It did what it was supposed to do and rolled. Cheaper or badly heat treated knives would have chipped. I used that SHBM for two months without sharpening it or fixing the ding. In fact it is still dinged as I have yet to sharpen it since 2000.

Don't let it bother you as the knife did what it was supposed to. I will let others here help you out with how to fix it.

Now I must say that I did chip my DF only because it was one of those that slipped though with a poor heat treat. It was nobody's fault, there will always be a bad apple in the bunch no matter who makes it or where it came from. All knife makers have a bad one now and again. Dan replaced it and the new one has been beaten badly and just laughs at me. I have yet to destroy it.

I am sure HD, Andy or someone else can give the advice when it comes to fixing it. Until then do not be bummed out... The knife did what it was supposed to do.

Did it look a bit like my Dogfather.

http://i227.photobucket.com/albums/dd99/darkjedi7777/HPIM0467.jpg

WTF did you do to your dogfather darkjedi!?
i don't think that would have happened if you choped rocks with it. you might have a defective one. imo, but i may be wrong.

but anyways, a small ding or roll is nothing to be concerned about, i doubt its a chip. if it is a ding or roll the guys here can tell you what to do. but don't worry, even if it was a chip, you can sharpen it out(or try) and it will work just fine i'm sure.

Northern,

I was about to chime in here and suggest that small dings and/or rolls are very normal with normal heavy duty use.... As long as not crazy rolling on light use. or significant chips. Even "Super" steel is still steel.

Jackhammer bits are tough steel to do the job, but they still get damaged and will get dinged, slightly deformed and need re-sharpened. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> .... * But, they rarely have significant failure or loose significant chips.

Also keep in mind that it is not uncommon for trees to have small rocks imbedded in them or nails. Small rocks can do more damage than most common nails.


Then I saw Darkjedi-Dog's pic... <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

Natural question: What the heck happened there?????

But, I am going to assume that damage is based on some VERY severe abuse.
Any knife and any steel can be beaten to damage. So, the fact that you post a picture of a damaged knife doesn't in itself bother me.

HOWEVER, in all Fairness, I think if you are going to post a picture of a Scrap Yard blade like that you should EXPLAIN the picture.

What did you do?
What happened?

You post it as if to suggest your Dogfather failed. I don't want to assume this without knowing what you did to it. I don't feel that it was fair to just toss that picture in without explanation.

.... However, I am concerned about that hollow spot in the middle of the blade. (????????) - looks like a bubble in the steel or something (?????????????) <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

Is that a chip or an air bubble?

Will your camera get a micro close-up of that spot?

..... and could you please explain what you did to your DF?

.

yeah it looke like the steel is like.... hollow in that spot or something.
it looks weird, even with huge chips taken out of the blade i dont think it should look like that.

.... Actually, I tend to believe rocks could easily do that type of damage to SR-77.

.......Better than what rocks could do to most types of steel that are more brittle and not as tough though!

Cinder blocks could over time do that type of damage and cinder blocks are often (can be) softer than many types of rocks.
It depends on the rocks and the composition of the cinder blocks as well.

There is a large range of hardness among different types of stones and rocks. And there are variables in cinder block composition as well.

There are specialty steels such as S7 that are designed and used to bust rocks, but that doesn't mean the steel won't or can't be damaged by doing their job. Especially when the edge is thinly shaped for knife use.

Diamonds are the hardest substance on this planet (that we know of).
Diamonds are commonly used embedded in blades to help cut stone, but even diamonds will fragment, chip, dull and wear out.

I don't think people should be surprisd to see a damaged Scrap Yard blade if the blade was subjected to extreme abuse.

These knives are often tested against tough materials to see how tough the blades are, but that doesn't mean that such tests are not "Abuse".

Chopping stone or rocks with a knife - even a Scrap Yard knife is still ABUSE!

SR-77 can probably handle hitting rocks or stone better than most knife steels in that it won't easily break or chip. But, that doesn't mean SR-77 in a knife form is intended to bust stone and rocks without any damage.

SR-77 is a type of steel that should not likely "break" (or break "much" ?) with such abuse, but for the thin edge to be damaged "SHOULD" be expected.

Actually, as far as edges go, SR-77 does NOT have the hardest edges. If it did, the edges would be more prone to chipping and fractures when hitting stone or similarly hard materials. The edges are actually softer to help prevent chipping and fractures. This in turn is going to allow the edges to roll and deform just a little easier. - which is better than chipping and breaking.

Damage can and will happen if beating on rocks, stone, cement and similar hard materials!

Damage can happen even from wood. However, the damage from (Clean) wood should be pretty minimal as the steel should be significantly harder than the wood. (For the record, Petrified wood is not wood!)

The "toughness" of a knife comes into play because of the torque generated upon the conact spot of a blade when striking a solid (not neccessarily hard) object.

A blade will snap at point of impact or it's weakest point because the torque or force the blade experiences when it comes to a hard and sudden impact. Consider how a stick breaks when you hit it against a tree. The weight of the stick forward of the impact point continues. The velocity at the tip combined with the weight of material forward of the impact point can equate to significant amounts of torque on the impact point.

SR-77 is MUCH more capable of resisting this type of damage from torque than most types of knife steel.
There are other types of steel that can easily handle this type of torque, but they are not as hard as SR-77 and won't hold a knife edge like SR-77. It is a balancing act of knife characteristics and properties that we have to deal with.

Edge holding vs. Toughness vs. ability to sharpen


In reference to knife steel vs. Rock, some understanding of Mohs Hardness scale might be helpful!!!

Hardness Mineral Absolute Hardness
1 - Talc - 1
2 - Gypsum - 2
3 - Calcite - 9
4 - Fluorite - 21
5 - Apatite - 48
6 - Orthoclase Feldspar - 72
7 - Quartz - 100
8 - Topaz - 200
9 - Corundum - 400 (Rubies and shaphire)
10 - Diamond - 1500


* Orthoclase Feldspar is a common mineral mixed with Quartz (and other elements) to create granite.
So, granite being one of the most common types of igneous rock, falls in around 6-8 on the Mohs' hardness scale depending on many factors.

** Quatz can actually reach 9 on the Mohs' scale.

But, granite, being one of the more common types of rocks is "harder" than most knife steels. Some rocks are harder. Some rocks are softer.



On the Mohs' Hardness scale:

pencil lead has a hardness of 1;
fingernail has hardness 2.5;
Gold, Silver & aluminum range from 2.5 to 3.0;
a copper penny is about 3.5;
a knife blade, 5.5 (depending on type of steel);
window glass, 5.5 to 6;
steel file, 6.5
Tungsten Carbide, between 8-9 (about 88 - 90 Rockwell Hardness!)



A common test in the world of geology is called the "scratch test". The test is commonly done in the field where lab and chemical type testing is not practical. The concept is that based on knowing certain common hardnesses of certain elements, the harder will scratch the softer elements. This test is done to "help" determine types of minerals in the field. It is not a perfect science as there are often many variables in geology.

It should be noted that (like knives) certain elements can actually have a range on the scale based on purity and formation.


It should also be understood that there is a difference between hardness and toughness! And that hardness and toughness aren't always hand in hand.

I am going to make up some "general" definitions here, but they seem about right:

I would loosely define "toughness" as the ability to resist breaking.
And "Hardness" as the ability to resist deformation.


*** I don't believe the definitions of toughness and hardness can really be made that simple. But, that is a start.



Nevertheless, hardness is going to be pretty directly related to scratching, denting and deformation of materials.

Diamonds will scratch and dent steel. Diamonds are often on the tip of Rockwell hardness testing tools - especially for tools intended to test harder types of steel such as knife steels.
Sometimes Metal balls are used in hardness testing equipment. I assume metal balls are cheaper, but I assume metal balls would only be used for for testing softer steels.
I doubt they can use a metal ball to test knife steel (????) - as I would think the hardess of the metal ball would be to similar in hardness to the knife steel. - Unless they use a Tungsten carbide ball or something (???)

I could mention a little about the Rockwell Hardness scale here as well.
First, the Rockwell hardness scale is generally focused on hardness of steel.
The Rockwell hardness test is basically a "Dent" test.

Dentabillity and malleability are going to have some similarities in knife steel. But, it isn't easy AT ALL to simplify the characteristics of knife steel. There are MANY factors and characteristics involved.

When comparing knife blades to each other, Rockwell hardness is going to be a better and more accurate measure of hardness than Mohs' hardness scale. .... is why the knife industry uses the Rockwell Hardness Scale. But, the Rockwell hardness scale is not generally used to classify hardness levels of rocks.

So, when comparing how a piece of steel will compare to rocks, the Mohs' scale is worth knowing about and knowing that knives hardened to about 56 - 60 on the Rockwell hardness scale fall at around 5.5 on the Mohs' hardness scale.

I don't honestly know what the Rockwell hardness is for SR-77. I assume it is around 57 or so (?????).
While there are harder steels, and the harder steels would be less prone to edge "deformation". Those harder steels are not going to be as tough as SR-77 and are going to be more prone to breaking and edge chipping.

Ideally, we could have knives with Super hard edges, that are super tough and reasonable to sharpen.

But, usually there are compromises. Usually, we have to trade one thing for another.

For SR-77, you get lots of toughness, but you do compromise some edge holding.
For S30V, you get good edge holding, but not quite as tough.

It is often good to know what the knife or tool is intended to do when considering the steel and heat-treatment used! <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

... And of course, with all of the different steel options and heat-treatments there is a LARGE range of variations of toughess, edge holding and ability to sharpen combination.

So far INFI is probably providing about the best "practical" combination for knife users (in the field) of toughness, edge holding and ability to sharpen. But, that is still debatable and it comes down to how you use and what you intend to use the knife for~!


*** There is also a Brinell and a Vickers hardness test...., but hopefully the above info helps explain why many types of ROCKS can and will deform and/or break many types of steel.


.

If that is a bubble in the edge, I would probably check into it and see about warranty based on a defective "bubble".

But, if that blade damage was caused by rocks, stone or similar abuse (as I assume it is), I would still describe the rest of the damage as abuse.

Where it not for the bubble and assuming I am correct about the rest of the damage, I don't personally feel the rest of the damage is a warranty issue.

From what I can tell, the knife was abused and yet did NOT break.

Edge damage from abuse (intentional or not) should be expected IMO.
This is still a knife and not intended for chopping rocks!
As I tried to show above, rocks can be and often are harder than knife steel.

Even though some types of steel can break or bust rocks, that doesn't mean the steel is harder than the rock. It means the steel is tough enough to be subjected to use against rock without breaking.
Again, keep in mind that jack hammer pits, picks and rock chisels are subject to tip deformation as well. They also require sharpening and similar maintenance. But, they also don't have as acute an angle as a knife edge!

These steels can be "deformed" against many types of rocks. - Especially when sharpened to an edge to be used as a knife!

Although, I suppose it could be debated and there could be a gray area as to how much deformation is exceptable vs. how much abuse. Or what is exceptable "damage". Very debatable! And probably hard to prove how much or how hard the knife was hacked against hard materials.

That is why I strongly feel there should be an explanation included with any pictures showing this type of edge damage.

In general, I think misunderstandings exist about what should be expected from many types of knife steel and pictures of damaged blades without explanations could cause unfair frenzies about the quality and abilities of ANY knife steel.



Anyone who takes any type of steel including some of the hardest steels we know of like Tungsten Carbide and whacks it hard enough and often enough against certain types of "hard" rock are going to see damage of some sort - Deformation, denting, rolling, chipping and/or breaking!

There is no steel made that can't be damaged to some degree with certain types of abuse.





In all fairness to Dan and Scrap Yard, we should expect to hear about what was done to the knife to cause the damage before making harsh judgements and we should understand that edge deformation can and will happen even to SR-77 with certain types of knife abuse.

If that DF was used "heavily" against rocks or similarly hard materials, then I "could" possibly argue that it looks pretty decent (not including what appears to be a bubble).

In the knife world, denting and rolling is generally better than chipping, breaking or fracturing.

.

I got a couple really small "dings" on my DF the first time I went out - probably little pebble or something on the log - anyways, I've used the crap out of it since then with not issues what so ever. I'm inclined to think its just a fluke - run a rod over it, strop it a little, and drive on!! Thats what I did - and I was pretty concerned as you must be as well.

A chip is a different story - but a little roll spot for a small pebble or rock on the log won't be a big deal.

Post pix if you can!

If you are going to use a hard use knife then you need to learn how to sharpen!

You cant avoid a nick forever on the edge, it is bound to happen. As long as there wasn't a big chunk of steel missing, then steel the edge lightly & sharpen it.

My personal stance on the little nicks is to not sharpen them right out. Why wear the blade back a mm or 2 every time? Over time as I sharpen them more they will disappear & they don't seem to compromise the chopping!