1095 blade damaged chopping wood(is this normal)

B

Ben E. Hana

Joined
Nov 22, 2000
Messages
53
there is a thread going on in the general forum about warranty.Cliff stamp damaged a Livesay RCM limbing out a juniper.The damage as reported extends 1cm into the blade.Newt tested the damaged blade and found RC within spec.Another guy said his RTAK(1095) was also damaged chopping wood (aspen I believe) but that for him he expected that because the steel was 1095.
Is this normal for properly hardened steel(1095) to distort while chopping wood?I'll leave it to the experts here to comment as I feel makers are the ones to go to for answers to these type of questions..
thanks guys
troy
 
I would question the hardness of the edge area. It is difficult to rockwell test the tapered edge with the rockwell tester. The flat area may be correct but it sounds like its soft at the edge.Did it chip or dent? Is it a custom or factory knife? Bruce
 
Dave Ellis, ABS, M.S. here- My personal opinion is that 1095 is a bit hard for a chopping knife I generally use 1060 or 5160 for larger Bowies and 1094 for samller hunters, sportsmans and some fighters. Hope this helps.
Dave
http://www.exquisiteknives.com

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This afternoon I took the RCM out for an extended period of hardwood chopping. I took the Battle Mistress along and alternated between the two blades every 100 chops. After 500 chops the RCM had rippled along the edge. The edge had bent about 1 mm or so to the side with the dent extending about 3.5 cm. This deformation ran about a cm deep into the blade.
Heres the original report

thanks for the replies so far.
 
My opinion..........It is a combination of factors that lead to the damages.
The hardness level, combined with the blades geometry were not correctly matched for the task of chopping. Judging from the description of the damage, I would bet the blade is flat ground. If indeed it is flat ground..........had the same blade been ground to a fine convex, there would likely have been no damage. This is a prime example for explaining what I call the "Overall Package" in a knife. All aspects from steel type, to hardness level, to grinds and finishes must be taken into consideration as to how the combination of those given areas will effect the end product, and the tasks it is asked to do. Having tested a great many blades, it has become very obvious to me that even slight combination changes of steel, harndness, grind, etc. Can, and often do have dramatic effects on the durability, or lack thereof in a given design.


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Ed Caffrey "The Montana Bladesmith"
ABS Mastersmith
www.caffreyknives.com
 
Ed and Dave are VERRRRRY Wise! I am listening with both ears! The overall package concept is interesting Ed, definitely something to keep in mind with every knife purchase (and every time I make a knife!) I wonder whether the RCM was even designed for chopping junipers all day. It is a machete designed to be a mercedes among $10 machetes. How would it do against an Ontario machede which was used to chop Juniper 500 times I wonder.

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"Come What May..."
 
Crayola ,An ontario machete was used by the same tester on the same wood in the same way and showed no damage.
troy
 
Thanks Ben. I read the post a week ago about the RCM and I thought an Ontario was mentioned but I was pretty sure it wasn't tested in the same manner.

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"Come What May..."
 
The review, which includes references to all discussions about the blade I had with Newt and describes the damage in detail as well as his conclusion :

http://www.physics.mun.ca/~sstamp/knives/RCM.html

The Ontario machetes used in the same manner, also 1095, took more damage. They suffered very large chips :

http://www.physics.mun.ca/~sstamp/knives/machete_ontario.html

The Tramontina suffered no damage except a slight bend in the blade (from different work, chopping into a decent sized tree) :

http://www.physics.mun.ca/~sstamp/knives/tramontina_machete.html

The reason the Tramontina was as durable is because it was not nearly seeing the same level of stress. The Ontarios are 50% heavier which greatly increases the amount of impact energy in and of itself, but due to the extra mass I could swing with them driving from the shoulder, with the Tramontina due to its light mass this was not productive as it would reach max speed from just an elbow drive. I would estimate the Ontarios (and the RCM) were taking at least 400%+ more energitic impacts.

In regards to the convex grind, yes this is the same conclusion that I came to shortly after. I am thinking of getting a couple of blades made about 10-14" in length with convex grinds, no secondary bevel if it has the necessary level of durability. I would like 3/16" stock if possible, steel suggestions welcome, I am thinking of 3V out of curiosity but something like L6 and S7 are interesting as well.

-Cliff
 
<font face="Verdana, Arial" size="2">Originally posted by Cliff Stamp:
I am thinking of getting a couple of blades made about 10-14" in length with convex grinds, no secondary bevel if it has the necessary level of durability</font>
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Cliff -- How would the profile differ from the Hossom 3V machete I described recently? Flat grind transitioning to the convex edge, rather than the full blade thickness at top of the convex edge? Do you have an idea of what the flat grind profile angle would be? I think you're on the right track, though the blade thickness @ 3/16" sounds like overkill to me.

--Will
 
Will :

<font face="Verdana, Arial" size="2">Flat grind transitioning to the convex edge, rather than the full blade thickness at top of the convex edge?</font>
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Primary convex grinds if possible, flat if not.

<font face="Verdana, Arial" size="2">Do you have an idea of what the flat grind profile angle would be?</font>
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Right now I am thinking of a 2" wide blade if possible, but at least 1.5". With 3/16" stock a 2" wide blade would be about 3 degrees, 1.5" about 4. I would go with the wider blade to get the extra mass and more acute profile *if* the steel could handle it. As you gain in mass and make the edge more acute at the same time, this obviously will quickly lead to a point at which the edge becomes more fragile. Convex grinds will of course alter the edge angles depending on the degree of curvature.


<font face="Verdana, Arial" size="2">the blade thickness @ 3/16" sounds like overkill</font>
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Note that a full flat grind on 3/16" stock leaves much of the blade thinner than 1/8", the average thickness is lower as is the mass (25%). The cutting ability will be greater for low penetration work, and I would estimate that you would need near full width penetration before the 1/8" caught up, as which point unless the wood was splitting easily or the vegetation is dead soft, binding will be extreme on the flats of the 1/8" blade.

-Cliff

[This message has been edited by Cliff Stamp (edited 12-22-2000).]
 
I always thought machettes were for chopping brush and undergrowth , not trees. If you want to chop on trees I would think a small hatchet or ax would be more useful and they have a convex grind.

Arthur D. Washburn
ADW Custom Knives
 
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