6061 T6 aluminum durability?

Heartland_edc

Heartland_edc

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May 4, 2015
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I have an auto on the way that has handles made from 6061 T6. Ive owned many like this before, but never really put them to the test. 2 questions:

1. Exactly how durable is this grade of aluminum vs 6al4v titanium when used "hard"? And im talking used, not abused. Say I drop it every now and then or bare down on it while cutting wood or some other material that creates resistance. Does it warp/bend/ding/rust easily vs titanium?

2. Why is almost every single automatic knife on the market made out of either 6061 T6 or steel? Why no titanium? Is there some advantage to it other than cost of manufacturing? Obviously it's lightweight, but so is titanium.

I would very much like to hear what everyone thinks.
 
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Part of the "durability" is the anodization. Mil-spec, hard anodized, HA level 3, HAIII, etc (all the same thing) will give much better cosmetic durability than lesser anodization. "Scratches" on HAIII are usually actually not a scratch in the aluminum/anodization itself, but rather material deposited in it. IE, a coin or key rubs against the knife, it's the coin or key that gets damaged against the anodization (think of it like chalk on a board).

That said, aluminum is soft, so deeper gouges or dings from harder impacts will damage the anodization and/or deform the aluminum underneath. However, it's extremely unlikely you'd be able to damage the knife's handles enough to affect the function of the knife. Most (if not all) moving parts and surfaces that contact each other will be made with steel (IE: the plunge lock, stop pin, and blade on a push button auto). You'd have to do something deliberately destructive to ruin the knife.

Aluminum is far easier and cheaper to produce and machine compared to steel or titanium. In plunge locks and OTFs, the mechanisms don't require long-term wear resistance or toughness (like a liner/frame lock does), so aluminum works just fine. Keeps costs down, and is a lot lighter than steel and even titanium. When you see steel or titanium, it's usually in a very high-end knife, or a custom version of a regular model (think Microtech or Protech) that costs far more than the basic one.
 
Glad to help. What knife did you get BTW?
 
Check it out. Here is aluminum bodied Extrema Ratio RAO2 vs Cold Steel triad.
EX130RAOna.jpg


Here is an interesting video. Skip to 13:40 to see what happens to the aluminum handle. Still the RAO was holding a TON of weight before it broke, so aluminum did ok.


 
Heartland_edc said:
Protech Rockeye auto.
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Sweet. The handles (and blade) are DLC (diamond like coating) coated, which is pretty tough stuff. I'm not sure how it compares to HAIII anodizing, but if they used it on that kind of knife, it must hold up pretty well. Enjoy your new tool/toy.
 
BTW, going back to your original post, the steel handled version of the Rockeye is more than twice the weight and more than twice the price. 9.5oz is one heavy brick in your pocket.
 
Ya I noticed that. I'm not usually the type of person who is bothered by a heavier than normal edc, but I'm also not the type of person who enjoys having their pants drop in public...
 
In the usage case you describe there is no disadvantage at all to aluminum for the frame. You will not see flex, warping, etc.

Aluminum won't rust, it does oxidize on the surface but not like steel does - it's more of a hard surface layer that prevents oxidization going deeper. You can get galvanic corrosion though but that is extremely unlikely to be an issue under any normal situation, IOW don't leave it in a bucket of salt water ;)
 
palonej said:
This TR3, I have 3 of them, is my most carried and used. The aluminum feels great in hand and holds up nicely. PT is a great company that makes some bad ass knives!
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Awesome to hear! I'm really excited. It is in fact my first Pro Tech. Not sure why I waited so long to pull the trigger on one, but everyone sure seems to like them!
 
It is fantastically durable and strong. I have worked with high end HEAVILY USED sporting equipment made out of this stuff . . . think 250 LB dudes going all out and jumping off stuff on a 20 LB bicycle for years nearly every decent weather day of the week . . . no prob.

I very rarely see a crack and it is almost always due to welds that are too thick CAUSING a stress riser. It breaks right along the edge of the weld. If the weld is right ( thinner ) every thing flexes as a single unit and it just goes for years and years.

Seven thousand series on the other hand I have seen tons of failures. In fact if I see a very serious cyclist buy a seven thousand series bike (which are usually lower price to start with ) I just start counting the months until it comes in with a broken frame. Like clock work; it's crap for that application.

That's thirty years of experience talking.

And finally they make air planes out of 6061. Sure it has a limited life but the planes are flying night and day almost continuously right ?

It's good !!!! Don't worry. Use it. One example is it is used for frame liners in a fantastically good knife, the Cold Steel Voyager.

Bottom knife in this photo and it can hang with the other two for sure. Great knife. Light and strong.IMG_4339.jpg
 
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I'm surprised to see aluminum used as a liner, I would have thought at those thicknesses it would not have the strength required.

Btw, used to be a mechanic/sales/parts guy myself. Not a huge fan of aluminum tbh, unless it's FS, I prefer Ti or even steel. I've seen all materials fail though, either next to the weld like you are talking about or sheared near the rear dropout. Carbon just ends in a pile :D
 
Icehawk said:
I'm surprised to see aluminum used as a liner, I would have thought at those thicknesses it would not have the strength required.

Btw, used to be a mechanic/sales/parts guy myself. Not a huge fan of aluminum tbh, unless it's FS, I prefer Ti or even steel. I've seen all materials fail though, either next to the weld like you are talking about or sheared near the rear dropout. Carbon just ends in a pile :D
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I agree. I've never owned an alu frame; kinda fat and ugly. They make great "thowaway race bikes" though especially Cannondale. I'm a steel frame man my self; old school Columbus SL. (but I'm built like a climber (small and light for you muggles). I have NEVER seen a Ti frame break. Nice tiny thin welds.

I hate carbon period . . . don't get me started.
 
As far as strength of thin heat treated alu.
Try something : go find a trashed XTR derailleur cage. Put it in a vise and first just try to bend it into a different shape. Stuff is like spring steel. Then bend it until you break it off.

You will have a new respect for alu that is heat treated well . . . AND for XTR components in general ! ! !.
 
Wowbagger said:
I have NEVER seen a Ti frame break. Nice tiny thin welds.
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OK one more. One of my customers literally over seven feet tall; I'm thinking 280 LB lean . . . right . . . probably a billionaire . . . a big man in many ways. He has to ride custom frames; only thing big enough. His wife bought him a custom Zinn full suspension a few years ago in alu. Literally the bike is over $10,000.

What does he ride ? What did he bring in and have me go through and replace most of the turning parts on because he wore them until they were falling off the bike ?
His old Titanium Black Sheep hard tail. He has had it for ten years plus that I know about.
No cracks.
Dude needs a motorcycle grade drive train though. He was pleading with me to find such a thing to put on his bike so it would hold up.
 
Own several Protechs. That aluminum is tough stuff in fact, I prefer it.
 
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