O1 utility knife

[Cliff Stamp]

This is a really nice utility kitchen knife, which is its actual design. Due to the fairly narrow blade it works well doing paring work, easily slices up roasts and can also work on vetagables by altering the normal grip. Though for the latter cutting a dropped blade profile is more efficient in the long run due to lower hand fatigue.

Of course being curious about the ability of the steel and especially the durability and scope of work of the blade which such an extreme profile I used it for a lot more work including pushing it to the point where the edge finally cracked trying to rock through the bottom of a 2L coke bottle.

There were two main edge retention trials, one on cardboard vs a S30V Sebenza which was a total blowout even with really heavy bevels to compensate for the lack of strength of the stainless steel. Then another much more demanding one cutting used carpet.

It was raining off and on during the carpet cutting, and it was also below zero at times so some of the runs on the carpet were cutting it frozen which curiously enough makes it easier to cut. Not only was the carpet used it was actually outside on the ground for four months.

It was interesting to compare this to the small paring knife which has a similar grind. For a lot of cutting the extra length of the O1 blade comes in handy, cutting weeds outside for example and in a lot of work in the kitchen. However the shorter blade on the paring knife is nicer when carving and for a lot of utility work such as cutting cardboard.

Ref :

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

I have more work with this one planned, including some coarse edge retention work as well as comparing it to a M2 blade at 65 HRC.

-Cliff

 

[sodak]

Thanks for the review Cliff. Very informative! Hmm... I've got an O1 knife on order, I might have to be specific as to the Rc hardness after reading this. Did you have the Sebenza rehardened, or is it stock? I have a couple of small S30V folders that I'm going to send off for "improved" heat treating.....

 

[db]

Very interesting on the plastic 2L bottle bottom. For those that haven’t tried it it can be difficult to do. I’m no longer sure what cutting through the bottom middle of the bottle really can show. I did it with a knife I reprofiled to see if I ground it too thin. It went through the middle of 2 different bottles with no damage at all so I thought it was good. However, the next day I cut 2 of those plastic packing strips around the outside of a box and the edge was fried. Rolled bad with some chip/tears. So how hard the plastic bottle trick is for a knife’s edge makes me wonder.

 

[Cliff Stamp]

I've got an O1 knife on order, I might have to be specific as to the Rc hardness after reading this.

How it is hardened is quite critical, some of the properties have very narrow maximum peaks, only 1-2 hrc can cut them in half. The review contains the specific method needed to hit the torsional toughness peak which also gives a very high strength.

Did you have the Sebenza rehardened ...

Not yet.

I did it with a knife I reprofiled to see if I ground it too thin. It went through the middle of 2 different bottles with no damage at all so I thought it was good. However, the next day I cut 2 of those plastic packing strips around the outside of a box and the edge was fried. Rolled bad with some chip/tears. So how hard the plastic bottle trick is for a knife’s edge makes me wonder.

Plastic is quite soft, it can't directly roll the edge, the issue with the bottom of a coke bottle is that it takes a decent amount of force to push the knife through around 50 lbs and so if there is any side loading it can induce a fairly decent stress on the edge.

Steve Harvey was the first person I saw talk about this in regards for durability after noticing that it damaged the edge on a Talonite blade. I have since done it with the same O1 blade with a more controlled cut but it took a lot of care, the main issue then is the stability of the cut.

-Cliff

 

[db]

Yep I remember it took a piece out of Walt's Talonite blade that is when I started useing it to see if a blade I reprofiled was too thin. Maybe I should look for a roll of that plastic packing strip stuff to use instead. Wish I'd of held on to that stuff.

 

[Cliff Stamp]

I updated the carpet cutting table, adding the results of a few blades which correlate well to work done previously comparing S30V and D2. I also plan to add blades in VG-10, the Byrd steel and hopefully M2 if I don't run out of carpet.

-Cliff