The "Ask Nathan a Question" Thread

Serious question, Nathan, will you give the AEBL with your heat treat protocol a name (like Delta for your secret-sauce 3V)?

Now the silly stuff,
If yes, can we help name it? Like stABEL. How about these...

Mothan ABEL (pronounced "MO than")
Mo Fracky ABEL
ABELNator

We need a name that steel contest. C'mon, man.

Fluffed ABEL?
 
TRfromMT said:
Serious question, Nathan, will you give the AEBL with your heat treat protocol a name (like Delta for your secret-sauce 3V)?
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3V was a steel with marvelous potential that was being heat treated with a process optimized for tool and die, which has thick sections, risk of cracking and distortion, and the application calls for minimal dimensional changes. My knives are measurably longer after heat treat due to expansion from martensite, which would be a problem in tool & die. These things lead to a slow quench, intentional stabilized retained austenite and utilizing the secondary hardening hump for the T&D application it was designed for. This gives good performance in a stamping tool but a chippy mushy edge when used in a knife due to softer carbon lean martensite and areas of RA that behave like the perforations in a sheet of postage stamps. So you end up with a steel that will tolerate rough use except the edge would go dull from poor edge stability. 10-15 years ago I was among a few makers buking the trend and utilizing heat treats that differed greatly from the data sheets. I used to get called out for blasphemy. I started with D2 but gravitated to 3V due to a better balance of properties.

3V is a complex steel with complex interactions. For example, an attempt to use a low temp tweak without addressing the RA through quench rate and quench depth could easily lead to worse results. The condition of the steel going into HT is an important variable. There are a couple aspects of the Delta protocol that are not intuitively obvious and work for 3V but not D2. I tweaked 3V over the course of several years before finally going through the laborious process of identifying and evaluating the effect of minor changes to a bunch of interconnected variables. I started having the steel made specifically for me buying entire "melts" and owning the entire heat lot. At this point I felt comfortable saying that my 3V with my HT is demonstrably different (and better) than the industry standard. They're really not the same thing. It is changed (Delta). So I added the Delta prefix to differentiate it from my earlier work and from other people's 3V. This was important because a lot of people had preconceived notions about the alloy and its ability to shrug off damage from rough use. I didn't want my work pre-judged from people's experience with the alloy from other makers. This is why it was named.

AEBL is a relatively simple steel. I'm not doing anything revolutionary with it. Doing a competent job on AEBL isn't rocket science. There is some low hanging fruit and I've picked it. That doesn't warrant a special name.
 
Nathan the Machinist said:
...That doesn't warrant a special name.
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All kidding aside, as a geeky engineer I really appreciate the complete explanation.
 
tinfoil hat timmy said:
images

The thing that this is escapes me. Lil help?
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Vanth Dreadstar, by Jim Starlin. Originally published in early ‘80’s.
I read these when they first came out.
Starlin also created characters of Gomora & Thanos.

Thought I was really cool for seeing Episode 4 on day 2 of opening weekend until my friend, Rusty, shot down my bragging with the blasé comment that he’d waited in line and seen it opening day.
 
I’m sure this has been asked and answered in this thread but how do you sharpen your knives? What do you use and what grit do you take them to?
 
Nathan the Machinist said:
1. If it were just me maintaining them I'd use my oil stones. I learned how to free-hand it and have no need or desire for a system for my own personal use.

2. Doing it in production and needing QA and repeatability it's done under flood coolant with a ceramic belt utilizing a parallelogram to control the angle, deburred on an Arkansas stone and stropped with a concoction of chromium oxide and diamond dust that I make.

3. The Behemoth is a fantastic knife, it might be my favorite. The Behemother is a variation that is a little bigger and utilizes the primary grind geometry we developed over time for the comp choppers and is one of the most effective choppers you'll ever use. Trekking in the forest, I'd grab an MC. It's light, well balanced and versatile. I can 5 hit a 2X4 with the BC, but I don't need that on a hike.
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Missed this a while back but I can support this statement as I very often "trek" in the forest (read: I work in the bush and carry this everyday). Also as far as sharpening....nothing more than a diamond/ceramic dual sided stone and a leather strop and has never been an issue other than it doesn't look very pretty close up.
 
Chris A said:
I’m sure this has been asked and answered in this thread but how do you sharpen your knives? What do you use and what grit do you take them to?
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I found that stropping alone with green compound is typically enough if you don't let the edge get really dull. If the edge needs more work, I've been using a Shapton Kuromaku 1000 grit and finish on a strop. I also have a King 6000grit stone but don't use it much.
 
fatfrog said:
I found that stropping alone with green compound is typically enough if you don't let the edge get really dull. If the edge needs more work, I've been using a Shapton Kuromaku 1000 grit and finish on a strop. I also have a King 6000grit stone but don't use it much.
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You might want to add some 2 micron diamond powder or paste. @Oyster asked about the negative effects of using only green compound on D3V, and Nathan replied.

Oyster

Question for the expert sharpeners:

3V is generally grouped with the carbon steels and, like those, responds very well to stropping using regular compounds. At least initially.

My understanding is that the regular compounds (i.e. black and green) will remove the softer material but aren’t able to cut the vanadium carbides. The result is that you get a sharp edge at first but, with continued stropping, the softer material is slowly taken away and the (uncut) vanadium carbides remain without anything to hold them in the matrix so that they easily tear out, quickly leaving a dull edge. For this reason, I remember reading somewhere that diamond paste or other similar compound is better to use as it is able to also cut the hard vanadium carbides - thus avoiding quick/sudden edge degradation as described.

Experiences/thoughts?


Nathan the Machinist

I blend some 2 micron diamond powder into my green stropping shmoo to address that issue


real stropping compound (look at straight razor sites) works better than buffing compound block.


You don't want to build it up too thick, but it does glaze and dull like any abrasive, so I refresh it with a thinned out mixture made with compound and alcohol to mix it up with a finger tip and get some fresh particles onto the surface without building it up.
 
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Personally I do not like most of the pastes and compounds because they are oily and waxy. It works better if it is a soap base that dries into a powder. I guess if you're just doing a few knives it really doesn't matter but I do a lot and I have found a clean powder compound loaded with diamond grit works best. I buy diamond grit off Amazon and mix it into a razor strop compound with a drop of Dawn and isopropyl alcohol.
 
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