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Notes From The Edge

AimlessWanderer

Remember to forget me!
No different than a baking sheet, but it might be on longer lol.

I've been trying to remember what he told me and I cant, but 150F keeps popping into my head. I cant grasp the time although I believe it was quite a while and may differ with steel type. I'm sure there will be info out there on some blade making forums though, if not even in this forum.


You can temper a carbon steel blade in a domestic oven, but it will not get it hot enough for quenching
 

AimlessWanderer

Remember to forget me!
Would you do a quick "Tempering and Quenching Basics" for people that know nothing about it please Al? :001_smile
Temperatures depend upon the individual alloy itself, and to be honest I'd have to look them up. This is all from memory, and is just a general guide that might be inaccurate, but gives a very rough appraisal.

Common tool steels such as O1 (the O means oil quench), A2 (air quench), and W2 (water quenched) need heating and soaking somewhere in the region of 750-800C I believe. At that heat the grain structure becomes very fine, and if allowed to cool slowly, the grain size would grow and the steel would become softer. Quenching (in accordance with whatever the individual alloy needs) arrests this grain growth, making the steel very hard. However, it also leaves it brittle.

Tempering allows a controlled amount of grain development, which introduces some toughness back into the structure. This, on carbon tool steels, is done around the 200C mark, and so can be done in a domestic oven. Some stainlesses can be treated the same way, but at different temperatures.

Some steels (typically stainlesses) which are precipitation age hardened, work directly opposite to those described above. Heating to high temperatures and quenching, softens the steel, and leaving to soak at lower temperatures hardens it. That's because on these steels, you aren't manipulating the primary grain structure, as much as the low melting alloying components which lock the molecular structure. Finer grain of the low melting alloys allows more movement of the larger high melting temp molecures, and allowing growth of those low melting temp alloying compounds, leads it to fowm to the voids around the primary grain, locking them in place.

That's a very rough analogy of the two main types of heat treatment.
 
Temperatures depend upon the individual alloy itself, and to be honest I'd have to look them up. This is all from memory, and is just a general guide that might be inaccurate, but gives a very rough appraisal.

Common tool steels such as O1 (the O means oil quench), A2 (air quench), and W2 (water quenched) need heating and soaking somewhere in the region of 750-800C I believe. At that heat the grain structure becomes very fine, and if allowed to cool slowly, the grain size would grow and the steel would become softer. Quenching (in accordance with whatever the individual alloy needs) arrests this grain growth, making the steel very hard. However, it also leaves it brittle.

Tempering allows a controlled amount of grain development, which introduces some toughness back into the structure. This, on carbon tool steels, is done around the 200C mark, and so can be done in a domestic oven. Some stainlesses can be treated the same way, but at different temperatures.

Some steels (typically stainlesses) which are precipitation age hardened, work directly opposite to those described above. Heating to high temperatures and quenching, softens the steel, and leaving to soak at lower temperatures hardens it. That's because on these steels, you aren't manipulating the primary grain structure, as much as the low melting alloying components which lock the molecular structure. Finer grain of the low melting alloys allows more movement of the larger high melting temp molecures, and allowing growth of those low melting temp alloying compounds, leads it to fowm to the voids around the primary grain, locking them in place.

That's a very rough analogy of the two main types of heat treatment.

I enjoyed reading that, thanks Al!:001_smile

Was about to go to bed last night when I thought I would take a quick look at one of the videos you posted earlier Kit. The Scottish Razor Company one, he didn't sound very scottish to me. :001_rolle
Needless to say, I went to bed an hour later than I was intending too.
Fascinating stuff. Thanks for posting it. :001_smile
 

AimlessWanderer

Remember to forget me!
Al, you never cease to impress me.

Ha! Any metallurgists on the forum, will be facepalming at my over simplicity. I've had to have a lot of metalsheat treated over the years. That consisted of me sending out a lump of metal with instructions of what hardness it needed to be, rather than any genuine insights as to how they were going to make that happen :D

Many thanks Al, much appreciated. :thumbsup:

I do need to read it a few more times to "get my head round it," so to speak. :whistling: :001_smile

Sorry if it was a little rambling, Cal. I might have said a little more than I needed to. Blade steels work off the first type of heat treatment.

The second type of treatment is mentioned just to show that now all alloys respond the same way to similar treatment cycles.
 
I enjoyed reading that, thanks Al!:001_smile

Was about to go to bed last night when I thought I would take a quick look at one of the videos you posted earlier Kit. The Scottish Razor Company one, he didn't sound very scottish to me. :001_rolle
Needless to say, I went to bed an hour later than I was intending too.
Fascinating stuff. Thanks for posting it. :001_smile
Compare with the long video from Dovo on their process.


Need Al's view on the the hardening process. It doesn't seem as extensive as the Lewis process.
 

AimlessWanderer

Remember to forget me!
Compare with the long video from Dovo on their process.


Need Al's view on the the hardening process. It doesn't seem as extensive as the Lewis process.

Haven't watched the Lewis vid, but only part of the heat treatment is shown in the Dovo vid. It shows the initial soak and quench, but not the temper.
 

AimlessWanderer

Remember to forget me!
The two knives I made (shown above) both had a cryogenic quench. They were quenched in oil from 800C ish down to 150C ish (hot oil, not room temp). They were then allowed to cool to room temperature, cleaned, and left in a dewar of liquid nitrogen overnight, before tempering the following day. I don't know how improved that makes them over a knife that hasn't had that process, but the knifemaker whose workshop it was, treated all his blades that way, and swore it made a better blade.
 

Esox

I didnt know
Staff member
Maybe give them a longer lasting edge. I dont know how it would affect the outcome of a knife blade either. The results from before and after groups shot with a rifle are pretty clear it does do something.

Screenshot_2019-05-03 Firearms Cryo Barrel Stress Stabilization 300 Below, Inc .png


https://www.300below.com/firearms-cryo-barrel/
 
photostudio_1557083493135.jpg


These two razors, a vintage Joseph Rogers and a Dovo INOX Encina, have been giving me a little trouble this week, chiefly because I have been experimenting with a narrow convex coticule.

The results with the Joseph Rogers were good at first but poor near the heel and when I went at it for a second round really not great at all. It shaved, but badly.

The Encina was a little more successful and a last minute shave before a business meeting on Friday produced an OK shave but one which was not particularly enjoyable.

This morning I decided to deal with both razors and did not want to take any chances.

I dulled both on my favourite coticule bevel setter, (a LPB).

JOSEPH Rogers :
La Petite Blanche bevel set
Dilucot progression with a woody coticule bout
Strop on a pasted hanging strop
Strop on leather
Vintage coticule with clock oil
Strop canvas
Strop leather

Dovo :
La Petite Blanche bevel set
Hard "La Verte". Dilucot progression
Strop on canvas
"La Verte" with water
Pasted hanging strop
Leather strop
Vintage coticule with clock oil

I shaved with the Dovo Encina and it was a superlative shave. It felt like a coticule edge but sharp.

I feel like a fraud progressing between coticules, but it is a sure fire method that works without fail and I don't have to concentrate so hard. A pure dilucot requires a lot of control and concentration. Honing like this doesn't. I can relax and just go with the flow of the honing.
 

Chan Eil Whiskers

Fumbling about.
Sometimes I realize I could get by pretty well with my coticule and its slurry stone. I have at least one super sharp razor honed only with that stone and oil.

With the coticule and the Zulu Grey I'd be set I think as I believe bevel setting is pretty much a snap with the coticule. If the razor weren't quite sharp enough there'd be the ZG.

Another option would be the coticule + pasted strops. Just that would do it.

Maybe not for all razors or all steel, but a guy could get by pretty well I think.

We all know this, or much of it, or a variation of it, and yet here we are.

BOSC.2.Honing allowed in ward 7.jpg


Ward 7 has many inmates. Most don't even know they're in a locked ward and not a rabbit hole. It is very sad.

Happy shaves,

Jim
 

Chan Eil Whiskers

Fumbling about.
View attachment 978195

These two razors, a vintage Joseph Rogers and a Dovo INOX Encina, have been giving me a little trouble this week, chiefly because I have been experimenting with a narrow convex coticule.

The results with the Joseph Rogers were good at first but poor near the heel and when I went at it for a second round really not great at all. It shaved, but badly.

The Encina was a little more successful and a last minute shave before a business meeting on Friday produced an OK shave but one which was not particularly enjoyable.

This morning I decided to deal with both razors and did not want to take any chances.

I dulled both on my favourite coticule bevel setter, (a LPB).

JOSEPH Rogers :
La Petite Blanche bevel set
Dilucot progression with a woody coticule bout
Strop on a pasted hanging strop
Strop on leather
Vintage coticule with clock oil
Strop canvas
Strop leather

Dovo :
La Petite Blanche bevel set
Hard "La Verte". Dilucot progression
Strop on canvas
"La Verte" with water
Pasted hanging strop
Leather strop
Vintage coticule with clock oil

I shaved with the Dovo Encina and it was a superlative shave. It felt like a coticule edge but sharp.

I feel like a fraud progressing between coticules, but it is a sure fire method that works without fail and I don't have to concentrate so hard. A pure dilucot requires a lot of control and concentration. Honing like this doesn't. I can relax and just go with the flow of the honing.

You have so many really nice razors. That Devo is pretty cool looking. I've resisted the SS (other than one GD).
 
Sometimes I realize I could get by pretty well with my coticule and its slurry stone. I have at least one super sharp razor honed only with that stone and oil.

With the coticule and the Zulu Grey I'd be set I think as I believe bevel setting is pretty much a snap with the coticule. If the razor weren't quite sharp enough there'd be the ZG.

Another option would be the coticule + pasted strops. Just that would do it.

Maybe not for all razors or all steel, but a guy could get by pretty well I think.

We all know this, or much of it, or a variation of it, and yet here we are.

View attachment 978209

Ward 7 has many inmates. Most don't even know they're in a locked ward and not a rabbit hole. It is very sad.

Happy shaves,

Jim
Here on B&B there is a bias towards honing, and that's great because it does encourage the likes of you or me to take it up and there is surely something deeply satisfying about make a tool sharp enough to shave just by dragging it across a rock. But we both know how effective pasted strops are and for practicalities sake, a stone and a pasted strop are a good way to get the job done.

I guess I like the purity of honing - and I can get a great shave that way. Sometimes it's just nice to do it the easy way.
 
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