O-1 Knife making plan...

W

WealthyCow

Joined
Jul 14, 2017
Messages
3
Hello, sorry if this is a repost, but I want to get a confirmation that this knife making plan would be okay for my intended use before I do it.

This would be for a generally more rough use camping/bushcraft/survival knife (around 4" blade) where chopping is a possibility, but I would most likely have a hatchet on me.

-Grind bar stock to blank
-File bevel to dime thickness (scandi grind)
-Rough polish to 220 grit
-Normalize three times (to account for stresses from grinding and/or imperfections from the mill)
-Soak knife blade 10 mins at ~1500 F
-Quench vertically in heated canola oil that is 125-150 F

One main question is on tempering for this specific type of knife. Should I oven temper at 400 F for two hours, two times? 450 F? Three times? Should I oven temper twice, then soft back draw? Just soft back draw? Would a soft back draw be beneficial for this type of knife?

-Polish knife to satin finish at 600 grit
-Sharpen on whetstones

Thank you for your input and time.
 
Stock thickness is 1/8" and metal supermarket. Is the soft back draw not something worth doing with O1? I've heard that people recommend 425F-450F for rough use knives.
 
The O1 sold by my supermarket is by Buffalo and has no Vanadium

consider Starrett

-not that it makes much difference.
 
scott.livesey said:
what is stock thickness? where did you get the steel? most O1 is properly annealed by the maker and needs no normalize cycles. 10 at 1500F should be ok. best results is temper at 375-400F for 1 hour, cold water quench, then 375F for 1 hour. for O1 your best hardness/toughness is at Rc61-63 (https://www.crucible.com/eselector/prodbyapp/tooldie/ketos.html) if you want softer, choose a different steel.
Click to expand...

Are you sure about this?

I pre heat to 1200 for 10-20 min, then ramp to 1475, and soak for 10 min. Quench in medium speed oil (canola works fine) and temper to desired harness. http://www.cashenblades.com/steel/o1.html

My blades come out exactly as per this chart.
 
WealthyCow said:
Stock thickness is 1/8" and metal supermarket. Is the soft back draw not something worth doing with O1? I've heard that people recommend 425F-450F for rough use knives.
Click to expand...

Don't mess with soft back temper. Go with Rc60/61 and get the most out of your blade. It's plenty tough at Rc60/61, unless you are making a jackhammer bit, or pry bar.
 
Pre-heat at 1200F for 10-30 minutes,
Austenitize at 1475 for 10 minutes,
Oil quench in medium speed oil
400F double temper. Water cool between tempers.
Final hardness should be Rc 62
 
going by recommendations from Roman Landes on another forum(http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=616&hilit=1.2519&start=10). His thought is get furnace up to temp, get the blade in, minimum soak then get the blade out.
"Austenit forms already at 750°C
You want the heating speed as fast as possible so you put it in the firmly preheated oven.
Heating speed also counts for Ausgrain.
But for stock removal blades the material shall come with a proper micro structure, perfect for hardening.
Just go straight for the oven with 800°C.
Abour the tempering Temp. if you do have the request for a more tougher edge, the correct lever is the carbon content and alloy content, respectivley.
But, it is not the tempering temperature.
Recommended tempering for those steels in knife applications, should be carried out in the range of 170-210°C.
The reason is the lower toughness (blue brittleness) in the range of (200 °C < T < 400 °C)."
A pre-heat would work i guess if you had two furnaces. the ramp time from 1200 to 1475 may cause more issues than it solves.

 
Stacy,

What does the preheat do metallurgically? Is it for stress relief? To prevent heat shock?

I have read the "Steel Metallurgy For The Non-Metallurgist" book which was extremely helpful.

Thanks!

Mike
 
scott.livesey said:
going by recommendations from Roman Landes on another forum(http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=616&hilit=1.2519&start=10). His thought is get furnace up to temp, get the blade in, minimum soak then get the blade out.
"Austenit forms already at 750°C
You want the heating speed as fast as possible so you put it in the firmly preheated oven.
Heating speed also counts for Ausgrain.
But for stock removal blades the material shall come with a proper micro structure, perfect for hardening.
Just go straight for the oven with 800°C.
Abour the tempering Temp. if you do have the request for a more tougher edge, the correct lever is the carbon content and alloy content, respectivley.
But, it is not the tempering temperature.
Recommended tempering for those steels in knife applications, should be carried out in the range of 170-210°C.
The reason is the lower toughness (blue brittleness) in the range of (200 °C < T < 400 °C)."
A pre-heat would work i guess if you had two furnaces. the ramp time from 1200 to 1475 may cause more issues than it solves.
Click to expand...


800c=1472f.
 
It helps the blade enter the austenite stage with no stress. This helps prevent warp and such.

I am sure an O-1 blade will be fine if just placed in a 1475F oven, but pretty much all standard HT regimes I have seen published call for steels with higher amounts of alloying to be pre-heated - O-1 has four times as much alloying as it does carbon.

I think most all commercial knifemaking HT ovens will ramp from 1200 to 1475 more than fast enough to avoid any worry about grain size changes in O-1 steel.
 
So, similar to a 1200 F x 1 hour stress relief cycle. I was wondering if commercial recommendations for preheats weren't based on industrial ovens that can ramp much faster than what the average hobbyist owns. It takes 10-15 minutes to get from 1200 F to 1475 F in my oven from a cold start, during which I assume the steel has some stress relief/buffering from thermal shock effect. That assumes starting with cold steel in a cold oven vs placing cold steel directly in a hot oven.

Maybe I'll mess around with this someday as I side project with all my free time.

Thanks!

Mike
 
The industrial charts also are dealing with steel mass hundreds to thousands of times greater than the mass of a knife blade. That is why I said it should not be an issue whether you do a per-heat step or not.

I just like to get the blade evenly heated before it crosses the Ac1.
 
You must log in or register to reply here.
Back
Top