Getting started on a 52100 wa gyuto, advice appreciated

DeadboxHero

DeadboxHero

Knifemaker / Craftsman / Service Provider
Joined
Mar 22, 2014
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Hey guys,

I want to make a Wa Gyuto.

My plan is to cut out with a angle grinder.

Heat with a MAP torch on some refactoriy bricks, heat to bright cherry/orange hold and feather for 5minutes. Quench in warm(80°f) canola oil.

A few questions.

Would a 1x30 with high end low grit belts be faster then an angle grinder? Also I was looking at a benzomatic cutting torch for faster heating?
Do I let the steel cool to the oil temp during the quench?

Is the stock thickness too thin for a Wa handle?



Thanks bros

Shawn
 
You can profile this thin 52100 easily via a hack saw + 1x30 36grit ceramic belt. Angle grinder is over kill (and unnecessary risks).

As bought is 0.052" - will be thinner than that as finished, so it's might be too thin for a gyuto WA handle.
 
52100 is a very tricky to heat treat and can certainly not be done well in a teo brick forge. It needs a long, controled soak and fast quench oil. Send it out, or use another steel.
 
Shawn that is thin to start out with. Even some paring knives are thicker than this .052. I like thin but that's a bit too thin for a Gyuto IMO


Sent from my iPhone using Tapatalk
 
Thanks for the help guys.

Saves me heartache

What's a good thickness for a Gyuto? .150?
 
At that thickness, you are probably going to have warpage issues even if you grind after heat treat.

I would go with .125" or .100". By the time you grind it, the blade should be even thinner.
 
Thanks again.

Guess it's nakiri time!



I used the hack saw ,thanks blunt cut



As far as heating goes would a blow dryer and coal system work better? I don't have the power, space or resources for an even kiln.

Also is parks 50 only sold in 5 gallon buckets?

Thanks guys for your help.

I'll order some better sized bar stock in 8670 or 80crv2

Shawn
 
Shawn - that $2 kiwi is a very tough challenger to your 52100 nakiri. I've sharpened plenty of those Thai's kiwi veg nak.

To get a fighting chance, I would rather use a 3/4" mini torch. Heat w/ brush strokes about 0.5" above edge (avoid over heating). In a dark room, use high heat until just past decalescence, Continue to heat up another shade of red using lower heat. Try to keep at that shade for a minute or so (OK, this is for AKS 52100 not Aldo). Quench in warm canola with rigorous chopping motion back/forth for 5 seconds. Take out. Straighten your warp with 3 points via hand and or plier. Air cool. Wash. Toss in freezer for 10 minutes. Wash. Use a file to test hardness. If skated, temper, else repeat aust with a bit brighter red color.

Coal/charcoal & blower & pipe muffle will work too but harder to judge color and or magnetic check.
 
bluntcut said:
Shawn - that $2 kiwi is a very tough challenger to your 52100 nakiri. I've sharpened plenty of those Thai's kiwi veg nak.

To get a fighting chance, I would rather use a 3/4" mini torch. Heat w/ brush strokes about 0.5" above edge (avoid over heating). In a dark room, use high heat until just past decalescence, Continue to heat up another shade of red using lower heat. Try to keep at that shade for a minute or so (OK, this is for AKS 52100 not Aldo). Quench in warm canola with rigorous chopping motion back/forth for 5 seconds. Take out. Straighten your warp with 3 points via hand and or plier. Air cool. Wash. Toss in freezer for 10 minutes. Wash. Use a file to test hardness. If skated, temper, else repeat aust with a bit brighter red color.

Coal/charcoal & blower & pipe muffle will work too but harder to judge color and or magnetic check.
Click to expand...
Yea those kiwi knives are awesome.


[YouTube]cc9aBcDWnrU[/YouTube]

Here a video I took getting the steel even.

I then feathered it for 5 at a reddish orange.

Quenched in warm canola I heated on the stove top to a warm temp.
I transfered fast.

No flame on quench

I held it in one place during the quench and left in until cooled to the oil. (30-40 sec)




Slight warping fixed in vice.



File checked good.

Didn't read your post in time for the freezer option Bluntcut
:(

It's in the oven at 400.

I'm so nervous. Yet excited.

None of my knives have turned out great.
 
Using edge of file to test again for skating, again. Stationary quench most likely sub-par/failed in this case.

At ~1475F vapor jacket will be prevent sufficiently fast cooling to avoid pearlite nose. Here what vapor jacket for 1000F aluminum rod stationary quench in water look like.
https://www.youtube.com/watch?v=hhB2sBD3GlU

I could be quite wrong as well :D
 
Hahaha dammit. So much to learn.

Thanks Bluntcut

I really appreciate your time.
 
Bluntcut,

I think it might have worked

Sharpens and cuts decent.

 
Vegetable oils like canola don't suffer vapor jacket issues. Is this still 52100? If so, canola oil will be plenty fast enough unless you do something to generate extremely fine grain sizes.

Edited to add:. That small container may cause trouble due to small volume but it it holds an edge you likely got what you were after.
 
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DBH, you'll like 52100 done well ;)

Bluntcut might be wrong about canola but he's done his homework a lot around 52100 his pointers would be useful :thumbup:
 
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That thin 52100 would have been nice forge welded between 303 stainless lol

Lookin good keep going.
 
LOL IME - I've seen plenty of under surface bubbles when quenching in P50; canola and other oils in large quench tank + agitation. Vapor/smoke bubbles are present. Just heat up a 3/4" dia steel rod to 1500F, then dip into a jar of oil w/o agitation(like Shawn did) - you will see the jacket. Oil conductivity is extremely slow w/o movement - http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html <= canola could be a tad higher value than olive oil. That said, I open for learning otherwise ...

Shawn's nakiri might worked because of very thin stock and large contact surface.

edit to add: interaction between 1500F and liquid medium with vapor point in 450F range will generate convection bubbles. bubble size grow/collapse depends on property and fluid dynamic.
 
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Luong,

Sorry, you have seen more definitely. :o

Just saw the video linked and got me thinking.
Won't be a bubble (past boiling point) means the liquid actually absorbs more heat? Or that when heat is transferred into vaporizing the liquid & bubble leaving the metal surface and new liquid comes into contact actually helps cooling?

If it indeed reduce the cooling speed, then it means heat transfer without boiling is more effective?
 
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Chris - no worry & thanks for your supported words.

Heat transfer is very complex however in simplify view of non-solid... The temperature gradient & fluid+aero dynamic are 2 key drivers. Lower viscosity liquids usually have higher thermal conductivity than high viscosity and definitely lower particle density in vapor form. Liquid to vapor indeed absorb/require large energy (hey, sweat w/o evap = soggy/muggy hot :)), a standing layer of vapor/air lowered heat transfer rate due to air+density of particles (going from smoke to fire to molecular chain break down). Convection is a heat conveyor, which induce fluid/aero dynamic but still very slow compare to move hot objects to area of higher temperature gradient and while collapse & keep vapor jacket to minimum or none, via agitation/chopping motions when quench.

Chris "Anagarika";16126755 said:
Luong,

Sorry, you have seen more definitely. :o

Just saw the video linked and got me thinking.
Won't be a bubble (past boiling point) means the liquid actually absorbs more heat? Or that when heat is transferred into vaporizing the liquid & bubble leaving the metal surface and new liquid comes into contact actually helps cooling?

If it indeed reduce the cooling speed, then it means heat transfer without boiling is more effective?
Click to expand...
 
Yes there is vapor, but it isn't a jacket that must be breached or collapse. When I get to my desktop I'll link the study on using vegetable oils as a base for industrial fluid for quenching. It's not the only one, but it's the only one I've read recently. One reason to use them is the faster initial cooling rate as they tend to skip the vapor jacket phase of cooling during quenching. They have less chance of warp as the cooling is more even than if a vapor jacket is present.
 
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