What did you do in your shop today?

[Charles dP]

Damn. Sorry for your loss Gerhard.

[Joshua States]

Sorry about the loss of a good friend Gerhard.

 

Today I had a little time to work on some stuff. I took these three blades to 220 grit after HT.

The top one is a 9-inch chef in 1095, (pre-sold) the bottom one is a very complicated commission for an O1 EDC that has me pushing the envelope on my handle skills, and the middle one is a small 4-inch, wide-blade hunter/skinner that I made out of the first try at the commission blade. It cracked in the quench. I knew the oil was too cold and tried the quench anyway. Stoopit me.

 

 

[Joël Mercier]

42 minutes ago, Joshua States said:

knew the oil was too cold

Could you please elaborate? I didn't know it could do that. I thought colder oil was slower, hence safer.

[Joshua States]

17 hours ago, Joël Mercier said:

Could you please elaborate? I didn't know it could do that. I thought colder oil was slower, hence safer.

Wouldn't we be recommending that people quench in ice water if that were the case? Why do we pre-heat quenchants like canola oil? I am going to step out on a ledge now and invite Jerrod Miller to push me off of it.

What we want from our quenchant is the optimal rate of heat transfer to get to the martensite start temp (Ms) quickly enough to ensure a good phase transformation, and work slowly enough to ensure as near to complete transformation as we can get.

My understanding is this is the underlying theory behind both cryogenic tempering and marquench-tempering. Get the hot steel "past the nose" of the Ms curve quickly and then prolong the cooling in that state to get a much fuller transformation.

I may be totally wrong, but from what I do know of O1, it doesn't particularly like a really fast quench. It is designed to through-harden and its optimal quench rate is considerably longer than what water or a fast oil will allow. I have had success using a fast oil before, but back then I was preheating my oil to 120*F before quenching. On this particular day, it was about 60*F in the shop and the medium speed oil was probably much cooler than it was designed to work at. So I dunked my hot O1 into a very cold oil and the resulting rapid transformation caused too much stress in the steel.

[Jerrod Miller]

The goal of a perfect quench is to cool as slowly as possible while still achieving one's goals.  In the case of of hardening steel, if one wants as much martensite as possible (it is debatable if this should be the goal) then the goal is to completely miss the nose of the TTT curve and get to the Ms temperature.  Since the TTT is indeed a curve, this means while we have to cool rapidly at first to get past the nose of the curve, once we are past it we can slow down our cooling rate while still achieving our goal of getting below Ms before crossing the curve.  As noted in the recent stainless/cryo thread, the rest of the cooling below the Ms to Mf can be complicated (maybe fast is necessary, maybe not).  Conventional wisdom has been that once you are below the Ms temperature, rate of cooling was not important to the completion of forming martensite, so you might as well go slow to minimize stresses.  

 

Engineered quenching oils (or polymers, meaning Parks 50, AAA, etc.) are designed to have a cooling rate that is quick at the beginning and slower at lower temperatures.  These oils require a specific temperature range for the oil itself to perform "as designed".  Non-engineered oils also perform differently at different temperatures.  Generally speaking, cooler oil temps mean slower cooling in that initial phase of the quench, so you may not miss the nose of the curve and start forming pearlite or bainite before getting below Ms and the rest goes to martensite, but lower stresses and less likely to crack.  The heat transfer of all quench oils are curves, with a cooling rate as a function of steel temperature; and the curve changes to some other curve that is also a function of temperature (just a different function).  Water is a bit different in that we end up with a vapor barrier when the water gets to 212F.  If your water starts at 70F, you are only 142F away from boiling.  If you start at 33F you are 179F away from boiling (a difference of 26%).  The main factor of concern in a water quench is not the cooling rate of the water, it is how much cooling you can get done without the vapor barrier being a big factor (problem).  On top of that, it isn't the vapor jacket in itself that is a problem, it is the non-uniform cooling due to a non-uniform vapor jacket.  With large enough parts, a vapor jacket in a water quench is close enough to uniform that you can use hotter water as a slower quench.  For example, you can quench a couple tons of 4330 in 120F water (with adequate circulation) and it will act more like an oil quench, where if you start with 70F water the quench will be too quick before the vapor jacket forms and the parts will crack.  

[Joël Mercier]

So, in other words, the colder oil isn't likely to be the culprit? 

 

Btw Joshua, I didn't want to sound like a smartass, I was genuinely curious about it. 

[Jerrod Miller]

1 hour ago, Joël Mercier said:

So, in other words, the colder oil isn't likely to be the culprit? 

IIRC Joshua uses Parks 50.  I never have used it nor looked into it too much.  I think it is only slower at cooler oil temps, but the cooling curve may be erratic when it isn't pre-heated to where it is supposed to be.  It is also possible that the shock of going from 1475 F (or whatever Joshua is using) to 60 F was just too much for the steel compared to 100 F.  But that is a difference of 1415 vs a difference of 1375 (about 3% change), so I would be surprised.  

 

Here is Larrin's article about it (I only briefly scanned it, but what I saw seemed pretty relevant to this).  

[Joël Mercier]

48 minutes ago, Jerrod Miller said:

ere is Larrin's article about it (

I find that article a bit odd, as if Larrin thought makers actually quench their carbon steel blade at full thickness. Especially when he says he finds it odd that new makers use 1084 with canola because his results show poor hardness. Well, if you don't quench your blades with 1/8" thick edges it's suddenly less odd . 

[Joshua States]

2 hours ago, Joël Mercier said:

So, in other words, the colder oil isn't likely to be the culprit? 

 

Btw Joshua, I didn't want to sound like a smartass, I was genuinely curious about it. 

I totally got that, and I didn't want to sound snarky with my response either.

 

35 minutes ago, Jerrod Miller said:

IIRC Joshua uses Parks 50. 

For everything other than O1. For my O1, I use a medium speed quenching oil whose manufacturer I cannot recall. It appears to work better with the O1 and produces a harder blade than the Parks did, but I might be imagining that. I switched to this oil after multiple quench failures in Parks 50 with a hollow ground O1 blade. Alan suggested I use a different quenchant, one that was not as "fast". I had this stuff sitting in barrels for a few years and started using it for the O1. I usually don't have to heat it up, because the ambient temp in my shop is typically above 80* F. This was a cold day and I developed a small crack on the edge. After heating the oil to about 110*F it worked fine.

[Gilbert McCann]

From an 8lb sledgehammer to 5.77lb hammer. Forged an integral with a new friend last week and thought I would copy his hammer and make it a little lighter (his 6.5lb mine 5.77lb)

[Matthew Biondi]

Not technically today, but very recent! The forging was done quite a bit ago, and my hammer technique is better now. The guard and scales were just the other day. I'm pretty happy with how this one is turning out. Still some finishing work to go, planning on getting it done this week. Found out the heat-treat wasn't perfect during some harsh testing, but I think I've patched it up by changing the geometry a bit so it's thicker behind the edge. 

[Garry Keown]

I got a few blades finish ground today and then decided I needed an addition to the kitchen knives patterns.

My largest chef knife is just 7 1/2 and I know that there are longer knives both on the market and that other makers are offering so decided to work on a pattern for the K tip but with a western handle as many have done that arent tied up in the absolute tradition of some designs.  I just cant get to like the japanese handle that sits above the spine of the knife so with that said I got a sheet steel pattern done with a 9 in blade ( I think I may increase the length to 9 1/2 or 10) and transfered it to a bar of 14 layer carbon damascus that I had bought in for an order that never eventuated.

This is where this one will start. I have a length of black zebra bone for bolster but not sure what I will do the handle with as yet. 

[jake cleland]

Got the knotwork hamon polished last night and took it out of the coffee etch this morning;

 

[Brian Dougherty]

That is pretty wild Jake!

[Alan Longmire]

Ooh, I like that!

[Rob Davis]

Annealed a bunch of files and shaped a few too!  

[Brian Dougherty]

Well, I finally lit the forge for the first time in about a year.  Hopefully I am back at it.

 

I struggled and failed at keeping the twists even., but I'll push forward to see what happens next. A coal forge would be nice for selective heating.  

Edited February 27, 2022 by Brian Dougherty

[Kreg Whitehead]

I just picked this wagon tire up....guess thats what you would call it.

I dont really want to cut it up if its not wrought....my co worker said he would take it for the 20 bucks I just paid.

I guess just buy a flapper disk for my grinder....get to clean steel....and roll it into some vinegar.

I have been out of ferric for a while.....any other thoughts or suggestions?

Here is a dagger I started and finished the weekend before last.

It was a commission piece for someone my boy works with. I am hoping its going to lead to some referrals....most everyone at that shop is into blades and so is the boys family.

The steel is some 5160 I bought for 6 bucks a pound from a local spring shop and the wood is kingswood per customers request.

[Alan Longmire]

11 minutes ago, Kreg Whitehead said:

any other thoughts or suggestions?

 

Has it got any really rusted spots where you can see a sort of elongated grain pattern, kinda like driftwood? Here's an extreme example of this:

 

 

On wagon tire it has to be pretty rusty to show up through the pitting.  It tends to show better on the inside surface than outside, since use compresses the iron on the working surface.  Personally I haven't found vinegar to be of much use on wrought.  Got any muriatic?  Concrete cleaner?  Swimming pool PH-down?

[Rob Davis]

Annealed a bunch of files.  Started shaping and grinding!   

 

Edited February 28, 2022 by Rob Davis

[Faye]

After wrangling a stray alignment pin back into place, I got the handle shaped and sanded today, but forgot to get a picture before I took the guard off. I'm really excited for this one to be done. It should be a slicer, with a 0.095 spine, a zero edge, and something like a convex grind. I'm messing around with different geometry than I'm used to, we will see if it works.

[Garry Keown]

Ground post heat treat on a  low layer count damascus blade fresh out of the coffee soak with a wd40 coat to protect it. 

 

[Kreg Whitehead]

19 hours ago, Alan Longmire said:

 

Has it got any really rusted spots where you can see a sort of elongated grain pattern, kinda like driftwood? Here's an extreme example of this:

 

 

On wagon tire it has to be pretty rusty to show up through the pitting.  It tends to show better on the inside surface than outside, since use compresses the iron on the working surface.  Personally I haven't found vinegar to be of much use on wrought.  Got any muriatic?  Concrete cleaner?  Swimming pool PH-down?

Unfortunatly I am not seeing much of any pattern. I can pick up some muratic. I assume I am gonna wanna dilute that down pretty good.

[Alan Longmire]

12 minutes ago, Kreg Whitehead said:

I assume I am gonna wanna dilute that down pretty good.

 

Nah, not for testing wrought.  It's already diluted down to around 30% when you buy it.  Just don't leave it in the shop.  The vapors will rust everything overnight, even with the bottle closed.  

 

Fun fact: If you keep adding iron to it until it no longer dissolves it, it's now ferric chloride.  That you do dilute.  How much depends on the original strength of the acid.  I'd go 5:1 water to homebrew FCl.  

[Joshua States]

9 hours ago, Alan Longmire said:

Fun fact: If you keep adding iron to it until it no longer dissolves it, it's now ferric chloride.  That you do dilute.  How much depends on the original strength of the acid.  I'd go 5:1 water to homebrew FCl. 

I have voiced this and was corrected by Matt P.

He told me "This makes Ferris chloride, you need to add hydrogen peroxide to convert to ferric, go slow in an over large container. This is an energetic reaction. The Ferris will be a green color, add peroxide until it turns brown, and it is ferric, add distilled water until it etches nicely.  This works well as an etchant, but I have found ferric made this way is not as stable as store bought."

Never having made this myself, I cannot comment one way or another. I leave that to someone with more chemistry knowledge than me.

Edited March 2, 2022 by Joshua States