TINK, I heard the dreaded noise today

[Ragnarok Forge]

As usual I am fiddling around with new techniques and trying to learn new things.  I was working on interupted quenching a set of skinning knives today and heard the dreaded tink on two seperate blades.  

The technique I am working with is an interupted quench.  The blades are made from modern Heller horse rasps I get from a farrier buddy of mine.  The blades were triple normalized prior to quenching.  I took the blades to nonmagnetic and held them at that temp for 2 minutes each.  The blades were edge quenched in air temp water ( 65 degrees ) to black around 850 to 900 degrees, and then moved to finish quench in 130 degree canola oil. Heller rasps are 1095 steel.   The  bevels, and edges were even, I have the blades in the tempering oven and will take the scale off with vinegar to find out where the cracks occurred.

I have an armguard knife from a prior tink and now, two skinning knives that have small cracks in them.  Being a knife maker so far has meant I never have one of my own knives to use. Every time I make myself a knife someone wants it bad enough I end up giving it up.   I am going to work these knives up, put and edge on them and then use the you know what out of them to see what happens with them over time.  I won't let anyone else have these since they are failed blades.  I figure if nothing else I will get three shop knives out of the blades.

[gudspelr]

I'm sure the moment the sound came was a little bitter after all that work...  But knowing you, I'm sure you'll continue looking at ways to be better at what you do.  I guess like you said, at least you have 2 more knives now.

I don't suppose your Heller rasps are Red Tangs?  Those are the ones I have and have been wondering what steel they are. They 1095, too?


Jeremy

[Ragnarok Forge]

Jeremy,

They should be 1095 if they are from Heller.  You can try to find specific info on the Heller website.  They may list that particular rasps steel type in a catalog.  Another option is to contact Heller directly and they can tell you what the steel type is.  They will either be 1095 or higher carbon steel.

I like to look at the positive side.  As mentioned I have a couple of new shop knives.  Plus I bet they work great despite minor cracks.

[srtben]

sorry too here that! I would personally avoid quenching in water. Unless you are using a lower carbon steel, veg oil is actually a quite fast quench and you'll end up with a lot less tinks and warped blades. Most of the metal sights list 1095 as an oil quench steel. just my 2 cents.

[Ragnarok Forge]

SRT Ben,

Thanks for that info.  I have worked quite a few rasp and file knives sucessfully with canola oil.  I am fiddling with an interupted quench to try getting good Hamon on my blades.  From reading and research a water quench causes cracking when the steel is converting to full martensite at 500 degrees or so.  Hence the interupted quench to oil at 850.  I suspect that having the oil at 130 degrees made it to fast of a quench for 1095 to survive.  My other blades were quenched in my goop.

[Toecutter]

Not an expert on this at all, so I'll stay away from my opinion on what might have caused your tinks using water (more of an oil guy, but i think water temp maybe).
Glad to hear that you dont have a blade for yourself as a knifemaker either. Getting around to a dedicated "me" knife finally after all these years.  This place is full of good info, so I'm sure you'll get a helpful response quickly.  

Good luck, Nathan