48-50 rockwall

M

manassas dragon

Joined
Dec 3, 2009
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158
got a call from brad at pht. i sent him a blade that i made from a farrier's rasp. brad heat treated it and called to tell me that it came out with a rockwell near 50. so the question is - should i finish it when i get it back or
chunk it in the waste bin and call it a good experience. in other words is there any degree of usefulness from such a blade?
 
...4140 gets harder than that...

I'm kind of wondering if perhaps the HT isn't right? I mean, surely a tool like that had better hardenability than that?

No - I wouldn't waste much time on a knife that soft. Other than to try a brine quench from a soak around 1525-1550. I know that sounds very hot, but the medium carbon alloy steels like 4150 are austenitized up there and can hit 60 out of the quench.

Otherwise, make a throwing knife out of it?
 
What brand of rasp was it? And what was the heat treatment used to heat treat this? I am with Nathan on maybe the heat treat was not right.

I use a lot of them and I use top quality rasps in my farrier trade. A few years back I contacted many of the rasp makers and was told by each of them with some prying they used 1095.
 
the rasp was a bellota classic that i got from my farrier. he says that they are excellent rasps. i wonder if you just put them in the oven at 400 for a couple of hours and say do that twice if you might have suitable steel for a knife. i have several rasps and i hate seeing them go to waste.

anyway,thanks,gentlemen.
 
I'm going to assume that pht is short for Peters Heat Treat, if it is I would just mark it down as lesson learned and either make a thrower as already suggested or throw it away.
I know nothing about being a farrier but I have many times wondered about the use of rasps for knives. In my mind a rasp is made to cut softer materials such as wood, and in the case of a farrier the hoof of an animal. A hardness of 48-50 Rc is plenty adequate for this. Files are made to cut steel and need to have a higher RC.
Anyway these are just my thoughts as I have never used a rasp for anything other than its intended purpose, take them with a grain of salt.
 
I was just researching this this weekend. I just bought some farriers rasps for making tomahawks. I looked up the rasps (simonds brand) and found the data sheet for them. They have approx. .3 % carbon. About the same as a railroad spike. Neither will make a very good knife, but they are excellent for a wrap and weld tomahawk with a tool steel bit welded between. Makes sense, since these rasps are used on horses hooves that they don't need to be ultra-hard.
 
If at all possible its best to heat treat a small piece of an unknown rasp if possible..That way you will know for sure..
 
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