I have some dull farrier's grasps. Rasp on one side and file on the other. I'd like to know how some of you heat treat you rasp 'hawks and knives.

If the rasp is solid steel they are often something like 1090 or 1095 and would be heat treated the same as new steel of that type.  Some of the cheaper rasps are only case hardened and not going to hold an edge well... best to weld in a bit of higher carbon steel for those and heat treat according to the type steel used for the bit.

First thing I do is heat the tang up to non magnetic and quench half of it (the tang) in water.  Put it in a vice (wear safety gear) a inch or so up the tang and see if you can bend it.  A clean break means you're probably working with an all high carbon steel file.  If it bends or doesn't easily break then it may be case hardened.  Case hardened files are for rasp snakes, I wouldn't wast the time making them into knives.  Treat the high carbon ones like 1095 and you should be close.

anneal at approx temp 1550F for  few minutes

cool in vermiculite overnight

heat treat - same as anneal , 1550F for a few minutes

quench in canola approx 125-140F

temp -  425F for 60 , let cool repeat for 60min

 

here's  couple recent ones that are already posted.........good luck with it

 

 

 

working on this one at the  moment.......

 

 

Ah annealing *is* a heat treat, it's just not hardening!

BCROB, those are VERY nice knives.  I especially like the handguard on the bottom one. 

 

I do have to say that the lines on the first one are pleasing to the eye.

BCROB, those are VERY nice knives.  I especially like the handguard on the bottom one. 

 

I do have to say that the lines on the first one are pleasing to the eye.

thank you Mike 

Those first 2 knives are why I decided to try a farrier's rasp knife. Thanks to all of you for the advice. IFI can really be a great resource. Rob the background selection as well as the look of those knives is top notch!

Those first 2 knives are why I decided to try a farrier's rasp knife. Thanks to all of you for the advice. IFI can really be a great resource. Rob the background selection as well as the look of those knives is top notch!

thank you sir , appreciate your compliments..............hope the heat treating tips help you some , good luck , look forward to your pictures !!

First thing I do is heat the tang up to non magnetic and quench half of it (the tang) in water. Put it in a vice (wear safety gear) a inch or so up the tang and see if you can bend it. A clean break means you're probably working with an all high carbon steel file. If it bends or doesn't easily break then it may be case hardened. Case hardened files are for rasp snakes, I wouldn't wast the time making them into knives. Treat the high carbon ones like 1095 and you should be close.

I just did this and WHAMMO!!! Good steel. Snapped off beautifully.

Thank you jmc!!! This one goes in the mental file cabinet!!

jmc, thanks X2 for the info on the bending test.  Sometimes the spark test is not very definitive.

On 11/5/2013 at 9:05 AM, BCROB said:

 

When I quench in oil mine won't harden, but they will in brine.

On 11/6/2013 at 9:05 AM, BCROB said:

anneal at approx temp 1550F for  few minutes

cool in vermiculite overnight

May u email me a pic your heat treated rasp color. I couldn't see them here

email address removed per TOS

Id like to see how yellow the rasp should be as well as a 1095 steel please

BCROB last posted here in 2017; you may have a long wait for a reply!   You do know that digital pictures are unlikely to be the true colour of hot items right?  Now if this is about low temp,  "temper colours", "straw" is a descriptive term.  It's suggest you try something and see if YOU like the results.  For blades I make for myself I often temper differently than for ones made for other people.  (I like being able to sharpen on a good arkansas stone and not need a diamond hone!)

On 11/6/2013 at 11:36 AM, jmccustomknives said:

First thing I do is heat the tang up to non magnetic and quench half of it (the tang) in water.  Put it in a vice (wear safety gear) a inch or so up the tang and see if you can bend it.  A clean break means you're probably working with an all high carbon steel file.  If it bends or doesn't easily break then it may be case hardened.  Case hardened files are for rasp snakes, I wouldn't wast the time making them into knives.  Treat the high carbon ones like 1095 and you should be close.

So I researched the rasps I have and they state they're high carbon. I tried quenching in rapeseed oil but not sure if it was to cold or hot and hasn't hardened. Can I reheat and try quench again?

Yes, you can try again.  If it's not hardenable steel it won't make much difference.  If it does have enough carbon to harden then you may want to try progressively faster quench methods.  However, if it requires something like a brine quench or superquench to harden, then it really isn't good stock for a knife.

Without knowing what quench mediums you have access to it's hard for me to suggest a sequence.   You want to make sure the portion you are quenching is above critical at the time of quenching, and if possible you want the same temperature on every quench.

If it were me I'd try a heated oil quench first.  If that portion did not appear to harden I might raise the steel temperature a little bit and try again.  If it still didn't harden I'd go to water.  If it doesn't harden at that point you can disregard their claim that it is high carbon steel and not waste your time making a blade from the rasp.  If it hardens in water but not in heated oil I'd be thinking it is probably a medium carbon steel at best - and still not a great choice for a blade.

If you are familiar with spark testing you can probably get some idea of the carbon content that way as well.