O.K.. What about farriers rasps for forging blades?

[Tallbald]

A relative gave me a short stack of dull Mercury brand farrier rasps that he says sell for approximately $20 each new. I tried searching the net to find their carbon content but have had no success. Any input please on rasps as a basis for forged knives? I know that working with D-2 or O-1 would be best , but again, I'd like to work with those materials my great-grandfather might have also had to use. I will also look into leaf springs from a salvage yard--mercy knows we have those here in my area. Thanks as always for input and tolerance, Don.

[Cliff Fendley]

I don't know about forging but I know several guys have made stock removal knives from them. I have some myself I've thought about using.

Some brands are better than others but can't remember the names. If no one here knows you might check on some of the knifemaker forums cause someone there will know for sure. You'll find knifemakers are very willing to help and very sharing with knowledge for the most part.

[Tallbald]

Thank you Cliff. I'll see if any more info shows up. Don

[Advertising]

[Professor Marvel]

Ah My Dear Monsiuer Tallbald -

It has been my experience that rasps and files make fine knife blades, and it seems that rasps are somewhat less brittle than high carbon metal files.

Many if not most modern files are of W1, 1095 or a similar steel. these are suitable for knife making, and have been used
for generations for knifemaking  but one must be aware of several caveats

- file & rasp steel is generally speaking "harder and more brittle" than spring steel, which is "tougher and more flexible".
- if forging, one wants to grind off the large burrs of a rasp, rather than pounding them flat and risk having them "flake off"
- when tempering be aware of the temperature ranges and possible brittleness
- when annealing once more pay attention to the proper temperatures and possible longer "soaking" time required

When making a knife from a rasp, if the file or rasp pattern is left partially intact it lends an interesting"rustic"  look to the finished blade.

Regarding quenching - sticking the work in a bucket of water whilst working it is not really considered proper quenching , that is merely cooling the work to a convenient temperature for handling. Proper quenching is done to harden the finished product,
followed by tempering and final finishing.

There are several kinds of steel, actually manufactured to be quenched in a particular medium - the most common being:
Air Hardening, Water Hardening, and Oil Hardening.

Air hardened steels are more suitable to a high-speed assembly line production environment, and the steel is cooled rapidly in a jet of air. I recall that U.S. WWII bayonets were air-hardened steel.

Water Hardening steels such as W1 (file steel) are often cooled in "softened water", "distilled water", or "salt water".
Most 'Smiths use the special water that comes from the hose. Often a specific water temperature and time is specified in the quenching directions. Water, being a thinner fluid than oil, has a tendency to cool the steel more rapidly. It also has the distinct advantage of being considerably less odiforous than oil!

Oil hardened tool steels such as O1 are to be quenched in a vat of oil of a specified temperature and viscocity. If the viscocity is not correct it can cause the steel to cool to slowly (altering the hardening) or too quickly (often cracking the steel). Additionally the aroma is most amazing (unless olive oil is used - then your knife shop smells like cookies) and occasionally the vat of oil bursts into flames causing great consternation to any adjacent livestock, wives, and eyebrows.


Many ( I might even suggest "most") of the automotive leaf and coil springs are made of SAE 5160 High Alloy Spring Steel

With 5160, as with most oil quenching steels, the drill is in general, Heat to 1600, oil quench, draw by experimental observation 400 - 700.

I have tried forging (and grinding) files,  and both O1 and D2 and found them wanting*  in many ways  in comparison to spring steel due to my "more traditional" blacksmith training.

If one wishes to use only stock removal, the rasps are quite admirable, once annealed. Other smith's I know prefer to forge rasps instead of leaf spring - we all have our preferences.

*(ie: I basically couldn't make the steel do what I wanted, in the manner in which I was accustomed to working
steel. Amongst the issues, the unhappy metal was very "stiff" (hard to hammer), the proper working temperature
ranges were too narrow for my tastes, the hardening and tempering drill was unfamiliar and unforgiving, etc etc etc.
For example: After working VERY hard an entire weekend to forge a rather nice rather large Bowie blank, I "thought
I had it sufficiently annealed. I tossed it onto a concrete ledge and it snapped in half.)

Regarding Family Folklore -
In the past, Successful Commercial Blacksmithing often required closely held secret processes and methods...

much "family folklore" regarding "what my granther used to use" was often based on deliberate disinformation
deliberately diseminated by said blacksmith in order to confound the competition. 'Smiths might also claim to be able to make high quality merchandise out of littlre more than dirt (ie:  bowie knives from scrap nails) in order to inflate their prestige....

They also used to go around to competitors' shops and when no one was looking they would throw a penney into the the forge fire. The burning copper would contaminate the fire and no forge welding could be accomplished until the fire was
cleaned out and rebuilt from uncontaminated coke.

FYI regarding carbon content of common handtools - an old manual from the '40's listed the carbon content
(no mention of any other alloying elements) in some common high-carbon tools as follows:

wrenches: 0.75%
pliers: 0.75%
machinist hammer: 0.95 %
reamer blades: 1.10%
taps: 1.10%
planing tools: 1.15%
mill cutters: 1.15%
twist drills: 1.15%
ordinary files: 1.25%
"saw for steel": 1.60%

thus we can see that files were a good 0.1 % higher in carbon content than common cutting tools,
and "saw for steel" (ie hacksaws) were very high - but (remember the higher the carbon content the more brittle
the implement) - this is why a poorly sparking frizzen on a flintlock is often repaired by  facing said frizzen with a piece of high-grade
hacksaw blade.

hope this helps
yhs
prof marvel

[Tallbald]

Professor your answer is undeniably one of the most delightful and illuminating dissertations I have had the great pleasure to read in quite some time. I shall place it in my bookmarked favorite file , and undoubtedly shall commit it to paper for posterity. Please accept my most sincere thanks and let me express my  hope that in the future I shall in some way be availed the opportunity to reciprocate your kindness. Don

[jefff]

i forged a large bowie knife out of a horseshoe rasp years ago and found it would not heat treat .some rasps are only case-hardened.i suggest you heattreat a sample before you make a knife out of it.jefff

[JimBob]

i forged a large bowie knife out of a horseshoe rasp years ago and found it would not heat treat .some rasps are only case-hardened.i suggest you heattreat a sample before you make a knife out of it.jefff

I've found that true also trying to use one to make a woodworking tool.Rasps in general are made for use on soft material so it seems it follows that they are made of a material suited to that usage unlike metal working files which have to be harder then the material they're used on.I had a disc blade off of a Rome disc like construction companies used for discing rough ground but never tried that for making tools or knives.

[Steel Horse Bailey]

Professor your answer is undeniably one of the most delightful and illuminating dissertations I have had the great pleasure to read in quite some time. I shall place it in my bookmarked favorite file , and undoubtedly shall commit it to paper for posterity. Please accept my most sincere thanks and let me express my  hope that in the future I shall in some way be availed the opportunity to reciprocate your kindness. Don

TallBald - Howdy!

The good Perfesser is one to keep yer eyes on.  His style of "telling" is wonderful to read and his information is Spot-On!  I read ALL his posts I come across on these forums, no matter the subject!

[Professor Marvel]

AH My Dear SteelHorse

you are far too kind to this humble scribbler, your kind words and encouragement are appreciated!

yhs
prof marvel