The ubiquitous Harbor Freight Fireman's hatchet mod

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Jul 19, 2019
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after seeing a number of people modding the harbor freight fireman's hatchet into a camp axe, small forest axe, Gränsfors Bruks want-to-be, I decided to give it a try. It is not really going to be a how to as there is plenty of that for this. it is just going to show my version of the mod

to start, the hatchet in stock form.
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I welded some bolts to the circular steel wedges, with a little contraption, pulled them out
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this is the approximate area to cut out along with removing the spike
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after cutting it and cleaning it up on my belt sander. I also thinned it out a bit. sorry I forgot to weight it before reinstalling the haft.
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here it is complete
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I was planning on re-heat treating it to try and get more potential out of the steel, but when I started grinding on it I discovered that it is actually cast steel. upon heating it to just beyond blue and letting it cool it still hard and a file didn't cut any easier. so I left it as is.

Well I hope you enjoy
 
Those are interesting and I think you did a nice,clean job of snipping the spike off of it and pulling mass from the underside! Also, those are nice process pictures of pulling the barrel wedges.
 
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I was planning on re-heat treating it to try and get more potential out of the steel, but when I started grinding on it I discovered that it is actually cast steel. upon heating it to just beyond blue and letting it cool it still hard and a file didn't cut any easier. so I left it as is.

Just curious...what makes you think it's cast steel?
 
Good job!

And 42 has just beat me to exactly same question:)

Also,IF indeed so,i wonder if HT would differ materially...
(All steel has been cast as an ingot that is then rolled to whatever shape,the difference in the lattice is mechanical in nature...i think...).

You must've ended up with a few small cut-offs(unless you ground that all of),those may be really handy for learning about that specific alloy.
One test that is rather constructive is for grain size;by trying to bust it in the vise as is,or hard-quenching it first(a quick heat to critical shouldn't affect original grain size too much).
The next test would be to see how susceptible the alloy may be for grain reduction by normalizing...(may save a lot of headache later).

Also,just running any of the oxidation colors on the surface may not represent the state of given alloy in it's Mass;the oxide layer that we see as "color" is in itself just a few thou.

HB products are Such mystery that they can be Anything,either hard or soft,and of Any imaginable alloy...No number of most thorough backyard testing could ever answer All questions nor answer them with anything approaching certainty...But still,curious.

Again,good work,and all above strictly academic.
 
My first clue, other then purely the look of it, was the hot hardness. Then as I started cutting it the sparks, then the smell. I don't know if anyone else can smell it but whenever I grind cast it always has a unique smell. Then she small dark grey powder grinding dust

I do have some of the cut offs, such as the large spike left over. I'll chenk on the grain structure and see if it responds to any kind of hardening
 
My first clue, other then purely the look of it, was the hot hardness. Then as I started cutting it the sparks, then the smell. I don't know if anyone else can smell it but whenever I grind cast it always has a unique smell. Then she small dark grey powder grinding dust

I do have some of the cut offs, such as the large spike left over. I'll chenk on the grain structure and see if it responds to any kind of hardening

None of those things would inherently indicate that the steel had been cast. There are grades of tool steel that are able to be cast, but cast steel still has grades and they all behave differently, like other steels. Cast steel isn't the same as cast iron.
 
Hm...Thanks,and just in case,you Do know that there's a considerable difference between Cast Steel and Cast Iron?

Cast iron,by definition,has Over 4% Carbon.That being way too much over what can go into solution,is extruded into the intragranular spaces,in the form of graphite or other form of C(we won't go ito all that,but your basic diff between "white" and "grey" et c.).

On hammer/vise testing Cast Iron will fly apart Very readily(because the molecular bonds are weakened by those inclusions;btw,it is so on purpose,for stability of mat-l).

Cast STEEL,conversely,is just steel alloy that has been brought to liquidus and then...whatever.Your normal arc-weld is technically cast steel.It's malleable,and shares most other qualities with rolled steel,et c.
(just for giggles,all of That:)
 
I was planning on re-heat treating it to try and get more potential out of the steel, but when I started grinding on it I discovered that it is actually cast steel. upon heating it to just beyond blue and letting it cool it still hard and a file didn't cut any easier. so I left it as is.

Well I hope you enjoy
Why were you considering re-heat treating it ? They are pretty decent heat treated to start with . The cutting edge is harder than both fiskars hatchets and estwing hatchets yet you can cut the spike with a sawzall. The European style axe heads aren't my thing so I thinned out the edge , cut the spike off and thinned down the handle a little. I am impressed with the steel in harbor freight hatchets for the price. I have 2 of the plastic handle hatchets that I bought for beaters/loaners and was pleasantly surprised when I went to put an edge on them. That is part of the reason I picked up the firemans hatchet to mod
 
Why were you considering re-heat treating it ? They are pretty decent heat treated to start with . The cutting edge is harder than both fiskars hatchets and estwing hatchets yet you can cut the spike with a sawzall. The European style axe heads aren't my thing so I thinned out the edge , cut the spike off and thinned down the handle a little. I am impressed with the steel in harbor freight hatchets for the price. I have 2 of the plastic handle hatchets that I bought for beaters/loaners and was pleasantly surprised when I went to put an edge on them. That is part of the reason I picked up the firemans hatchet to mod

because I can't leave well enough alone. as much as I would like to trust the heat treatment from an axe that cost only $20 I can't. I wanted to anneal it to make it easier to shape, cut, grind, etc. then re-harden it and temper it back where I wanted as it looked like it is hard all around and not just the cutting edge
 
so I rehardened a piece cut off and broke it to look at the grain structure. it actually looks quite good to the naked eye. took some macro shots for you to see. it makes it look worse then it is. the piece is about 7/16" wide as shown by the ruler. after quenching it a file skated right off of it. another piece I let slowly cool and it was still hard where a file bearly cut into it. the third piece after quenching I heated until blue and it felt just as hard as the slow cooled piece

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I also spark tested it on my bench grinder which likely gives better results then the cut off wheels I am using
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looks like a high carbon steel, possibly some kind of tool steel. I guess you guys were right. I didn't give this steel enough credit. maybe it is some kind of high speed steel?
 
Thanks for the photos,,Backyard.
I'm struggling with my reception and can't see the grain photo yet.

Meanwhile,as far as spark:The most usefulness this method offers is as analog testing.Machinists used to keep a small selection of tabs of different alloys all on a chain together next their bench grinder.
So you're on the right path.
Your description harkens indeed to something HSS-ish(not that Any of this could ever be called with certainty).
Try a sample of HSS(any old drill-bit or whatever)to compare.
A file makes a handy analog for plain-carbon steel;leaf-spring for med.-carbon Cr based alloy,and so on.Try comparing till the likeliest match occurs.

Asfar as hardness testing with a file.
Straight up,as in filing the edge or whatever,feels right intuitively but is actually misleading(in it's inaccuracy in principle).
You can indeed,(kinda-sorta)feel the difference between an A and a B alloy by using same file with same effort et c.In actuality it's illusory.

What file test Does work for is only softer/harder than file itself.That's it(but it's something;albeit useful only on as-quenched alloy,nothing else is usually harder than a file).
Testing is done not with file teeth,but by attempt to scratch as deep a groove as you can,with a Virgin corner of a Known file.

By no means i want to claim some ultimate truth in these matters and you must forgive my sometimes hectoring,categorical tone.English as a Second Language is my usual excuse:).
 
Ok,i see the photo of the break,you've done a great job photographing it.
No,grain-size that large is not acceptable for a tool such as an axe(at least not Desirable that's for sure).
I realize it's magnified but the individual grains Are visible,by the naked eye,and they oughtn't be.
What it may mean is not that certain.I know nearly nothing of HSS,nor of many other alloys it may be,or you may even be right about it being a casting.

If it was me,and i was up against having to use this alloy for a tool,next step would be to see if it's susceptable to grain-reduction by Normalizing.
That involves heating it 3 times,first to just over-critical,then to just crit.,and third time to just below crit.
After each heat letting it cool in still air till black(lack of any invisible)heat.
Then quench again,and make another break.

Now here's the thing about grain-growth:It is a function of being held for long periods at high heat.So after repeated forging heats et c.,right before HT it gets normalized,and all's cool.
But here's the rub.One very important aspect of quenching is Soak-time(at critical T).Each alloy has it's correct time,say plain-C alloys it's 1-1.5 minutes.But for say O1 it's about 30 minutes...
Exceeding this time causes the grain to enlarge(not soaking it enough does not convert enough of the structure to what you need it to become).
Excessive T also causes grain to grow.

So sometimes after normalizing properloy one can screw it all back up by incorrect T and/or soak-time at quench.
(junk alloys are rough to play with,after a while you'll just want to buy a legit,Known alloy,it saves So much hassle!:)
 
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P.S.
I do believe most alloys that we refer to as "HSS" are air-hardening;that would be consistent with it not loosing much hardness when heated to whatever you had it up to.
 
I was thinking about doing exactly as you mentioned with various known steels.

With the file, I totally understand about the hardness. I was testing more for: did it harden and if I got it hot did it soften any.

And because of it's hot hardness capabilities is my guess at the HSS. I will do more spark tests later and see what I find
Thanks for the photos,,Backyard.
I'm struggling with my reception and can't see the grain photo yet.

Meanwhile,as far as spark:The most usefulness this method offers is as analog testing.Machinists used to keep a small selection of tabs of different alloys all on a chain together next their bench grinder.
So you're on the right path.
Your description harkens indeed to something HSS-ish(not that Any of this could ever be called with certainty).
Try a sample of HSS(any old drill-bit or whatever)to compare.
A file makes a handy analog for plain-carbon steel;leaf-spring for med.-carbon Cr based alloy,and so on.Try comparing till the likeliest match occurs.

Asfar as hardness testing with a file.
Straight up,as in filing the edge or whatever,feels right intuitively but is actually misleading(in it's inaccuracy in principle).
You can indeed,(kinda-sorta)feel the difference between an A and a B alloy by using same file with same effort et c.In actuality it's illusory.

What file test Does work for is only softer/harder than file itself.That's it(but it's something;albeit useful only on as-quenched alloy,nothing else is usually harder than a file).
Testing is done not with file teeth,but by attempt to scratch as deep a groove as you can,with a Virgin corner of a Known file.

By no means i want to claim some ultimate truth in these matters and you must forgive my sometimes hectoring,categorical tone.English as a Second Language is my usual excuse:).
 
Wouldn't that really only be applicable when heated above the critical temp? What temp would ruin the tempering or soften it? How slow on cooling to anneal it? I guess I should look up some heat treat protocols for HSS

P.S.
I do believe most alloys that we refer to as "HSS" are air-hardening;that would be consistent with it not loosing much hardness when heated to whatever you had it up to.
 
I guess I should look up some heat treat protocols for HSS

Oh yes,Absolutely.
Especially annealing;many don't realize that annealing is a very certain,Exact thermal cycling process,each alloy not only anneals at proper regime(heated to X/cooled at the rate of Y degrees per Z minutes),but also that there are more than one annealed States(like spheroidizing anneal,and others).
On the other hand an anneal is important mostly to machinists,and for finer operations only.
As-forged,with most common alloys is plenty good enough to grind et c.,Normalizing prior to HT is crucially important though.
 
What temp would ruin the tempering or soften it?

With plain-carbon(10xx series)and other "simpler" alloys the loss of existing HT begins at close to 300F
(look up Oxidation colors,they start at Light Straw and go on from there forget my temps in degrees).But that is only as seen on Shined-up steel,otherwise you may miss it.
Cold enough to hold your bare hand on is safe,too hot to touch is beginning of danger zone.
 
You can get a set of files tempered to different hardnesses to test metals . I worked at a place that heat treated drive train parts. We had files tempered to 58 Rockwell for quick on the spot test. If it cut the metal it wasn't properly hard. . At the moment I can only go by how quickly a file removes metal compared to other axes I have . The Gerber/Fiskars hatchets are easily the softest of my cutting tools , then Estwing . I have 3 and have and have sharpened a couple more of the harbor freight hatchets all have been noticeably harder than the fiskars and estwing hatchets. They are close to the council tool boys axe I have. The vintage axes I have and Vaughan hatchets are noticeably harder yet . With the Vaughan stuff being probably the hardest. I know American made Vaughan hatchets are made from 1085 steel
 
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