Jump to content

Lawn mower machet (WIP)


Recommended Posts

Started working on this today, it's like a giant camp knife, small machete, ( I'm going back out to do more in a minute, had to come get lunch)

all I've done so far is flatten the blade and cut come notches and curl a handle. I'm trying to decide what to do with the blade now, curve some like a kukri? or leave straight? point the tip? or leave a chisil tip?

anyways, here are a some pics.

 

IMG_4319.JPG

 

IMG_4320.JPG

 

never mind. Lets just say, that I am never quenching in water again!! :angry::angry:

Edited by oldanvilyoungmsith
Link to post
Share on other sites

That's all that needs to be said. It was looking good there, pity.

Greg

Link to post
Share on other sites

I gather that you quenched it for some reason, which caused a crack, which then broke when you went back to hammer. Let this be a lesson for us all, "never quench tool steel just to cool it" :lol: .

 

If you need to switch ends, you really need to let it air cool well down into the black. laying it on the anvil and letting the anvil be your heat sink is about as fast as you want it to cool down.

 

I once was trying to put a fancy curl in the end of a tang. With mild steel you can make the fine curls, take a heat, pour a bit of water on the end and us that for leverage to get the rest of the curl. You can do that all day in mild. The first time I tried it in tool steel, the fine little curl I'd just spent 45 minutes drawing out, snapped right off :angry: . Just last year I was working on a sword, for some reason I needed to change ends. I let the end cool to visible black (still too hot)quenched it, and broke the piece right at the quench line.

 

You've learned an important lesson, grasshopper. Now when you can...hey, no fair!

 

Geoff

Link to post
Share on other sites

Damn! Was looking forward to seeing this progress.

Thanks anyway ;)

 

well, Dad has a few more old lawn mower blades and I hope to try again in a few weeks.

 

Before I can try agian I need to get a new hairdryer forge blower, cause mine died on saturday. and I'm also planning on making a new forge before I do another knife.

 

oldanvil.

Link to post
Share on other sites

I gather that you quenched it for some reason, which caused a crack, which then broke when you went back to hammer. Let this be a lesson for us all, "never quench tool steel just to cool it" :lol: .

 

 

Geoff

 

pretty much, I was "done" working on the blade so I decided to harden, heated to red, quenched, and I heard a plink! I have never broken something in a quench before so this was a uhoh moment (you know, you hear the clink and that dread builds in your mind) when I pulled it out, there were 3 big cracks in the blade, and several small ones. I stuck it in my vise and demolished it.

Edited by oldanvilyoungmsith
Link to post
Share on other sites

Ah, yes, the Dreaded "Ping". When in doubt, quench in oil. Veggie oil is good because it has no toxic chemicals like you get with used motor oil. Pre-heat it with a piece of hot mild steel and it will actually cool the blade more quickly, making it harder. When cool, the oil is thicker, more viscous. When it's heated, it will flow around the blade more easily and pull the heat out more quickly.

Link to post
Share on other sites

Ummmmmm, Hmmmmmmmm. I like the way you type.

 

 

I'm glad you posted this project. I'm working on a machete for a guy based on the Woodman's Pal right now. I started with a mower blade, but didn't have enough steel to do what I wanted. Switched over to a piece of leaf spring and things are falling into place. The blade will be short (around 10"), with a D guard and a rubber handle over a hidden tang. I've used rubber in the past for grip scales, but never for a hidden tang. We'll see how it turns out. I'll try to get some pictures up when it's done.

Link to post
Share on other sites

I think the water quench is too severe for whatever the steel is that makes up lawnmower blades. Before you go too much farther, you might take a piece of the first one and oil quench it to see how it reacts.

 

From the look of your pictures I see three things:

 

1) You didn't do any grinding that I can see. That leaves you with a firescale surface (which is uneven) and all of your hammer marks. All of that will make for a very challenging HT. A smoother surface is less likely to create stress risers, which are places where cracks can form.

 

2) I'm betting, from the look of the remaining surface, that you overheated the piece prior to quenching, maybe as much as 500-600 degrees. It's hard even for experienced knifemakers to judge temp by eye.

 

3) You don't talk about normalizing. If you didn't take some normalizing heats, 2 or 3 is usual, that will decrease your chance of getting a successful HT.

 

I can also see that you didn't forge the edges down much ( I can see the bent edge typical of a lawnmower blade ), that is going to leave you with a lot of stock removal to do, more forging = less grinding.

 

It is not usual to go directly from forging to heat treating. In nearly all cases you want to grind the surface clean before HT, even with punches and chisels.

 

Just my .02, I hope that some of that is useful,

 

Geoff

Link to post
Share on other sites

Love the slingblade pic!

 

Sorry about the blade getting destroyed with the water quench. I think most of us have had that happen sooner or later when we tried to use water. Unfortunately, mine was lesson with a long katana blade where I wanted to do a traditional quench in water. The blade curved up about 5 inches and had hairline cracks everywhere. Oil is your friend but it helps to learn these lessons for yourself sometimes. I look forward to seeing your next attempt.

Link to post
Share on other sites

I think the water quench is too severe for whatever the steel is that makes up lawnmower blades. Before you go too much farther, you might take a piece of the first one and oil quench it to see how it reacts.

 

From the look of your pictures I see three things:

 

1) You didn't do any grinding that I can see. That leaves you with a firescale surface (which is uneven) and all of your hammer marks. All of that will make for a very challenging HT. A smoother surface is less likely to create stress risers, which are places where cracks can form.

 

2) I'm betting, from the look of the remaining surface, that you overheated the piece prior to quenching, maybe as much as 500-600 degrees. It's hard even for experienced knifemakers to judge temp by eye.

 

3) You don't talk about normalizing. If you didn't take some normalizing heats, 2 or 3 is usual, that will decrease your chance of getting a successful HT.

 

I can also see that you didn't forge the edges down much ( I can see the bent edge typical of a lawnmower blade ), that is going to leave you with a lot of stock removal to do, more forging = less grinding.

 

It is not usual to go directly from forging to heat treating. In nearly all cases you want to grind the surface clean before HT, even with punches and chisels.

 

Just my .02, I hope that some of that is useful,

 

Geoff

 

in those pics I wasn't done working, that was after straightening the blade and making the handle. I didn't get any other pics. It looked a lot better before I destroyed it.

Link to post
Share on other sites

you can't quench any steel that's been forged in water without normalising. it will break. a lawnmower blade will probably crack in water no matter what you do. most any steel will crack in water if you overheat it. mystery steels should always be tried in oil first.good luck n ext time...

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...