Making a Bolo machete/ big chopper. Could use some tips.

[Huntsman Knife Co. LLC.]

Hey guys,

I'm looking to make my dream machete/ hybrid chopper that will be ideal for everything from clearing brush to chopping down an oak tree. I am thinking the blade will be around 15 inches and will be about 2.4 inches at the widest, tapering quite a bit towards the handle for alot of forward weight. Thickness wise I am probably going to go on the fat side with .187-.150. The knife will most likely have a high saber grind.

What steel would you recommend for this blade? I want very high toughness and flexibility and will have the blade professionally HT, most likely with a differential temper. Right now Im looking at 5160, 52100, and 1084 and leaning towards 52100 because of its edge holding. All are pretty inexpensive and seem to have excellent properties that would lend to a chopper/machete. Is there a significant difference in grindability between the steels? Also which steel will be the least likely to warp? Are there other steels that would be better suited for the blade in mind?

Also what are some tips for grinding such a big piece of metal? I use a 2/42 craftsman and I also have a 4X36 inch sander than could be used for shaping.

Thanks in advance!

 

[chad2]

I would go with 5160 because in the field it will be easier to resharpen 52100 not so much. And the edge retention on 5160 is fabulous.

 

[Storm Crow]

I have gotten very good results with 5160 with a simple heat treatment.

With a long blade, expect that it will warp. If it doesn't, you can be happy. If it does, you won't be surprised. With 5160, at least, you have about a 30 second window after the quench before it sets up fully during which time you can sometimes carefully flex it back straight. If you wait too long or try to flex it too far, you can snap the blade off.

So if it's not wanting to flex back straight, don't force it. Go ahead and temper it once, then use this handy trick I learned from Rick Marchand. After the first tempering cycle, take a flat piece of steel and lay it along the warp in the blade. Use a couple of big washers as spacers between the blade and the flat steel. Use a C-clamp to flex the blade over toward the flat steel, slightly past straight. Then run it through another tempering cycle, take the clamp off, and check. If it's straight, run the blade through your third tempering cycle and get on with cleanup and handles. If it isn't straight yet, clamp it again and run it through the third cycle. If need be, clamp it a bit tighter and flex it over more this time. If the second try doesn't get it all, you can try another couple times or so.

If it's just really fighting you, I'd start the heat treatment over, normalizing the blade two or three times and straightening, then quench again.

Properly heat treated, 5160 will be very tough and hold an edge quite well while being easy to re-sharpen when the time comes.

 

[elchris123]

Clearly you've done your homework. Those are great steels. Personally I'd go with 5160 or something along the lines of 1055. tough as hell and easy to sharpen.