Knife making - help needed.. :(

[Samon]

Howdy chaps, I've kind of hit a wall in my latest creation.. basically I'm making a knife from an old 2.5mm machete blade that was previously modified and I cannot drill or cut it.

My dremel died a few weeks back so I can't cut out the blade shape like I would normally do and after getting some cobalt drill bits to drill new holes in the handle I still can't get through it! I'm guessing that the reason is because the steel has so much carbon content that even my new bits can barely cut .5mm in 20 minutes. I thought about using a hacksaw to cut it out but I can't afford to buy new blades for them just to tickle the steel. I had plans to hand file/finish the shape and cutting edge and I'm confident I can do that but the initial cutting and drilling is currently beyond my small collection of tools.

I would use an angle grinder to cut it out but it will destroy the temper and again I cannot afford to send a small diy project for heat treating..

So, can anyone offer any advice?

thanks in advance guys.

 

[Dave Budd]

machetes are rarely hard, so you must've got unlucky/lucky (matter of perspective!). Normally you can file them easily. It could be that the rusted surface is just a hard skin, so a bit of arub on a grinder to bare metal will sort it out

If you have a bench grinder or belt sander, then I would suggest that you clean the surface of the blade to bare metal with some sandpaper (so you can see when the temper is damaged by grinding). Then cut the shape out a few mm over sized with your angle grinder (using a thin cutting disc) and carefully grind through the coloured portionson your bench/belt grinder, cooloing frenquently.

As for the holes, if you can't drill with cobalt then it likely that you are using too high a speed on your drill. Slow speed and high pressure for steel Try heating the area of the tang to be drilled with a torch until it turns grey (fully tempered) or better a very dull red (low temp aneal). then try again. If that doesn't work, then use your angle grinder to carve slots rather than round holes, the epoxy will fill it and you would never know from the outside.

 

[spandit]

To drill holes, try changing the sharpening angle of your bits - need to be flatter for hard steels. If desperate you can use masonry bits to start the holes

 

[mikew]

You've already had some excellent advice. I would just add that when heating a tang to soften it, hold the blade under water to keep it cool. If you hold the ricasso area then you know the heat hasn't traveled to the blade and messed up the temper. If your hand starts to get hot, lower the blade further into the bucket.

If you get it to a dull red and let it cool naturaly you should be able to drill it with just a HSS bit.

 

[Samon]

the machet is clean,no rust or anything. I tried putting alot of pressure and weight into the drill and doing bursts but it barely got through 1mm of steel..

I don't have a blow torch.. but I could use my stove and bucket of water I guess. I have a few files and the blade really isn't that hard, it's a tramonitna machete that holds a good edge but flexes and bends just like it should.. strange thing it is.

I do have a bench grinder too, so I think I'll cut high up with my thinnest angle grinder disc and slowly take the rest off with my hand tools and clean it up on the grinder.

The handle already has holes but they aren't in a decent place due to the original design of the semi tang thing.. (full tang but fitting in the handle like a hotdog in its bun..) so they are too close to edge of the handle. I'd like to add my own handle pins though, just so I had a go at doing it all.

I will take a picture tomorrow if anyone thinks this will help.

 

[Niels]

Ask Chuck Norris to pee a hole in it

 

[Tony_c]

I once had to dill out a snapped stud extractor which was a nightmare. Cobalt drill bits were very very slow going just like you say. In the end it was a tungsten carbide drill bit (the kind you get for drilling ceramic tile) that worked the best and drilled it out. So I would recommend trying one of these if youve already got a small dent to start on and use a slow speed as the guys have said

 

[Samon]

I once had to dill out a snapped stud extractor which was a nightmare. Cobalt drill bits were very very slow going just like you say. In the end it was a tungsten carbide drill bit (the kind you get for drilling ceramic tile) that worked the best and drilled it out. So I would recommend trying one of these if youve already got a small dent to start on and use a slow speed as the guys have said

They are next on my list.. as my cheap cobalty bits both snapped last night lol! I finally got through the one hole though, albeit at the costof 3 bits and one stone dremel bit (used in ym drill)!

I even held it on the hob flame untill it wouldn't get any hotter and let it cool slowly..

I also cut the whole knife out with my angle grinder, using a thin disc and a 120 grit flap disc to clean up the snaggy bits, and it looks perfect. all I need to do now is cut some slits int he handle with some dremel bits in the drill.. to make room for aluminium pins and hand file the grind.

oh I also broke my damn vice!

 

[Dave Budd]

all in all it sounds like you should've just started with a plain bit of good steel or a premade blade

 

[ForgeCorvus]

This project is becoming a Trial By Ordeal

Post pics when you've beaten it into submission

 

[Samon]

all in all it sounds like you should've just started with a plain bit of good steel or a premade blade

lol, don't say that!

I've had this machete all 'warriored' up and next to my bed for too long and it was just silly! so I had to make use of it in an un lame way, that might actually get used beneficially. I'll go snap a shot of it now it's cut out. I think I will reduce the tip to by a few mm to add strength and keep it true to it's original design. It's kind of like a bowie/trade knife and I will make a sheath for it when I can afford some leather scraps

BRB gona take a pic.

 

[Everything Mac]

I had this trouble with some steel a while back. Then I used a masonry bit... Went through the steel like butter!

 

[Samon]

I had this trouble with some steel a while back. Then I used a masonry bit... Went through the steel like butter!

I actually really glad I'm not the only one who had trouble with random steel! felt like a right noob..

so here it is, the black mark on the tip is steel I intend on removing, the middle mark is where I will start the grind and the end mark is when the scales are gona go to. the scales will be made from the plumb section in the background, cut by my own hand

Of course if any pro would like to charitabley perform the edge grind I'd happily oblige and cover postage!

 

[Samon]

what sort of grind would work best with this? I was thinking a type of convex scandi that goes about 1.5-2cm up the blade and narrowing to the tip. I was considering a false back edge on the clip but I don't want to balls that up..

any advice?

 

[galavanter]

I tried a lot of differant bits on really hard industrial saw blades and the only luck I had was with spear shaped tile drills they did not last for more than three or four holes though just be careful using them though good luck

 

[Samon]

Next time I'll try the masonry bits as I don't have any others other than wood bits.

The knife is now ready for the handle to be sanded down to shape and for it's final blade polish. I'll probably only go up to 600 grit, then force a very deep patina to protect it and cover upand blemishes in the steel.

I went with a full convex grind, used one of my flap discs on the ol' angle grinder and it came out really well. I've cleaned up loads of blades with it before but never a full grind job, so I was suprised when it was as clean as it is!

thanks for the advicedudes