First Greenpete Knife

[Pandabean]

Hey all,

Been a while since i have been on the forum.

My mate managed to stumble across Greenpete's site about how to make a knife. My mate had everything apart from a forge. So we found an old cast iron barbicue and bought an extractor centrifugal fan and some pipe. We eventually got the forge going (it even managed to get so hot that it slightly melted part of the steel file. Our blades are smaller than Greenpete's as it was a test to see if we could do it. So far we have managed to get nice blades out of it but they still have a slight pattern to them that cant be grinded out.

I will post pics soon.

However my question is what should the blade angle be? We did the filing of the edge by hand without the jig and my one has been measured to be about 40 degree angle and the bevel isnt too wide. Will this do or does the blade have to be filed down further to a lesser angle?

Thanks,
Andy

 

[Draven]

Keep in mind that you don't really want to melt the steel . . strictly speaking, an air supply isn't really necessary for annealing the file.

Out of curiosity, what do you mean by a pattern that can't be ground out?

And I'd say that 40 degrees is a bit obtuse for my liking, I'd try and get it closer to 30 but it's really personal preference. Seeing as you said the blades are small, they're unlikely to be used for anything too heavy so I'd definitely try to get the angle a bit more acute.

Looking forward to pics And pics of your forge! I'm trying to put one together myself!

Cheers,
Pete

 

[Pandabean]

Melting a bit of the steel was by accident. This was our first go at a forge so we weren't sure what to expect or wether it would work properly. We had the air supply in order to get the heat up a bit and it did work well.

Regarding the pattern, I might be able to show you in the pics. Just getting my mate to send me some photos tonight. Its left over from the heating of the metal.

I might grind the angle down a bit this coming weekend. I am a bit worried on how to do this as I dont want to over do it. My mate will be bringing up whetstones, a dermel and a couple of files. At my place I dont have the grinding stones etc. Any ideas if the dermel will do a good job?

Regards,
Andy

 

[Draven]

Melting a bit of the steel was by accident. This was our first go at a forge so we weren't sure what to expect or wether it would work properly. We had the air supply in order to get the heat up a bit and it did work well.

Regarding the pattern, I might be able to show you in the pics. Just getting my mate to send me some photos tonight. Its left over from the heating of the metal.

I might grind the angle down a bit this coming weekend. I am a bit worried on how to do this as I dont want to over do it. My mate will be bringing up whetstones, a dermel and a couple of files. At my place I dont have the grinding stones etc. Any ideas if the dermel will do a good job?

Regards,
Andy

Yeah I figured the melting was accidental I apologise though, I've not used a forge at all so I'm hardly one to criticize

That sounds like a hamon (a wavy line along the edge of the blade to the tip) but I didn't think you could get those without clay hardening. I'm really curious about this one I love patterns on blades.

Are the blades heat treated already? If they are, a dremel will probably get it hot enough to ruin the heat treatment, meaning it will need to be done again. It can also give a very uneven edge; I was using a dremel with a sanding drum on a blade that wasn't heat treated, and it tended to "sink into" the blade, leading to lots of pits which had to be ground out. I'd recommend a belt sander or a file so it can be done with more precision. One mistake that I find to be quite easy to make when narrowing the angle is accidentally pressing the file square against the grind, which obviously doesn't change the angle at all, just takes off stock. Watch out for that, and otherwise just take it slow! It helps to use permanent marker on the blade to see where you're removing metal.

Cheers!
Pete

 

[Pandabean]

Here we go. Pictures of the knifes.

Top one is mine, the thiner one. The bottom is my mates. The reason for it being shorter was the file broke and we decided to carry on. I cant show the marks I was talking about as the images arent high enough quality (got them sent to me). But on the bottom knife you can just make out the patches of the dark marks.

 

[Pandabean]

So what do people think of the angle on these blades are they too steep/shallow?

How much will a steep angle affect the cutting of items?

I will try and get the forge pics as soon as possible. After reading someone elses attempt at this they had very little tools only an angle grinder. I might try this on my own as I have said my mate is the one with all the tools.

 

[Draven]

I would say the angle is a bit too obtuse, particularly on the bottom one, since it looks considerably thicker. The larger the angle, the harder it is to cut - simple as that. It will tend to break things apart rather than cleanly slice when doing food prep, and your chances of cutting a really hard wood with a large angle on the cutting edge are slim. If you take a look around the forum you'll see how wide some people have the bevels, even on relatively thin blades. As a general rule, the thicker the blade, the harder it is to slice and if I weren't such a fan of the Scandi, I'd suggest that the bottom one have a full flat bevel, with a slight secondary at the edge, which would make it much more suitable for food prep.

I'm still not entirely sure what you mean about the dark marks but I'll see what I can do.

If you mean the black marks at the bottom of the handle, it just looks like something burnt onto the metal.
If you mean the marks on the bevel itself, it looks like deep scratches left from grinding/filing that are just blacked from the heating. You can get rid of these with coarse paper and progress through the grades, but they'll work out with time and sharpening, too.
Alternatively, if you mean the cloudy black marks on the blade, it just looks like the discolouring of the steel due to heating - this is pretty much unavoidable from my experience. I made a Sgian Dubh with a pretty much totally black blade after quenching..

Hope this helps!
Pete