Introducing gruesome! My first knife

[Stephen Ray]

I did this with an angle grinder switching between a low grit and high grit wheel. I used a cutting wheel to get the rough shape. It is, unfortunately a mild steel but nonetheless it is my first blade. Criticism is not only welcome but encouraged. Thank you.

[Doug Lester]

It has a nice profile.  Try getting the largest bastard mill file that you can find and try to work that primary bevel all the way back up to the spine.  It won't exactly be a flat grind because the file will flex some.  Also,  look up draw filing.  That's the technique you will need to file a bevel into your blade.  After you establish your bevel with the bastard smooth the finish with a second cut and then s smooth cut file.  After that you go to sandpaper on a hard backing to get the finish that you want.

 

Doug

Edited October 10, 2020 by Doug Lester

[Stephen Ray]

26 minutes ago, Doug Lester said:

It has a nice profile.  Try getting the largest bastard mill file that you can find and try to work that primary bevel all the way back up to the spine.  It won't exactly be a flat grind because the file will flex some.  Also,  look up draw filing.  That's the technique you will need to file a bevel into your blade.  After you establish your bevel with the bastard smooth the finish with a second cut and then s smooth cut file.  After that you go to sandpaper on a hard backing to get the finish that you want.

 

Doug

Thank you for the advice. The fiscal vacuum that is my life can probably manage to fit that in the budget next week. Is there a specific grit you recommend? Or just wing it? Like I said. It is a mild steel so right now it's all about practice and refining technique.

[billyO]

16 hours ago, Stephen Ray said:

Thank you for the advice. The fiscal vacuum that is my life can probably manage to fit that in the budget next week. Is there a specific grit you recommend? Or just wing it? Like I said. It is a mild steel so right now it's all about practice and refining technique.

If this is mild steel, I'd probably just concentrate on practicing filing the bevels to learn that.  Hand sanding isn't really difficult to learn, just time consuming and IMO would be a waste of time, paper and effort because that is something you can learn on a real blade.  

A typical knife progression would be something like: 

1) File/grind profile and primary bevels using files/angle grinder (or belt grinder with 36-60 grit);

2) clean up the grinding using smoother files/angle grinder with flap discs (or belt grinder using 120-220-400 grit progression);

3) Heat treat blade (when you use a steel with over .6% carbon);

4) hand sand starting at 220g and progressing through 400-800-1500-3000g depending on what finish you want.

If I were instructing you, I'd say use the tools you have and focus on trying to get the plunge line (red line) even on both sides, getting/keeping the bevels flat and parallel, keeping the edge centered while grinding/filing,  and getting a clean and crisp transition line between the spine and the bevel (blue line).  And because it looks like you already started, I'd also spend time on this mild steel continue your practice the filing on the spine perhaps trying a vine pattern or something, 

There's no real secret to hand sanding, you're just removing the coarser grit scratches.  Not much to practice here, because you're not removing material fast enough to really screw up the blade.  

 

PS - Don't think that the lines have to go where I put them on the picture.  I just did that to clarify what lines I'd focus on using mild steel for practice.

Edited October 11, 2020 by billyO

[Stephen Ray]

Well, it's not as refined as I had hoped it would be. It is heat treated now. The bevels are a bit more defined and I am trying to decide on the scales now. I decided to make the pommel into a bottle opener and the thumb grip thingy has a single seration in the middle of it for cutting rope/cord. 

[Alan Longmire]

2 hours ago, Stephen Ray said:

It is heat treated now.

 

I thought you said it was mild steel?  

[Stephen Ray]

13 hours ago, Alan Longmire said:

 

I thought you said it was mild steel?  

I followed the recommendation to heat treat it anyway just in case my steel was misidentified. It does seem to be harder and the file doesn't bite anywhere near as easily as it did. So in conclusion I would have to say that while it is not a HIGH carbon steel; it definitely seems to have some carbon content. I made an improper assessment based on the sparks thrown off while making the initial cuts. Makes me very appreciative of the trove of resources to be found here. 

[Alan Longmire]

Ah, good old A36 "mild" steel that can be anything.    It oftens hardens a bit when quenched, with the key phrases being "often" and "a bit."  

[Stephen Ray]

That explains why there is still "a bit" of bite with the file. I am going to be remaking this knife with a much better steel. I feel like this should do the trick. 

[billyO]

15 minutes ago, Stephen Ray said:

I feel like this should do the trick. 

That should do the trick.  I'll forewarn you (not to dissuade you, just prepare you), that used springs can have micro-cracks that don't show up until after quenching.  

So if you end up with a cracked blade from this, it might be that you did everything right and the crack was there to begin with.  

But it's just as likely that this is a solid piece of spring steel and will be fine. 

Just want you too be aware of the risk when using salvaged steel. 

[Stephen Ray]

Would quenching a short length of this before I do any work with it be informative enough? And on a side note, would acid flux be acceptable for acid etching? Or would I need something stronger? I vaguely recall hearing that it can be used to highlight hardened vs not hardened steel.

[billyO]

19 minutes ago, Stephen Ray said:

Would quenching a short length of this before I do any work with it be informative enough?

Unfortunately, probably not.  It's possible your short sample is good, but other parts of the spring aren't (or the other way around).   Unless you can actually see cracks after cleaning off the rust, I'd go ahead and forge a blade out of it, do the HT and hope/expect(?) the best.  

What that would tell you, however, is if your chosen quenching medium is fast enough.

I'm not sure the acid etching would tell you anything  as this spring should be a homogenous steel, so there'll be no contrasting colors/shades to see.

Edited October 16, 2020 by billyO

[Alan Longmire]

1 hour ago, Stephen Ray said:

would acid flux be acceptable

 

Nah, that stuff (zinc chloride) just makes it rust.  Strong vinegar or hot lemon juice will do it on a highly polished surface.  If you're thinking of trying to get a hamon on that coil spring, chances are you won't.  It's usually 5160, which is too deep-hardening to get a good hamon.  You can get a sharp line with an edge quench, though.  If the coil is 9160 you might get a better one, it doesn't harden as deep.