Problem with my temper...next step?

[Shako]

Hello everyone,

Okay, I'll make a full confession right off the bat and get it out of the way.

I'm VERY new to blacksmithing, haven't actually finished my first set of tongs yet (because it turns out I'll have to adapt my forge to allow more room for them), and I've been happily banging away at a knife...in spite of the very clear (and without doubt very reasonable) warning that making knives is a TERRIBLE place to start forging. (waves at Frosty and ThomasPowers).

I've read many times that you like pictures, so I'll explain my problem with a run-down of where I'm at...

1) Old (non-identified) file wanted to become a knife....I start carressing it to shape with my hammer. (photo)

2) I get it to pretty much where I want it (edge about 1.3 mm thick, hardly any grinding to do except to tidy up the contour or the point) (photos )

3) I took it back to the forge to thin out the profile of the knife, taper the tang slightly, and get the edge tidy. I quench it (in oil) and start to temper it directly on the coals (as in the Knifemaking Unplugged dvd) (photos ) BUT run out of light, and figure I can finish the last part (getting more of the blade to a bluish colour) the next day.

4) Tonight I realised that it might be difficult to control the heat from a bed of coals to precisely the area I wanted heating, so thought Icould do it with a gas burner (I can feel some of you raising your eyebrows).

5) I heated the back of the blade, and the part I heated went bronze...and bluish colour seeped down almost to the blade edge. This was exactly the opposite to what I expected. Now the photos (called) show that most of the blade is bluish, but wiht some large Bronze areas near the point and at the black of the blade. (hard to see them because the phots were taking after dark with electric lights on)

I imagine that I can just normalise a few times, then requench and start the heat-treatment again...but I also feel that the edge of the blade is narrower now than when I quenched (maybe 1 mm). Is that possible/normal? 

Remember this is the very first thing I've ever worked on, and although I don't like the idea of risking a new quech if the edge is finer, I don't really want to carry this knife forever worried that if I drop it it breaks. It's ONLY a 10c file from a flea market, but I've spent a fair bit on time on it, and I REALLY LIKE this knife already

 

I'm not sure 'how bad' the situation is....

Does anyone have any ideas or thoughts for me?

 

OOPS sorry, I've just edited this because the first photo should be with the last ones...that's how it is right now.

Edited August 27, 2015 by Shako
forgot something important ;)

[ThomasPowers]

Remember when heating a blade the fat part heats slower than the thin part unless you take special precautions---look up tempering tongs for instance.  I've tempered a lot of blades using my gas stove burners.  (usually do a snap temper in the oven and then a differential temper using the burner)  and at last I TOLD YOU SO!  (also look up stress concentrators wrt blades)

Edited August 27, 2015 by ThomasPowers

[Frosty]

Welcome aboard Shako, glad to have you. DRATS I can't find a "waving snowman" emoticon . Just take my word for it. Frosty waves back.

Didn't you shine the blade up before trying to temper it? If so you got it to black heat so normalize and start over. Then again it might be the way you took the pics. Do NOT aim a flash attached camera straight at a flat reflective surface or the reflected flash will wash out colors and details. Just tape a single ply of tissue over the flash as a diffuser. OR shoot on an overcast day. A tan or light green background works nicely to show detail.

It's good to see you're consistent, not only taking on an advanced skill as a first try but you're even trying an advanced bladesmithing technique. Next time harden it, shine it up a little and put it in a toaster oven and not worry about a differential temper. It's not likely to be a great blade regardless, why multiply the probability of failure?

Frosty The Lucky.

 

[Shako]

Thanks for getting back to me.

@Frosty, yes I did shine it up and could see the first spread of colours really well. the trouble is it left the whole of the blade a straw colour, then I messed it up trying to draw more from the back of the blade. Well...it was RELATIVELY shiny, I figure I'm going to leave in the texture of the original file...the kids think they look like 'dragon scales' (can't get much better than THAT! . I'm not sure how to clean it up besides brillo pad and detergent, or sand paper or a wire brush...? (did I see someone mention vinegar somewhere here?).

Thanks for the tips, very frustrating to SEE the colours but not be able to capture them with a camera.

To be honest, I avoided the toaster oven out of sheer curiousity (that's one of the ways I learn  ), and actually seeing the colours move across the steel was really awesome (I use the word in the old sense). I did (half!) what you said, went back, normalized it, requenched...and ouch, it came out warped (cocking up really badly is the other main way I learn  ), I heated it up, straightened it out, normalized again, and quenched...looked fine. THEN...

@ThomasPowers  then I tempered it using two red-hot hammer heads that I wanted to anneal (one to make a light, rounded hammer to fill in for a ball-pein hammer since I don't have one  ). I figured this way I kill two birds with one knife! I laid one head on the anvil, and held the back part of the knife on it, and laid the second one on top. Worked out pretty well...yah! (although I was shocked at how fast those colours raced across the blade...Lucky I was horribly worried and was watching closely..lol!)

 

So thank you Gentlemen, problem overcome...

Does this relatively quick tempering remove the need for oven tempering? Or should I think of doing that anyway?

 

Yes, as I said, I know I'm going about things a little bit backward, but to counter-balance that, I'm enjoying every moment!

 

AND...I discovered the name for my knife...I'm going to christen her 'Mule'! 

Again thanks...

[jmccustomknives]

Well, the first thing.  Never forge a file with teeth.  They get pushed into the steel, deeper than you'd imagine.  That can cause stress risers that will crack and weaken the blade.  I'll tend to grind most of them away and all at the edge bevel.  If you look down the edge you can see the teeth pushed in.

As far as your tempering method, it's too hard to control the heat.  I'll use a torch for that, but even then it takes practice. 

For your last question, the more complex the alloy the more important to give it a proper temper cycle.  While a simple carbon steel can be done that way, do you know that's what the file is made of?  Did you check it with a sharp file after quenching to make sure it hardened? 

Over all the profile looks good, I'm impressed you didn't over heat the file which is common for a newb using a coal forge.

[Frosty]

And with expert advice from a bladesmith guy I'll quietly move back to the corner and listen. Oh okay, one last thing. What's French for "Mule?"

Frosty The Lucky.

[Shako]

@jmccustomknives...I've already been to your site a few times...that certainly does lend a lot of weight to your words.  I have no idea what the file was made of. An old-looking file, with rather deep teeth..so I guess that's about the worst case to leave them on rather than grind them off to start with. Although the file was about 1cm deep.  'Stress risers that can crack or weaken the blade'...I don't suppose you're just talking about during the forging/quenching/tempering process? (crosses fingers). 

Yes, I tested the edge with a file and it was good.

I had read that over-heating can cause problems, and read in The complete bladesmith' about gently working the edge when it was only dull red, and figured that making mistakes SLOWLY is always the safest way to make them  . Having a reasonably dinky forge probably also helped!

@Frosty... I've read dozens and dozens of your posts  (along with the gentleman above ^^ and many others) in various places on this site, they've already helped me and inspired me to actually get moving into smithing....seems to me that if you go sit in a corner, it's probably to have some peace and quiet..

And you joke about me being consistent...LOL if I start being worried about not messing up at this early stage, smithing will seem look like a very steep hill ahead of me indeed. I was just following an idea, and didn't feel like compromising by being sensible  ( to be honest, I think that being stubborn, or at least tenacious is one of those qualities that are quite useful in this game...along with being PATIENT).. To reassure you, I'm AM going to try to make a proper pair of tongs before I look at making a damascus katana from a piece of steel cable or something like that! 

'Mule' is 'Ane' in French (pronounced EXACTLY like the name Anne...so easy to sneak in if you speak English.

 .

[Shako]

checking...AH...maybe it was Adblock that stopped me posting here..hmmm

Edited August 29, 2015 by Shako

[Quarry Dog]

Did you get the "Forbidden" error?  it's the software that runs the site.  It has been rather buggy/glitchy/kludgy lately, and that particular bug has caused many problems and probably caused a few people to leave.

[Shako]

Yes indeed...but I found the thread where people were talking about it, so wasn't worried. Makes me a real blacksmith then I guess! ;) They should start selling 'I got the 403 Forbidden error message on IForgeIron' teeshirts! ;)