W's First Attempt, Requesting Help please

S.Grosvenor

S.Grosvenor

Fulltime KnifeMaker
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Jan 24, 2010
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This is where I'm at,

15n20 and W2, 36 layers then flattened.



The examples that I've been using show straight center lines with U or V shaped outer lines, curious as to where I went wrong?:confused:
 
Actually, no, it looks like the center was squashed at a higher "rate" than the outsides, but I suppose it could be something to do with uniformity in heating. How flat was the billet when you put it in the roller?
 
Not rolling, sorry, I'm using a 25ton forging press.

I'd say pretty damn flat, but I'm also attempting with flat dies, should I be forging on a bias?
 
FYI the "Actually, no" referred to me editing my post, I realized my first suspicion was probably false.

I think you might need to preheat your dies, or somehow press faster, it looks like the parts in contact with the dies and the air cooled faster and froze up, while the still hot center squished.

Maybe you just didn't get to press fast enough?
 
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Okay??
I just pivot at the waist to go from forge to press, but I don't preheat dies (yet).
I am going to cut, clean, and stack, then forge it on the bias after the weld is set to see if I can get some U's going.
 
You need to make sure and forge the original stack (layers running horizontal to the dies), down more before you start forging down the sides (layers running vertical), and once you do avoid forging as much on the other sides as possible, except to even up the sides.

There are also some tricks to get more activity, but the most important part is set your weld (layers running horizontal to the dies) draw the billet out depending on billet sides, I like to get my billet down to about 1/2-3/4" thick, ~2" wide, nice and even, and then turn it up on it side (layers running vertical) and then forge back down to where I'm going to restack. It's the upsetting process (when you take a wide bar turn it on it's side and then forge down) that gives you the distortion you need. You just need to keep from letting the bar get too thin when you turn it on it's side, that it buckles.
 
I don't think you need to preheat your dies. I've never done such, and don't know anybody that does personally (or atleast, they're doing it in secret if so) Your dies will be smoking hot after the first forging session anyway.

It's a technique issue. You can restack this billet and still get some activity, but yeah, if you're looking for more consistency, I'd try to do something different with this one, and try another stack for this pattern.


Another thing to consider, if that's the *very* end of your bar, it's not going to represent the pattern, if you've done entirely press work. The press moves the inside faster as it cools the outside with constant die contact, and tends to squeeze the guts out the ends of the bars.


I can see from the little of the side of the bar that the pattern changes a little bit further in, so you could have more movement there.
 
Javand, Thanks.

This is cut and stacked (3 = 108)



going to stack again = 216 and see what it looks like, I'm liking it a little better now.
 
javand,

I have heard of pre-heating press dies for damascus, but I'm not aware of how common it actually is. I do have some forging experience and knowledge although I will admit my actual Damascus experience is limited. If you look at some of the pros, they're using air-over-hydraulic or electro-hydraulic presses that are relatively "fast", so the whole pressing operation is done long before the billet has a chance to cool very much on the outside.

If someone was using a hand operated press, the time of contact with the plates would be much longer and the compression process much slower, so it would be giving it all kinds of time to cool and do things like in the first photo shown.
 
FWIW, I knew Steve was using an electro hydraulic press, I doubt you could effectively make W's with a "shop" type hand press.


Not sure who you classify as "pro" but the guy I learned, and work with, owns one of the very few production damascus shops in the world atm. I also work with numerous other makers many of them ABS MS or JS, and none of them that I'm aware of preheat their dies. Not saying nobody does it, just saying I don't know anybody that does.


I do preheat my rollers on the rolling mill, that's to help them grab the billet better, not to avoid cooling the billet, since the rollers don't keep much maintained contact.

After 5 minutes on even the power hammer dies, which aren't in constant contact, you can fry and egg on them.
 
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Looking good Steve, when you cut and restack, make sure to etch the ends of all your bars so you can line up the layers as close as possible. The more pieces in the stack, the more even you can get the layers if they're tacked well, since you'll have more synchronicity where you alternate the flips. Dunno if that makes sense. If you take a bar and cut it into two pieces, and fold it, the place where you cut it, will sync up well, because you're folding the pattern back on itself at the cut, the ends however, are prone to a lot of variance, since you're trying to line up two ends of the bar. The more cuts, the more you're lining up cuts, and the only places that are less prone to sync are where the second piece folds back over the bottom piece, and where the top piece folds back over the next to last piece. Still you're mitigating the distortion because the non-aligned points are from closer sections of the bar.


Layers not lining up are a big pet peve of mine personally, many people don't care though. I've been known to restack a perfectly good billet because of one little misalignment, but usually something cooler ends up as the result.


BTW, here's a pic of what I usually like to see before the first restack for an active W:
IMG_0992%255B1%255D.JPG



And here's what that bar eventually became:
IMG_2977%255B1%255D.JPG
 
javand said:
FWIW, I knew Steve was using an electro hydraulic press, I doubt you could effectively make W's with a "shop" type hand press.


Not sure who you classify as "pro" but the guy I learned, and work with, owns one of the very few production damascus shops in the world atm. I also work with numerous other makers many of them ABS MS or JS, and none of them that I'm aware of preheat their dies. Not saying nobody does it, just saying I don't know anybody that does.


I do preheat my rollers on the rolling mill, that's to help them grab the billet better, not to avoid cooling the billet, since the rollers don't keep much maintained contact.

After 5 minutes on even the power hammer dies, which aren't in constant contact, you can fry and egg on them.
Click to expand...

Sorry, maybe I shouldn't have worded it like that with "pro", I meant it in a looser fashion, more like "done like a pro".

I've seen a few hobbyists using hand pump hydraulic presses (I've forge welded with one, but I haven't made Damascus with one), and the billet stays on the press a lot longer than with an automated press.

I was careful to add the disclaimer in my previous post that I am no expert on this. I do have hot work experience, but very little in knifemaking.
 
Ian, no worries, and I know it's likely lost in the text, but I wasn't trying to call you out or be condescending, just wanted to qualify my previous statements, and give some reference to my qualifications to make them.


Cheers,

Javan
 
I have only made two billets (I cut split them for feathers) but Bruce Bump does a great WIP on feathers, and I think it's in there that it's mentioned that you need to reduce the billet,once flipped, to 20% of what it started. So if you started 2" you should draw it out to 3/8" before restacking. And like it was said earlier, don't forge the sides after you flip.
 
forged out the blade and it is pretty close to what I was going for, trying to match it to the wood somewhat.

 
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