Frustrated: how do you deel with curved/bent bar stock?

BryFry

BryFry

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I tried a search but came up with nothing on this.

I'm new to making knives, but ordered a couple lengths of 1084 from Aldo Bruno. One is 3/16" x 1.5", and the other is 1/8" x 1.5".

I profiled 2 small knives from the 3/16 without "too" much trouble, but my third blade is from the 1/8" and is driving me crazy with all the problems I've encountered.

At first I couldn't figure out why I was having more trouble than before getting the grinds to match from one side to the other, and why I got strange results when I put the whole knife lengthwise against the flat of my grinder in an attempt to smooth out the rough surface of the unground handle.

Well when I grabbed the length of bar stock that it had come from, I realized that the whole thing was curved or bowed pretty noticeably. (being new to this I hadn't thought to check before I started) I then messed with the remaining length of steel to see if I could straighten it back out, but I think I only managed to make it a bit wavy now! :o

Any tips as to what I can do about it? ...And do you think I should mention it to Aldo or not?
 
I had the same problem when I got mine. it seems that it is to be expected with 4 foot of steel that is 1/8th of an inch thick. I haven't noticed any really bad curves in any of the knives I have done, and so i really don't know what to tell you. Aldo should pipe up sometime, he hangs around the forum from time to time.
 
What I usually do is get a good C clamp and clamp it down on a 2x4. The trick is having the back and front of your stock shimmed up with small blocks of wood so the stock can counterbend.
Steel doesnt come perfectly straight unless you pay for precision ground stock.
If its twisted, put it in a good solid vise and clamp just the end. At the other end put a adjustable wrench on it and twist till its straight.
Works for me.
CW
 
Q) Frustrated: how do you deal with curved/bent bar stock?
A) Straighten it.

lol now you know to check that before starting... just straighten it using the above method and your good to go :)

Jason
 
blindhogg said:
What I usually do is get a good C clamp and clamp it down on a 2x4. The trick is having the back and front of your stock shimmed up with small blocks of wood so the stock can counterbend.
Steel doesnt come perfectly straight unless you pay for precision ground stock.
If its twisted, put it in a good solid vise and clamp just the end. At the other end put a adjustable wrench on it and twist till its straight.
Works for me.
CW
Click to expand...

So you just keep tweeking it and checking it until you're satisfied that it's good enough?
 
JasonSCarter said:
Q) Frustrated: how do you deal with curved/bent bar stock?
A) Straighten it.

lol now you know to check that before starting... just straighten it using the above method and your good to go :)

Jason
Click to expand...

haha.... yeah I figured that much . :) Wasn't having much luck with the straightening part though. I only managed to make the thing wavy instead of having one gradual curve.

The frustration came more from a series of things with this particular knife i.e.: curved steel, warped sanding belts, dropped the dang knife onto the concrete floor.... and I can't figure why it's taking this knife sooo long to grind.... mentioned that here:

http://www.bladeforums.com/forums/showthread.php/889269-How-long-does-it-take-to-make-a-knife
 
Or you could design curvy blades... you know... for cutting around corners and such.
 
tryppyr said:
Or you could design curvy blades... you know... for cutting around corners and such.
Click to expand...

ooooh... good idea! ...Maybe I could design a new tactical blade that stabs enemies from around corners! Good thinkin!
 
BryFry said:
ooooh... good idea! ...Maybe I could design a new tactical blade that stabs enemies from around corners! Good thinkin!
Click to expand...

The depressing thing is, if you made one, I'll bet you could sell it (just be sure to add a serrated edge, a saw back, lots of uncomfortable edges, corners, and facets to the handle, and coat the blade with something black).
 
zerogee said:
The depressing thing is, if you made one, I'll bet you could sell it (just be sure to add a serrated edge, a saw back, lots of uncomfortable edges, corners, and facets to the handle, and coat the blade with something black).
Click to expand...

Yeah, needs a catchy name and slogan like: Make holes in your enemies from around the corner using the "CORN-HOLER 3000" ...now with new and improved speed holes for high speed operators!



haha... anyway, kind of on the subject, has anyone ever accidentally bent their knife by clamping it down and filing on it with too much force?
 
Any material and I said any that you get needs to be checked out before put in use. The curved bar stock thing is very common. You start off by getting your piece to be used to be flat on each side and the sides parallel to each other for length and height. Many makers get a surface grinder to help with this. It is just another thing about the knife making you are learning about. If you want steel that is already set to go then buy precision ground stock. This most often comes in certain sizes only. I believe Aldo will do this but of course at a far larger cost. Regards. Frank
 
Frank Niro said:
Any material and I said any that you get needs to be checked out before put in use. The curved bar stock thing is very common. You start off by getting your piece to be used to be flat on each side and the sides parallel to each other for length and height. Many makers get a surface grinder to help with this. It is just another thing about the knife making you are learning about. If you want steel that is already set to go then buy precision ground stock. This most often comes in certain sizes only. I believe Aldo will do this but of course at a far larger cost. Regards. Frank
Click to expand...

Good to know. Thanks!
 
I've never bent one while filing, but I have bent one on the grinder by not being careful. I've learned to be a lot more careful to be applying pressure directly against the section being ground (or evenly from the sides, but that's tougher to keep even as you move). If all the pressure comes from off to one side you wind up bending the knife slowly during the grind. Heat of grinding, pressure out from the side with a fair bit of leverage, thin stock... next thing you know it's curved stock if you're not doing both sides evenly and alternating every few strokes

If the bend is very minor you can often just grind it right out during the course of making the knife. A little distal taper....
 
I have bent one filing but it has a significant distal taper (accidental ;)) and so I am not beating myself up too much. I learned what NOT to do, and that is to not whale on it too hard with a file.
 
thegeek574 said:
I have bent one filing but it has a significant distal taper (accidental ;)) and so I am not beating myself up too much. I learned what NOT to do, and that is to not whale on it too hard with a file.
Click to expand...

That's what I was afraid I might do! ...I'm taking a break from my first time using the file to clean up a small knife, and I THINK it's working alright. Won't know for sure until I sand it down with some paper to check for imperfections.
I'm hoping a couple small file gouges near the tip will sand out....?!?
 
If you are straightening with a hammer, try a rubber mallet, rawhide, or wooden hammer instead of steel.

It has a better chance of a gentle bend correction.
 
So, I just happened to be in the neighborhood. Brian, I AM NOT AN OGRE! Just give me a call and I'll send you out another piece. Guys' I'm on your side. The Carbon steel we have is annealed about as soft as it can be. Single pieces of 1/8" could bend from the tube being dropped on it's end.

The good part is that it grinds a lot easier then any hot rolled offerings. As for as correcting bends in bowed pieces we usually roll them over a set of rollers we have here in the shop. Many times when we cut sheets on the saw the stress in some steel cause it to bow. We've lost band saw blades because of it.
 
Aldo Bruno said:
The Carbon steel we have is annealed about as soft as it can be. Single pieces of 1/8" could bend from the tube being dropped on it's end.
Click to expand...

Damn straight(no pun intended) it's soft. I straighten my 1/4x1.5 1084FG by HAND.... and I'm not kidding. If not by hand, by foot.

Rick
 
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