Blade Point Cracked Forging

Scott Hartman · Nov 13, 2005

I tried forging today. I'm new to knife making and very new to forging. I found a spring and cut the 4inch straight piece off the coil. Heated in the forge and hammered it into a rectangular billet. Hammered a point evenlly from both sides, so as not to form "fish lips". Started hammering the edge of the blade,and the beginner clip point or skinner started taking shape. That's when I noticed the crack coming from the tip back into the blade. Any ideas how it happened and how to avoid it? Thanks for any help, Scott

bartblade · Nov 13, 2005

not for sure but i think it might have been cooled to long while working it. also i think you might need to anle it after working it a few times. it could be from getting work hardened. maybee some forgers will pop in and tell ya the facts

ysforge · Nov 13, 2005

Probably cold shuts, if you noticed that the steel on the end of the bar was forming a "cup" (concave end) so to speak on the end of the bar you where working it too cold. otherwise it could just be stress cracks from the steel showing up early (if so, better now than later)

To avoid it, be sure to reheat frequently, I spend more time waiting on steel to heat than anything else in the forging process. (although I'll usually have at least one more "iron" in the fire at the same time to avoid down time.)

If it's stress fractures showing up, the only thing to do is get newer steel.

Hope that helps!
Tony

Fred.Rowe · Nov 13, 2005

You will want to work all four sides when you are forming a tip. The trick is to narrow and draw it out at the same time. This is where you will see, distal taper, begin to take shape. As the tip starts to thin down in this process, it is
easy to over heat this part of the blade as it is a thinner cross section and heats faster. This is a good time to take on the practice of quenching the tip so as to even out the heat as you do your forging. It is hard to say, without being there , what happened to the blade that cracked., but if you follow this
and the imput from YSforge, you will have better success in this area. Fred

son_of_bluegrass · Nov 14, 2005

Scott Hartman said:
I tried forging today. I'm new to knife making and very new to forging. I found a spring and cut the 4inch straight piece off the coil. Heated in the forge and hammered it into a rectangular billet. Hammered a point evenlly from both sides, so as not to form "fish lips". Started hammering the edge of the blade,and the beginner clip point or skinner started taking shape. That's when I noticed the crack coming from the tip back into the blade. Any ideas how it happened and how to avoid it? Thanks for any help, Scott

What kind of spring? If it was a used auto coil spring it may have stesses from its previous life (might be true of any used spring). I hear tell this is common near the ends but can't say from experience. Other things which can cause cracking include forging too cold, forging too hot, using coal as a fire source and not letting the sulphur all burn off and getting sulphur in the steel.

when asking questions remember the more details the better. If you include something irrelevant it will likely be ignored but if you leave something important out you could get wrong answers.

Scott Hartman · Nov 14, 2005

Thanks for the input. I may have been forging the steel too cold. I'll try fewer hammer strikes per heating. Tony, I did notice some "cupping" and compensating for that error may have caused my crack. I'm using a gas forge,so there's no sulfur issue. The springs were found on a job site,no telling what they're off of, free learning material. I'll just keep trying and enjoying the heat.

Scott Hartman · Nov 19, 2005

I reworked my cracked blade and thought I'd post a photo because it's my first forged blade.

fitzo · Nov 19, 2005

Scott, I *think* that, unfortunately, one must have a paid membership at a certain level to post fotos direct. If you have an online image host like VillageFotos (limited, but free) or FotoAlbum you can create a link to the photo and post that. The trick with the free hosting services is that the fotos go into the public domain.

Edited to add: welcome to the ranks of the paid members! Now you can attach direct.

Scott Hartman · Dec 6, 2005

Thanks to Fitzo! I appreciate the help with getting the pictures in BF, it just took me a while

fitzo · Dec 6, 2005

Success, Scott! You're most welcome. It won't be near as much a PITA for you next time!

Very nice first-forged effort! Looks like it will be a real nice daily carry. :thumbup: