View Full Version : Hammering evenly, why?

09-17-2004, 03:44 PM
I've heard alot of times that you should hammer both sides of the blade evenly, also same thing for grinding, to help prevent warpage. I don't understand how it could possably make a difference though, once you normalize a few times and harden shouldn't any of the hammering effects on the crystal structure, etc be completely erased when the steel goes into solution? As long as the end result is even does it really matter that it took 48 hammer blows on the left side and 85 on the right?

I've never paid much attention to hammering evenly, I just hammer where it needs it, and due to my newb skills it's not likely to end up even at all. I've had relativly few problems with quenching though which I assume is due to normalizing and having a fairly even surface when doing the HT. Have I just gotten unusually lucky, or is hammering/grinding both sides evenly another one of those myths?

09-17-2004, 05:03 PM
Any difference from one side to another invites warping .So you should always try to use the best practices. Normalizing certainly helps but maybe you've had some luck so far !

Ed Caffrey
09-17-2004, 10:27 PM
I don't believe it's a myth. As Bladesmiths we have far too many factors working against us in regards to keeping blades straight and true that I think every advantage we can give ourselves to make things eaiser should be taken. Uneven forging can lead to warpage int that there is a larger mass of material on one side that the other, likewise with grinding. Larger or smaller masses of material will either heat more slowly or more rapidly than the surrounding material, which means that particular spot will more more or less that the rest of the blade, resulting in warpage. Normalizing will help eliminate most warping, but if you get careless, no amount of normalizing in the world with save you. Attempting to limit the factors that can cause failures will lead to better habits in your methodology. A good bladesmith is not one who does not make mistakes......a good Bladesmtih is someone who can minimize mistakes, and when they do occur, understand how to fix them.

Robert Washburn
09-18-2004, 04:05 AM
Very well said ED Thanks Robert

09-18-2004, 08:42 AM
Way back when I was still learning, (still am) I did not know much about normalizing and was using a flattener as the last forging step. I reasoned that the anvil was flat and the flattener was flat I would only need to do one side. So I forged 5 or 6 blades and only did one side and when heat treated guess what! every one warped. Like Ed said we need to use every trick we can. Gib

09-18-2004, 02:57 PM
Thanks, I think I might have explained my question slightly wrong though... What I want to know isn't if an uneven blade will warp with proper HT. What I want to know is if the blade is perfectly even, but it took uneven effort to get there, then would it matter?

Example, I use a 5# hammer on the left side and hit it 50 times, and I use a 2.5# hammer on the right side 100 times, when I'm done the blade looks perfect (ok, perfect is an exageration, but pretend I can do perfect for the sake of this example), will that perfectly shaped symetrical blade remember that I didn't use the exact same process on each side or is it only the final result that matters?

09-18-2004, 05:22 PM
I think thats what previous posters would call hammering evenly on each side.


09-18-2004, 05:50 PM
Oh, have I just misunderstood the idea of "hammering evenly"? If that's what it is then that would explain everything, heh.

paul harm
09-19-2004, 10:00 PM
in i believe the last issuse of blade magazine [ either ed fowler or wayne goddard ] was telling a story about an old blacksmith who would hit only one time before turning the steal over to hit the other side . the reason for the story was that he was at one time having trouble with blades warping. after paying closer attention to how many times he hit a side before turning it , and hitting both sides the same , no more problems with warping . in my opnion , use the same size hammer for both sides trying to hit both sides the same amount of times and turn often . i like to start on the oppisite side on the next heat - you'll move more metal when it's hot [ the first 5 blows , than the second 5 when it's cooler ] . just me , others will have different ways to do it . same with grinding - grind a little , turn it over and grind a little more . paul