Michael Cochran Posted July 6, 2015 Share Posted July 6, 2015 I have yet to make a double edged blade and thought making a letter opener would be good practice. I started with a piece of 3/16x3/4 'weld steel' from lowes instead of messing up my good steel and it's decent but I need a little help. I'm thinking as i hammered in my bevels that I got a little sloppy because my center line is not centered or straight. One side is much worse than the other but both have a little crookedness. I'm trying to get it straightened back up but it doesn't seem to be moving. I know it's not the fault of my tools, the files im using cant do anything without me telling them to do it. So I have to ask since I cannot seem to figure out myself, how is the best way to fix this. I've tried leaning towards the centerline some but I don't want to move the whole line, just the wrong spots. I'm sure there's an 'easy' answer and I just haven't found it yet. I only have a bench grinder (and prefer not to use it because I'll really mess up what I have) and files at this time. Any help no matter how simple it sounds would be appreciated. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted July 6, 2015 Share Posted July 6, 2015 (edited) Because it is two profiles / planes coming together you cannot treat the spine as an independent object.Where your spine has moved to the left side it is because the right bevel has lost too much metal…it has gone too low and eaten into the left side. The left side has got to be taken to the same height to get the spine back to the centre.For instance... In the top image you posted there appears to be a hollow in the plane of the lower bevel about a third of the way along from the tang to the point. You can see that the hollow has eaten into the upper bevel and the the spine has moved across it. That lower bevel needs to have the metal removed on either side of the hollow area to put it all in one plane and match its lowest level. That will push the spine across to the top bevel all the way along. The top bevel will then need to be taken down all along its length to bring the spine back central.If I am misreading the photo and it is not the lower bevel that is hollow, then it is the top bevel that is full at that point. In that case take more metal off the high point...I am not a knife maker but there is an old saying about 10 minutes at the anvil will save 10 hours of benchwork/filing. When you are forging look for the play of the light and shadows to inform your hammer blows. The hollows can be seen and corrected before you start to file and grind.Good luck.Alan Edited July 7, 2015 by Alan Evans Quote Link to comment Share on other sites More sharing options...
Michael Cochran Posted July 7, 2015 Author Share Posted July 7, 2015 Thanks, Alan, for that help. Both pictures have my centerline movin upward in the picture. When holding it in your hand looking from the tang to the point on both sides of the blade it's on the left hand bevel that the line leans to. Just to clarify, you said level the side opposite the way the spine is pointing and then lower the other side to match?I think I just got in to big of a hurry when I was finishing up rough forging and let the hammer slide too far. I'm not very good at forging blades, I can grind the out and finish them nicely but I'm still learning how to properly forge one. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted July 7, 2015 Share Posted July 7, 2015 I tried to both edit and add a response to my earlier post to make it clearer but the forum software prevented me from posting it…hey ho when the mods get to control the software again maybe they could add this to the original Letter opener thread by M Cochran. I have done a drawing which may help you to understand what is going on. The drawing on the left shows an extreme example of a spine going offset. By alternating a filed "vee" from each side the spine becomes a zig zag. On your blade that is what has happened only obviously more subtly. The sketch on the right shows a cross section through your blade at the lowest point of the hollow I pointed out in my earlier post. And the dotted line shows where the speckled material must be removed. The rest of the bevel which has the hollow in it must also be taken down to the level of the lowest point. As far as I can tell from your photo most of the metal needs to be removed on the tang side of the lower bevel's hollow, that will push the bevel almost straight. On the point side of the hollow the lower bevel must be taken down to the lowest level of the hollow. That will push the spine across to the top bevel all the way along. The top bevel will then need to be taken down all along its length to bring the spine back central. The lowest point of the hollow will determine your blade profile at this stage. Because the lower bevel is hollow you may have a problem to get the spine central without having both bevels concave over their length. The next one will be better!Alan Quote Link to comment Share on other sites More sharing options...
Michael Cochran Posted September 28, 2015 Author Share Posted September 28, 2015 Alan, I'm sorry I didn't see your reply before now for some reason. The sketch really did make things clear for me, thanks. I will be making another attempt one day and will hopefully get it a little closer than this one. I have yet to finish it simply because i dropped it and it disappeared under my forge table and I haven't felt like getting on my hands and knees to climb under there and get it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.