It's been a long long journey to finally get my first blade finished. From my paint can forge that couldn't get hot enough for heat treating to only learning about mild steel and why you can't make a knife with it only after I had built a second fire brick style forge and tried to repeatedly quench it to no avail. It's been a journey to say the least. And I have loved every second of it. This is kind of a test piece to get a feel for everything. It's O1 tool steel. 5 and a 1/4 inches long with a 2 inch blade. I have one exactly like it in 1084 that hardened and tempered but I have not started finishing it yet. I was just playing with the two steels that I felt I could handle heat treating myself. I have done handle work in the past so this was strictly to get a feel for blade making. I made a file jig to do the bevels and also tried to work them a bit with the diy belt grinder I posted in the grinder section of the site. I added a flat platen to it but due to the slight wobble in the 1x42 belt I felt like I was doing more harm then good with the grinder. I learned a lot (mostly what not to do next time) that will help with my future projects. The only thing I really ended up not being happy with was the final sharpening of the knife. I ended up with one side of the blade nice and flat but the other ended up very noticeably convexed from me not being able to hold the angle consistent on the diamond stone. I reluctantly evened it out with a lansky sharpening system. It worked well but just as the lansky started to bring it to an exact point at the edge I stared loosing chips off the edge. I was going at a 20 degree angle on both sides and have used the lansky to resharpen many knifes without this ever happening. I am scared to ask but is this something to do with my heat treat that I did wrong? Cant call it a knife without a handle attached so without further ado here she is. My first blade.
Wicked job! I know how it is getting over the hurdle of that 'first' finished blade! I've only completed 3 to date and I am chomping at the bit to make more, but sadly working out of my now FULL single car garage means I probably won't get anything done until spring! My main worry is losing the 'feel' For it Great job Steve, looking forward to seeing more from you! Griff.
Well done for your first blade. Even more so because of the somewhat winding road you took to get there, learning some important lessons along the way. At the end, you've got something to be proud of. BTW, if the lansky is chipping the edge, you may have the blade a bit too hard. You could try doing a brass rod test. If you notice more chipping or cracking on the edge, you can run it through another tempering cycle to bring down the hardness a bit.
If sharpening on the lansky is chipping the edge the knife is probably overly hard, which luckily is an easy fix without handle scales. You didn't mention tempering temp or time after your hardening, which could help us determine where it's at. The other possibility is that the blade may have been overheated during hardening which can cause grain growth. Overly large grain structure can also make for a weak chippy edge. When thinking of large vs small grain, and how it effects edge stability, think of playdoh with sand in it as fine grain, and playdoh with gravel in it as course grain. The fine sand mixture will be able to be smeared out to a more acute angle without carbide or grain tear out. The gravel mixture can't get as sharp of an edge without the larger rocks tearing out or popping out if the mixture. Same goes for steal grain. Overly large grain can't sharpen down as fine or hold the stable edge because the larger grains tend to tear out rather than sharpen down.
Ya the etching was probably the scariest part. It's quite easy to burn through the brother stencils so it was nerve wracking in that do or die moment. I like the playdough analogy. Really helps with understanding everything I have read about the grain structure. Is it possible that some parts of the blade have a different grain structure then others? I did the brass rod test where you flex the blade against a brass rod and the edge came back to true everywhere in the blade exept for where I was getting chipping. I would think maybe I over heated that one area but it's in the middle of the blade. Not the thickest part and not the thinnest part so maybe I need to move the blade around in the forge more before quenching. For my tempering I did 3 hours at 300. I have since learned it would probably be better to do 3 1 hour cycles and air cool between but I didn't know if I could over temper so I didn't want to do a second round in the oven after I did 3 hours.
It sounds a bit like you got a hotspot when you did your heat-treat. I would bet that part of the blade was right under your burner flame in the forge. That spot was likely heated too far beyond critical when you quenched. It's important to keep the blade in motion and get a nice even colour across the whole thing.
