Ran into an annoying problem

L

Lone Fortress

Joined
Aug 20, 2013
Messages
82
Well-after several very unsuccessful attempts, I still can not get decent edges on my knives.I believe I'm literally doing everything by the book (John Juranitch's Razor Edge book of Sharpening)-getting a burr formed along the lenght on both sides, switching to the fine side of the hone and then taking light even passes at a slightly raised angle.

I'm using a cheap Smith&Wilson diamond coated hone from Walmart-as there's no hunting stores nearby (well there is-but ironically, there selection was even worse), but I assume that's not the problem as it removes steel just fine. The blade can not push cut paper, seems to be an excessive amount of friction when cutting cardboard and light plastic and material sticks to the edge. What could be the problem here, if this question is even possible to answer?

I suspect that another, finer stone would help with the later problem-but I believe it still should be better then it is now.
 
Last edited:
Once the burr is established (on both sides), I switch the hone over to the fine side, and take light even passes at a angle slightly higher then the one used to form the burr in a forward direction only (as if making a slice on the stone).
 
bittermanbrewing said:
it can also just be the cutting geometry of the blade itself.
Click to expand...

I've considered that as well, but I've tried this so many times that the geometry has basically changed. It was a hollowgrind, but is more of a flat now. I might give sandpaper I try, but what backing should it have?
 
Before you go to making and edge, you need to make a bevel. If the knife is too thick at the edge, a perfect edge still will barely cut. Go back and check that the final bevel shaping left the knife almost sharp. It should be only a few thousandths of and inch wide at the edge before you start sharpening.

Beyond that;
Edge angle too high? - That would make the knife a poor cutter.
Edge angle too low? - That would make the edge very frail, and could chip out prematurely.
HT ????? - The HT can make the edge too soft and it won't stay sharp beyond a cut or two, or too hard and it chips out fast and won't cut paper at all.
Overheating the edge in grinding/sanding? - Things get hot in milliseconds with sanding. The very edge can be ruined even when the blade still remains cool.
Heating the edge in sharpening? - Same as above. Belts grinders and power buffers/strop belts, etc. can ruin all your hard work.
Wrong steel type???????? If you are using some found steel, or the steel is not right for your equipment and abilities, all the sharpening in the world may not help.
 
I've reground the bevels around 2-3 times (as my grindlines improve, I go back and rework my older knives if able-this knife being one of them), getting them a bit thinner with each one. The steel is simple 1080 or 1084 I think. I don't have any hardness tester, so can't determine how the Ht went without putting the knife through use and I want it to have a good edge before I start that.
 
Using the procedure Chuck just gave, you should have no problem getting a properly haardened 1080/1084 knife sharp. Some photos and closeups might help.
 
At this point, I think it's going to be the Ht that's the issue. The knife is only being abraded away now as the ricasso is now a bit lower then the edge and there has been no change at all in its degree of sharpness. I'll still reform a burr and strop it see if that makes any difference though.
 
I have never found that a diamond stone removes the burr on it own, there is always a small one left. Try stropping on a leather strop loaded with compound. If you don't have a strop wood, cardboard, newspaper will work to remove the burr.
 
I've stropped the edge a bit and material seems to no longer be sticking to it-but that's about the only improvement I'm noticing.
 
Go to the dollar store, the one where everything is $1, grab a handful of $1 chef knives and practice on those before you ruin a good knife. Best $10 I spent learning how to sharpen. I can finally get hunting knives hair-popping sharp and kitchen knives that will barely pop hairs but will cut tomatoes all day long and never seem to get dull.
 
My guess at this point is a blown HT. Likely overheated and likely very coarse grain that will never behave properly.

Move on. Try similar techniques on other knives to determine whether it's you or the tool. Personally I say don't waste any more of your time on cheap knives from the dollar store. Only quality steel/HT will support your efforts and give you proper feedback as you learn how this works. Avoid the additional frustration of "finest surgical steel" that stands practically zero chance of supporting the geometry you are shooting for.

Get control of your HT temps and try again. Best to you.
 
I'll give one final attempt before moving on, going to try to regrind the relief as thin as I can without overheating it then completely resharpen. If that doesn't work, I might just grind the edge and point off then (carefully) break it to see how the Ht went.
 
Lone Fortress said:
I've reground the bevels around 2-3 times (as my grindlines improve, I go back and rework my older knives if able-this knife being one of them), getting them a bit thinner with each one. The steel is simple 1080 or 1084 I think. I don't have any hardness tester, so can't determine how the Ht went without putting the knife through use and I want it to have a good edge before I start that.
Click to expand...


What concerns me here is the "I think" part of your steel description. No offense, but it sounds like you're just guessing. Is this scrap steel?


Did it skate a good file after you hardened it? I can't see how you'd miss temper so bad within any of the normal ranges that it'd give you an unsharpenable knife, so you either a) are trying to harden mild steel or something that requires complex HT regime, b) never got it hard in the first place if it actually is a simple 10 series high carbon steel. or c) are really screwing something up in the grind/sharpen.


I'm also concerned that you seem to be calling every non-powered sharpening instrument a "strop". Sharpening stones (diamond, ceramic, natural, whatever) and strops are different things.


Still, if you're getting an actual burr, you should be getting a decent edge. You can knock a real burr off with just about anything. Which leads me back to the steel. Do know it's 10something, or do you just hope it is?
 
It isn't scrap steel, but I've so far tried 2 steel tyles-01 (which I moved away from for now) and 1080. I haven't been keeping records of which is made of which. I know that a camper I attempted is made of 01 and my most recent knives are 1080, but I don't quite remember which this particular knife is from. Either way, it seems to be a Ht issue as the blade is just being abraded away at this point leaving me the impression that it's as sharp as it'll get. Either that, or the relief is still a bit too thick.

I've only used the word strop once in this thread which was on post #13.
 
My last post isn't wanting to edit for me, so I'll add a update to this post. Went back to one of my more recent knives-which has a much better relief behind the cutting edge, managed to get it much sharper then the one this thread is referring to-but still not as sharp as I'd like and it didn't last for long (as in, it dulled after only 1-2 cuts). I noticed that a slight bend formed in the tip as well. After noticing this, I then took my worst knife (one that I know is made from 1080) and broke it. The blade bent a significant amount before breaking and has a very noticable grain. Since I clearly am not ready to be working in batches and the horrid accuracy of my Ht, going to be making quite a few changes for next time.

The main problem is the Ht as nearly everything is limiting me, my funds, my space and my equipment. I'm limited to a one brick forge using a Bernzomatic torch with MAPP gas as the heat source. Giving that, what could I do to help prevent this from happening again? I know that a magnet would help to determine when austenizing temp is reached (Yeah..I foolishly didn't even use one as I don't know where to get one that's suitable, thought about getting one from a old speaker, but not sure if that'll work), but what else?
 
Last edited:
You must log in or register to reply here.
Back
Top