The first sharpening

Jason B.

Jason B.

Joined
Jun 13, 2007
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The first sharpening of a knife when you decide to set your own bevel, fix damage, or simply make it sharper always sounds a lot easier than it often is. A factory bevel usually set in place by a belt sander of some sort is very fast but not much for precision, if your lucky enough to get a bevel where the curve of the blade has been properly followed and even pressure was used things are not so bad but that's very rare. Often when you start grinding you see high and low spots on the bevel that have been created by the uneven use of pressure from the factory belt grinding. Along with inconsistent angle control, recurving starting after the choil, obtuse angles, and excess removal of metal all make for a long day when trying to make your edge right.

I've been given the chance to sharpen a high end knife and thought it would make for a good example and thread, it was actually the idea of a new member and owner of said knife so Rick this ones for you :)



The knife is a CRK Umnumzaan and I must say it was one of the nicest factory bevels I have ever seen. High level of sharpness and very even grinds. I decided to start with a coarse DMT as there was a minor deformation and the factory finish was finer than normal and did not need a coarser stone.

Factory edge.
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Small deformation.
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Coarse DMT
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Fixing some incorrect angles near the choil.
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And correcting a very small recurve just in front of it.
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After all that was done it was time to move on to the Fine DMT.
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Not a big change but it did its job to allow me to move to my next stone, the EF DMT. This is the point where you start to see a improvement in finish and sharpness.
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Now this is where I changed things a bit and used the DMT suggested way of sharpening. After the EF stone I used the 6 micron diamond paste on hardwood. you can see a little paste on the bevel :)
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And after the 6 micron
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From here I used the EEF stone to refine the bevel even further though the scratch pattern was finer the stones tend to cut deeper.
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Lots more to add but its my bed time so I'll see ya all later :D
 
cool thread, some more pics in the morning then?
do you go over the dmt stones at an angle? the scratch pattern after the coarse stone says you do..
if so, why wouldn't you go over the stone with the edge perpendicular to the length of the stone? is there any advantage?
 
zyhano said:
cool thread, some more pics in the morning then?
do you go over the dmt stones at an angle? the scratch pattern after the coarse stone says you do..
if so, why wouldn't you go over the stone with the edge perpendicular to the length of the stone? is there any advantage?
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No reason really, it just happens that way from my sharpening technique.
 
somehow I think the bf guru of sharpening must have a reason for that..:)
Are you saying you just found another thing in your technique that you can think about and improve it so that it might help you get even sharper edges? :D
 
Its just the result of sharpening at a near 90 degree angle to the stone. It also has a little to do with me starting at the choil and moving to the tip, if I started at the tip and moved to the choil the scratch pattern would look different. As you will see, the scratch direction will have little to do with the final product.
 
Hey Knifenut - do you ever worry that a knife you have sharpened might start cutting the fabric of time & space? Seriously - you do some nice work!
 
Yeah, I'm going to have to agree! Those edges look ridiculous! You definitely have your art mastered....well done:thumbup:
 
All was looking good until I got to the 3 micron paste and realized I needed to go back to the stones :(

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Sometimes even when you think you did it right and the finish looks good the polishing will always bring out the flaws. So I went back to my fine stone and worked the process all over again, it is without a doubt a PITA because no one wants to redo all the work that they just did but its just something you must do sometimes.

At first I was going to stop at 1 micron because I find it to be my happy medium for most steels but the excellent heat treat and hollow grind made me push this one a little further.

1 micron finish
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This was about half way through the use of the 1 micron strop, at this point the edge stills has a lot of a toothy like bite to it but is very smooth. It will treetop, whittle, and draw blood at the slightest touch :eek: but sometimes that's just not good enough :D

The next step was the 0.5 micron strop, this is where things start to get interesting with sharpness. The edge turns from toothy to sticky, and so far that's the only way I know how to describe it. If the edge is thin enough a finish at this level will give you a shave nearly as smooth as a razor and cut things in a way you never thought a edge could.

Truthfully edge retention improvements really don't get much better after around 8-10k but that doesn't mean you still can't get the knife to cut better :)

0.5 micron finish
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We all lust after a great finish on our edges and work so hard sometimes to get them but just like a fresh paint job its only perfect for a moment. When you get a piece of metal or any surface that can be polished and take it to a extreme level of finish the slightest things like dust in the air that has landed on your strop can make you very :(:(:(
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Though you can hardly see these marks with the naked eye its still upsetting sometimes because you tried to make it be as perfect as possible. The quest for perfection and the sharpest edge is never ending, if you do it by hand or with a jig your results will always vary a bit simply because of you body mechanics. Things like the food you eat, how much coffee you drink, your mood and many other small factory will all play into the outcome of your edge.

Well that's all for now, I'll put up a final pic of the edge after the 0.25 finish I have planed for this blade :eek: then we will talk about pressure points ;)
 
Does getting the blade to such a mirror finish serve a purpose? Don't you want the micro-serrations, or do put too much stock in Spyderco's Edge-U-Cation?
 
speedfan said:
Does getting the blade to such a mirror finish serve a purpose? Don't you want the micro-serrations, or do put too much stock in Spyderco's Edge-U-Cation?
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Sure, you can shave your face with it =) Besides that, germs can't survive on polished steel, it doesn't trap material for germs to grow on. It's also easy to clean. I'm not a fan of micro-serrations, for certain steels they just create stress risers increasing probability of chipping.
 
speedfan said:
Does getting the blade to such a mirror finish serve a purpose? Don't you want the micro-serrations, or do put too much stock in Spyderco's Edge-U-Cation?
Click to expand...


Think of it like this, do you really want deformed bit of metal hanging off the end of your edge or would you like the edge to be a V of solid metal?
 
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