Destroying then Resurrecting a Serrated Edge (VID)

[mbhanzo]

I use it because it does keep the stone from loading
and keeps the little bits of metal in suspension and
off the surface of the stone to a degree. Its far from
messy and so far the best solution ive found.

 

[Jason B.]

DMT says DO NOT STORE IN KEROSENE, I'm guessing there is a reason behind this, but hey what does DMT know

 

[hardheart]

Yes the burr is part of the edge. But we call it a burr because it leans one way or the other. When I sharpen the left side of the blade, the burr appears on the right. This tells me that I have ground the left side until it met the other side.

If you only grind on one side, not only is your edge asymmetrical, you only have a flat grind on *one* side of your blade. You seem quite knowledgeable, so I think maybe my terminology confused you or something. If you don't grind both sides of the blade until you get a burr.. first on one side and the on the other... you won't even know that you have a flat grind on *both* sides of the blade that actually meets the edge.

Think of the blade as being round on both sides. Grind off the roundness on one side and get a burr. Now you have one flat side. Grind off the roundness on the other side and get a burr. Now you have two flat sides. This is the fundamental aim of sharpening.

notice that you said right off that the left side met the right side because of the burr. If the left met the right, then the right met the left. You only create a burr at the edge, and there is only one edge. The radius of the edge will increase as the edge wears, so that is the rounding, but the bevel does not round. If you sharpened it flat once, then it will still be flat on the bevel. If a burr forms, then you have decreased the radius of the edge enough for that thin, weakened metal to cause it. That is what I mean about the bevels not being even, the roundness on both sides is removed, because the edge shifts over to the opposite side as the radius is ground away, now off-center.

Then why does DMT say to use water and to never store in kerosene?

Well, they say

While we recommend you use DMT® products dry or with water only, it is acceptable to use a variety of lubricants when sharpening with DMT® products. Mineral oil, mineral spirits, kerosene, WD40 can all be used without harming your DMT® sharpener. We do not recommend storing your DMT sharpener in kerosene. DMT® recommends that you always wipe your Diamond and Unbreakable Ceramic Sharpeners clean and store dry after use.

And I do not know why, other than to say that much of their product line is perforated plate mounted to plastic, and I certainly wouldn't store that in oil. They don't make a distinction, so I can't say if that's the reason for the blanket statement for whetstones, duosharps, diasharps, diafolds, aligner kits, diamondvees, and mini-sharps.

 

[mbhanzo]

These things come with instructions? LOL
I wonder if the kerosene thing is more directed
at the plastic interrupted surface stones. The Dmt
rep that runs their display at Blade and other shows
lives here in Ft. Wayne and stops to visit and get his
and his hunting buddies knives sharpened in the shop
about every other month. I'll ask him what he knows
about the kerosene warnings when I see him next. I'll
post whatever information I receive.

 

[hardheart]

that is from the FAQ on the website.

 

[mbhanzo]

I can only say that my stones love their
oil bath and I have no reason to believe
anything negative will come of things.

I've used other solvents over the years with
my diamond stones and never have I had a
single problem. In fact the only problem I've
ever had with a diamond stone have come from
the most current batch of Fallkniven Dc3 and 4
Diamond/ceramic stones. I'll get past the fact that
most of them are not glued up anywhere near even
or uniform or that even when they appear to be glued
correctly that some fall apart in wet or dry situations
but rather my one and only big problem has been
the diamond plated surface blistering, peeling off.
I've never had another problem and none ever with
a Dmt product.

 

[Arpaio]

Great vids. I'm constantly trying to refine my sharpening technique and these videos definitely gave me a few things to keep on mind. I appreciate it.

 

[Staid]

With a serrated edge it would be better to flat grind the back side instead of using a secondary bevel and taking off a excessive amount of the teeth.

I was wondering about the teeth too when watching the video. Would it loose some cutting power if teeth are not as sharp/high as they use to be? How many times is it possible to use this method before all the serrated edge is gone, or at least so much is wasted that its not working effectively anymore?

 

[mbhanzo]

I was wondering about the teeth too when watching the video. Would it loose some cutting power if teeth are not as sharp/high as they use to be? How many times is it possible to use this method before all the serrated edge is gone, or at least so much is wasted that its not working effectively anymore?

This is a fair question... One could completely flat grind the off side of the blade if the off side was flat ground to begin with but the knife in question was hollow ground and completely flat grinding the blade would indeed remove much more material than needed.. The reason for creating the smaller secondary bevel on the off side of the blade is that it is removing less material and doesnt change the overall blade geometry as much as one would think.. This method works and works very well. As far as how many times this is needed and to how long the serrations will last all depends on how deep the serrations were ground in the first place and how often major regrinding is needed.. Once a proper back bevel is formed very little material will ever need to be removed in general touch up type sharpenings.. Everyblade has a service life. If you misuse and abuse the knife your expected service life will obviously be much shorter..

 

[matt321]

Cool videos. Nice shop. Good explanation of serrated edge advantages (I still like un-serrated for my carry). You guys did a nice job on these. Thanks for the show.

Sharpening the back side of the serrations is the way I was taught to do this. I can't remember who taught me this...maybe Dave Martel.

 

[mbhanzo]

Thanks guys for the positive remarks on the
video. We will be making a couple very soon that
will go into more detail and hopefully we'll get
our hands on a camera that will allow us to
show better detail of the edges as we go through
the grits. The belt used to grind the edge on the
serrated knife was a well worn 120 fine aluminum
oxide stone from Sears I first started using the
4x36 belt grinders/sanders over 15 years ago and
they simply work awesome. They are not perfect
but I've found I can grind a beautiful flat or convex
grind with it. Some blade types and styles require
a bit of creativity in how you go about grinding
them but the machine will do all. I also have a terrific
old blademaster grinders that runs the favored 2x72 belts
and do also often use this machine but nothing I've found
to date will ever replace the 4x36 horizontal machine for the
majority of my edge grinding needs.

 

[dericdesmond]

hopefully we'll get
our hands on a camera that will allow us to
show better detail of the edges as we go through
the grits.

You doggin the cam foo? I thought it worked pretty well. Now that you have offspring maybe it would be wise for you to buy one, punk.