Broke new ground sharpening serrations...if you're a SE fan, you need to read this

[RLR]

Old version of this product had 1/8" ceramic rods that fit into the Dremel chuck. Low speed, perfect size and shape for serrations. Don't know if this new version has removable rods. Worth a look:

http://www.gatcosharpeners.com/product/ ... DQ1QTIQPX4

[bpeezer]

Old version of this product had 1/8" ceramic rods that fit into the Dremel chuck. Low speed, perfect size and shape for serrations. Don't know if this new version has removable rods. Worth a look:

http://www.gatcosharpeners.com/product/ ... DQ1QTIQPX4

I'm sure they could be removed if someone was motivated enough :D

[jackknifeh]

I'm really not worried about hurting the temper, the blade gets hotter when you make a few long fast cuts through cardboard than it does from the stropping. Besides, most of the SE knives I've done this with were H1, were the heat treat isn't an issue. Suffice to say, more heat gets into these blades when the serrations are cut in the first place than when I run a Dremel over them, and you don't hear people being concerned about losing temper from Spyderco sharpening them do ya?

When does the heat treating take place in the process of making a knife. My understanding is the blades are cut and shaped even to the point of creating the grind (saber, FFG, hollow, etc.) and then heat treating them. I think the steel is easier to grind before heat treating. Then the only thing to do is sharpen the edge after the heat treating. If this is true I wonder if the serrations are cut into the blade edge before or after the heat treating. I don't know because the serrations are just one bevel with no micro bevel at the edge apex. Does anyone know when the serrations are cut into the edge? If done prior to heat treating it wouldn't matter how hot the steel gets I don't think.

Jack

[Evil D]

When does the heat treating take place in the process of making a knife. My understanding is the blades are cut and shaped even to the point of creating the grind (saber, FFG, hollow, etc.) and then heat treating them. I think the steel is easier to grind before heat treating. Then the only thing to do is sharpen the edge after the heat treating. If this is true I wonder if the serrations are cut into the blade edge before or after the heat treating. I don't know because the serrations are just one bevel with no micro bevel at the edge apex. Does anyone know when the serrations are cut into the edge? If done prior to heat treating it wouldn't matter how hot the steel gets I don't think.

Jack

Not sure on the serrations, but regardless there's still more heat created when they cut plain edge bevels than using the Dremel. Heck there's more heat created in regrinding a chipped tip or modded a spine or something like that. We're talking about way less heat than even a regrind creates and that's covering the entire blade usually. The only heat part I'd be concerned about is burning the very edge, but again there's no more heat on the very edge than there is during belt sander sharpening that Spyderco does at the factory.

[jackknifeh]

Not sure on the serrations, but regardless there's still more heat created when they cut plain edge bevels than using the Dremel. Heck there's more heat created in regrinding a chipped tip or modded a spine or something like that. We're talking about way less heat than even a regrind creates and that's covering the entire blade usually. The only heat part I'd be concerned about is burning the very edge, but again there's no more heat on the very edge than there is during belt sander sharpening that Spyderco does at the factory.

When I ground my Manbug spine to resemble a Jester I used Dremel's tungsten carbid bits along with some of the "cut lube" and there was hardly any heat generated at all. But if I had used the grinding stones even with the cut lube the steel would have gotten real hot I think. Some cutting materials create more heat than others it seems. Funny story I think. Wife used my drill to remove a screw from wood one time. The tip was magnetic so when the screw came out it stayed on the tip. Not realizing how hot some screws get whan spinning in wood she just grabbed ti. :D :D :D Her reaction was a kodac moment. :) It's funny how funny this stuff is when it happens to someone else. :D Anyway, I have no idea how hot the blade would need to get for the temper to be damaged. Even if the steel is really warm but could still touch it would that harm the temper? Just curious because I'm not going to let any of the blades I mess with get even close to being hot just to make sure. I wonder in the wild wildd western days when those guys were constantly digging bullets out of each other if they damaged the heat treat of their knives by leaving them in the fire till they were red hot. :) Not only that, they take that red hot blade and stick it in the bullet hole in their friend. :eek: :)

Jack

[bpeezer]

When I ground my Manbug spine to resemble a Jester I used Dremel's tungsten carbid bits along with some of the "cut lube" and there was hardly any heat generated at all. But if I had used the grinding stones even with the cut lube the steel would have gotten real hot I think. Some cutting materials create more heat than others it seems. Funny story I think. Wife used my drill to remove a screw from wood one time. The tip was magnetic so when the screw came out it stayed on the tip. Not realizing how hot some screws get whan spinning in wood she just grabbed ti. :D :D :D Her reaction was a kodac moment. :) It's funny how funny this stuff is when it happens to someone else. :D Anyway, I have no idea how hot the blade would need to get for the temper to be damaged. Even if the steel is really warm but could still touch it would that harm the temper? Just curious because I'm not going to let any of the blades I mess with get even close to being hot just to make sure. I wonder in the wild wildd western days when those guys were constantly digging bullets out of each other if they damaged the heat treat of their knives by leaving them in the fire till they were red hot. :) Not only that, they take that red hot blade and stick it in the bullet hole in their friend. :eek: :)

Jack

From what I've read, with quenched steel you have to get to at least 300 degrees F before you start seeing a reduction in hardness. This will certainly be too hot to touch, so my rule of thumb is to keep one hand on the blade while I'm grinding it. That way I'll have to stop long before the temperature begins to affect the temper.

[Evil D]

From what I've read, with quenched steel you have to get to at least 300 degrees F before you start seeing a reduction in hardness. This will certainly be too hot to touch, so my rule of thumb is to keep one hand on the blade while I'm grinding it. That way I'll have to stop long before the temperature begins to affect the temper.

That's the rule I've always heard and used myself, once you feel the blade getting warm, do something about it. When I Dremel the serrations, I don't stay in one spot long enough to make enough heat for it to be felt through to the other side of the blade, so no heat problem to worry about.

[jackknifeh]

That's the rule I've always heard and used myself, once you feel the blade getting warm, do something about it. When I Dremel the serrations, I don't stay in one spot long enough to make enough heat for it to be felt through to the other side of the blade, so no heat problem to worry about.

When you say Dremel the serrations are you using an abrasive on a felt wheel or are you using a grinding stone or something like that?

Jack

[Evil D]

I'm using a cotton wheel loaded with polishing compound, check out the pics on page 3.

[Cliff Stamp]

From what I've read, with quenched steel you have to get to at least 300 degrees F before you start seeing a reduction in hardness. This will certainly be too hot to touch, so my rule of thumb is to keep one hand on the blade while I'm grinding it. That way I'll have to stop long before the temperature begins to affect the temper.

This argument has been used by many makers and manufacturers, especially in defense of uncooled power grinding since Roman Landes started speaking out about the damage it causes.

This seems to make sense as obviously 300 F is long past the point that your skin starts to burn. Even a 140 F exposure will produce three degree burns in seconds on bare skin.

However the problem is that the argument ignores several critical aspects of physics :

a) steel can be damaged if exposed to high temperature even if the exposure time is very small (as in under a second)

b) the edge itself will heat sink (cool) rapidly through the main body of the blade producing a temperature gradient

The second part essentially means that the very edge can be MUCH hotter than the blade behind it. This means you can easily keep your hand on the blade, even right on the part getting ground (a bit dangerous) and you can over heat the edge and not burn your hand.

It is in fact easily possible to over heat a blade to the point it will turn dark blue to black and you can still do it with your hand on the blade. It is just a false sense of security, there is simply no way to use your hand to constrain the temperature of the very edge.

For a little materials data :

https://drive.google.com/file/d/0B3dKJo ... sp=sharing

That is an over heated blade (picture from Roman Landes) and even though the heat damage is 5 HRC points, it is limited to a height of under 1/10 of a mm.

This also isn't the only way they get damaged as the other thing people do is violently water quench the steel which is not suitable for many steels and even for the steels it should be used on, it isn't meant to be done when the edge is sharpened due to the cracks that the violent expansion and contraction will make.

In short if you have to power grind and are unwilling to use a continuous coolant then :

-use high quality and fresh abrasives, ideally CBN (it grinds cooler)
-apply low force and low speed
-use a coolant on the blade before it hits the abrasive
-let it air cool after grinding before coolant is applied

and be very aware that you have no way at all to know if the edge is damaged or isn't.

[bpeezer]

Thanks Cliff, I guess I should have mentioned that you shouldn't use that rule of thumb as a guide for sharpening, more for if you want to grind a blade after heat treatment. As both you and Evil D have mentioned the thin edge does heat up much faster than the rest of the blade. I burned the edges of quite a few cheapo hardware store knives learning that lesson :p

[zhyla]

Finally got around to trying this so time to necrotizing this thread. Had some greenish polishing compound in my Dremel kit. I know nothing about polishing compounds so no idea if it was appropriate. I sharpened on medium, fine, and ultra fine Sharp Maker stones and then polished both sides with the Dremel.

It seemed to do the trick. The success was a little variable. All the knives showed an improvement but the ones with more abused edges (I've got a Rescue Jr that needs a lot of work) seemed to benefit the least. A VG-10 Delica that has a good edge to begin with came out amazingly well. So impressed.

The dremeling takes really no time at all. I should probably get some decent polishing compound an dial this process in.

[Evil D]

Finally got around to trying this so time to necrotizing this thread. Had some greenish polishing compound in my Dremel kit. I know nothing about polishing compounds so no idea if it was appropriate. I sharpened on medium, fine, and ultra fine Sharp Maker stones and then polished both sides with the Dremel.

It seemed to do the trick. The success was a little variable. All the knives showed an improvement but the ones with more abused edges (I've got a Rescue Jr that needs a lot of work) seemed to benefit the least. A VG-10 Delica that has a good edge to begin with came out amazingly well. So impressed.

The dremeling takes really no time at all. I should probably get some decent polishing compound an dial this process in.

You have to be veeeeeeery careful to not increase the angle too much, or you round off the edge. You have to do it the same as you would with a standard strop, so keep on mind that on a strop if you lift the blade too much you round off the edge. With the Dremel it's even easier since it's going so fast.

Since this thread I bought a Sharpmaker and I use it for my serrations but I still use the Dremel to finish the edge.

[JAfromMN]

Interesting.

I may give that a try on one of my user one day

I wouldn't dare take the Dremel to one of my nice ones. I learned that the hard way.

[Evil D]

Interesting.

I may give that a try on one of my user one day

I wouldn't dare take the Dremel to one of my nice ones. I learned that the hard way.

Just curious but what did you do to learn that?

When you hit the edge, try to match the angle of the serration itself, not any micro bevel or whatever that you use on the Sharpmaker. The buffing wheel has enough fibers sticking out that they'll bend and hit the edge. It doesn't take much to get the job done.

[JAfromMN]

Interesting.

I may give that a try on one of my user one day

I wouldn't dare take the Dremel to one of my nice ones. I learned that the hard way.

Just curious but what did you do to learn that?

When you hit the edge, try to match the angle of the serration itself, not any micro bevel or whatever that you use on the Sharpmaker. The buffing wheel has enough fibers sticking out that they'll bend and hit the edge. It doesn't take much to get the job done.

Oh I tried to fix a delica or 2 after i ruined the serrated edge on nails and bed springs. I used to work in a hotel.


I'm going to try your method when I dull one.


I think you may be on to something.

I use the 701 profile set and strop my edge with leather shoelace. It works good for me.

[DougC-3]

Interesting.

I may give that a try on one of my user one day

I wouldn't dare take the Dremel to one of my nice ones. I learned that the hard way.

Just curious but what did you do to learn that?

When you hit the edge, try to match the angle of the serration itself, not any micro bevel or whatever that you use on the Sharpmaker. The buffing wheel has enough fibers sticking out that they'll bend and hit the edge. It doesn't take much to get the job done.

Oh I tried to fix a delica or 2 after i ruined the serrated edge on nails and bed springs. I used to work in a hotel.


I'm going to try your method when I dull one.


I think you may be on to something.

I use the 701 profile set and strop my edge with leather shoelace. It works good for me.

That piques my imagination... maybe trying to get an innerspring mattress cut down to dumpster size, Ha Ha

I think stropping SE with leather shoe laces is damned innovative. I'll have to try that.

A couple of other thoughts: Actually "slicing wood" is what got me turned on to SE blades and the main thing I use them for. I don't just go out and cut brush with a folder all the time LOL -- I own loppers, hedge trimmers, even a Puller Bear (Made in Canada--which is amazing and can pull up 3-inch bushes and saplings and their 3-foot roots). But when I just happen to be out and only have a knife, an SE blade is great for lopping a stray limb or maintaining a trail. The escaped Chinese privet that covers much of the SE US never lets up and chokes out native plants. I guess it's a relatively soft wood, but my Pacific Salt or D'Allara Rescue can cut through an inch and a fourth limb with one stroke if you bend the limb and cut into the bend (sorry if you've heard me say this too many times before).

Once, I noticed that the edge was rolled on the H-1 blade and now use only the VG-10 D'Allara for this. I thought maybe H-1 was not intended for this sort of routine use, but I didn't do any controlled experiments, so somebody correct me if I'm wrong. I have to be really careful to avoid taking away too much metal when sharpening the H-1 on the Sharpmaker. Of course I try to go by Sal's instructions on the CD that came with it.

Anyway the D'Allara is great for this because of the comfortable, hand-filling grip. Also, the straight edge seems to work really well. I'd like to try the straight-edged, large-toothed Jumpmaster versus the curved, smaller-toothed Aqua Salt. I'd bet on the Jumpmaster. Sal once said, "Nothing cuts like a Jumpmaster."

[JAfromMN]

I still have yet to try buffing my edge with a Dremel

I worry its going to get to warm

I still might

[zhyla]

Don't worry about the heat too much. You're going to buff each serration for less than a second. If the blade feels warm at all just run it under some water cool it back to room temperature. The buffing doesn't warm up that much at all. I make kitchen knives so I do a lot of grinding on heat treated blades where the temperature is a big concern. I'm not worried at al, with the buffing.

[Evil D]

I still have yet to try buffing my edge with a Dremel

I worry its going to get to warm

I still might

More heat is generated in the grinding of the serrations than in buffing them.