Serrated knife, serrations angle?

[SharpenADullWitt]

I've read about sharpening a serrated knife on the grinding wheel then buffing it and what I saw sounded like buffing it between the serrations on the buffing wheel.   What angle are serrations typically or is there a typical?


Thanks

[jeffs55]

You cannot sharpen a serrated edge knife with any degree of consistency on the Tormek using any of the attachments offered and certainly not freehanded.

[Stickan]

Some serrated knives has an small angle on the blades backside, that you could sharpen but as Jeffs55 writes, there is no easy way doing this.

[Jeff Farris]

So, I've been doing the impossible for 20 years? 

Most serrated blades are hollow ground on one side and beveled on the other. The hollow ground sound appears flat, but rarely is. Even in those cases where the flat side is truly flat, the hollow from the Tormek wheel will not alter the knife's performance.

Grade the stone fine, being careful to get a completely smooth surface. Freehand grind the hollow grind, keeping it as flat on the wheel as possible. Then use the corner of the leather honing wheel to work in and out of each tooth on the beveled side. Don't worry about what the angle is, just follow what's already there. Hone the hollow ground side as well.

Now, the caveat is, this only works on knives that are dull, not on ones that are nicked or damaged. But to whitewash the issue with the statement than you can't possibly sharpen a serrated knife of any kind or condition is misleading.

[SharpenADullWitt]

So no idea of the standard angle of the gullets then?

[jeffs55]

So, I've been doing the impossible for 20 years? 

Most serrated blades are hollow ground on one side and beveled on the other. The hollow ground sound appears flat, but rarely is. Even in those cases where the flat side is truly flat, the hollow from the Tormek wheel will not alter the knife's performance.

Grade the stone fine, being careful to get a completely smooth surface. Freehand grind the hollow grind, keeping it as flat on the wheel as possible. Then use the corner of the leather honing wheel to work in and out of each tooth on the beveled side. Don't worry about what the angle is, just follow what's already there. Hone the hollow ground side as well.

Now, the caveat is, this only works on knives that are dull, not on ones that are nicked or damaged. But to whitewash the issue with the statement than you can't possibly sharpen a serrated knife of any kind or condition is misleading.

Now we know why Jeff Farris is the administrator and I am not. My serrated knives are not worth the time as I imagine this to be quite time consuming. My "expensive" serrated knife cost about $15 and the only reason that I paid that is that it has a 14" blade. Even in that case, I would not take the time to resharpen it. All that it is used for is bread and or doughy stuff and should last a longgggggggggg time.

[Herman Trivilino]

There is no standard angle.  The flat side is at a bevel angle of about 10^o on my mine, and I have sharpened it successfully free hand.  The next time it needs it I will use my HK-50.  It's the only jig I know that'll go to that small of a bevel angle.

[SharpenADullWitt]

No standard angle on the gullets, ok.

Tormek was/is going to be my second step.  BEFORE getting to grinding on the back, I was planning on making a fixture and running down the gullets, (with an inherited sharpener that is the correct size for them), then doing the Farris described method. (flattening the back then honeing on the wheel)
The Tormek part seems like it should be the easy part, and my thoughts were I could make something that referenced a standard angle for the gullet tool. (less chance of me buggering them)

[Herman Trivilino]

You will just have to try to match the existing angle the best you can.

Don't forget the basics:  Good light is essential.  Magnification helps a lot.

You can grind a bit, then examine to see how close you are to the existing bevel angle.  It helps to color the bevel with a marker so you see how well your grinding angle matches the existing angle.

[Ken S]

It may be heresy on this forum, however, I just sharpen the gullets.  I use a dowel covered with self stick abrasive.  It's easy to eyeball.  Your sharpener would probably work at least as well, and maybe better.  I don't grind the flat side at all.

Herman makes a good point about using the black marker.  I would recommend just turning the wheel by hand when using the black marker.  That's enough to indicate whether the angle is set right or not.

Ken

[wootz]

Albeit an old topic, this info can still be of interest.
CATRA actually measured angle in the serrated knives scallops, it is 18-25 degrees.
I don't have unchanged serrated kitchen knife, but measured half a dozen of pristine pocket and tactical with serrations, and the scallop angle in them is commonly 23-25 degrees, and in one occasion 18 degrees.

[SharpenADullWitt]

Though this is an old topic, this info can still be of interest.
CATRA actually measured angle in the serrated knives scallops, it is 18-25 degrees.
I don't have unchanged serrated kitchen knife, but have half a dozen of pristine pocket and tactical with serrations, and the scallop angle in them is commonly 23-25 degrees, and in one occasion 18 degrees.

May be an old topic, but I could never find that answer!
So THANK YOU, THANK YOU, THANK YOU!!!!!!!!!!!!1

My view is there are times I will still want to use either the paper on the dowel concept, or a tapered diamond sharpener I have as the knives wear, to extend their life. (in addition to the Tormek)
So this is of use to me!!!!!!!!!!!!

[Ken S]

Interesting observation.

Ken

[wootz]

SharpenADullWitt ,
I also used a tapered diamond sharpener to work individual scallops, then switched to Dremel, and still not happy.
Serrated blades keep haunting me.
Quality methods are slow, and quick methods smooth away serrations.

[Ken S]

Wootz,

If you are sharpening professionally, I would charge according to the actual time involved. If it requires fifty percent more average time to sharpen a serrated knife, add fifty percent.

Jeff Farris posted a quick method several years ago.

You might want to consult Steve's DVD. He has a very good section on sharpening serrated knives.

Ken