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Converting Serrated Blades to Straight?

Started by harrski, December 13, 2010, 07:51:05 PM

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harrski

I have several JA Henckels serrated edge knives that are no longer sharp.  Basically they are now trash, unless I can convert them to straight edge.

I recently purchased a T-7 and in the past few hours sharpened evey knife I own to razor sharpness!  I started with an old kitchen knife that would not cut a thing and it can now slice anything paper thin. Next on the list are my wood working chisels.  The machine is simply amazing! 

Has anyone converted a serrated edge knive to a straight edge?  If so did it work and how well?

Thanks in advance
-Eric



Jeff Farris

It's no problem at all. Depending on the blade style, you may want to thin the blade a bit. In general, just grade the grindstone to the aggressive cut, and keep grinding until you have the shape you want.
Jeff Farris

brettgrant99

What is a good technique to "thin" the blade?

Thanks,
Brett

Steve T


I just sharpened a JA Henckels serrated paring knife last weekend.  I was debating as to wether to remove the serrations altogether, or try to preserve the knife profile.  If you use a magnifying glass to look at the edge opposite the serrations, you will notice that there is a slight edge angle.  I sharpened this side only (at 25 degrees) using a fine graded stone.  It worked quite well.  If it didn't work, I would have removed the serrations.

Steve

Jeff Farris

Brett,

Just lay the body of the blade against the grindstone and go for it. Coarse first, then fine, then polish the blade with the leather honing wheel.

Steve,

I've covered this before, but it is buried pretty deep in the old threads. Sharpening serrated blades is very doable, even more so if it is done on a maintenance schedule.

Almost every serrated knife is made with the bevel cut on one side and the other side is either flat, or as Steve has found, has a very small bevel (though that is rare, most are flat).

I've had the best results by backgrinding (grinding the full surface of the flat side) and then honing on the leather honing wheel. You can follow the contours of the serrations on the corner of the leather honing wheel by riding the very corner in and out of the profile.
Jeff Farris

harrski

Thanks Everyone.  I'll give it a go and post my results. 

harrski

Well it took a while until I got around to it, but I took Jeff's advice and it worked perfectly.  I ground the back side and then honed both sides using the leather wheel and the knives are once again razor sharp. Thanks everyone.

GIPPER

Jeff F.
When you are back-grinding the flat surface of the serrated knife, how to you account for the grinder's arc surface and the flat back surface of the knife?

Would your description also apply to sharpening serrated scissors?

Gipper

Jeff Farris

The backgrind (flat side) of a serrated knife is rarely, if ever, actually flat. It is hollow ground. Usually on a grindstone near the size of the Tormek Grindstone.

If you're talking about pinking shears and patterned scissors, then, no, those suggestions most certainly do not apply. Sharpen those on the bevel only. Use the marker method to find the bevel angle, which will be quite flat -- in the 70 to 80 degree range.
Jeff Farris

Ken S

Is there a good reason not to restore the knives as serrated?  I recently sharpened my Henckels serrated bread knife using micro abrasive (3M high tech sandpaper) wrapped around a dowel.  For smaller serrations, a file or triangular piece of wood with diamond paste should work.

Ken

Herman Trivilino

We're keeping the serations!  The grindstone touches only the flat side of the knife.  The other side (the side with the serations) touches only the honing wheel.  Of course, your technique would be a huge improvement, as you are grinding both sides.
Origin: Big Bang

Ken S

This post and answers should help you.  Several methods are suggested.  I am modestly partial toward my suggestion, as it is how I sharpened my scalloped bread knife.  It worked very well, although the actual sharpening took longer, perhaps ten minutes.

Ken





Quote from: harrski on December 13, 2010, 07:51:05 PM
I have several JA Henckels serrated edge knives that are no longer sharp.  Basically they are now trash, unless I can convert them to straight edge.

I recently purchased a T-7 and in the past few hours sharpened evey knife I own to razor sharpness!  I started with an old kitchen knife that would not cut a thing and it can now slice anything paper thin. Next on the list are my wood working chisels.  The machine is simply amazing! 

Has anyone converted a serrated edge knive to a straight edge?  If so did it work and how well?

Thanks in advance
-Eric

Elden

Usually the points of the serrations are what are dinged. As Ken, I like touching up that side as well especially if it has been abused. I do like the idea of the dowels as the size would be consistent versus the tapered diamond coated steels that I use. The tapers are nice because they fit a wide variety of serration sizes. A person has to be careful not to stroke too far into the larger portion of the taper thereby altering the serration profile.
As a touchup, I can see the other point of view and will have to give it a try.
Elden

Herman Trivilino

We have a cheap Ecko brand bread knife that we've had for years.  By removing a bit of steel from the flat side and touching it up on the leather wheel I revived it.  It cuts bread good enough for us and will probably last us for many more years.
Origin: Big Bang

grepper

#14
I like that Herman!  "...cuts bread good enough for us..."

I have a bunch of knives, pruners and metal shears that will never be perfect again.  But perfect or not, I've revived most of them to be completely enjoyable and useable tools, adding many years to their life.

Funny how tools pile up that are too dull to use, but too good to discard.  Often they are simply replaced with new... How sad.  Some are beautiful old American made shears and snips, that with proper care and occasional sharpening will last many, many years to come.

And so as not to get off subject,  :), I have an old cheapo serrated Ginsu steak knife that my wife got for free something like 25 years ago by signing up for credit card.  It is the lone survivor of a set of 6.   I love the old thing!  I _still_ use it every day.  After all that time cutting bricks, nails and tomatoes, it started to get just a little less effective.  A couple of seconds on the T-7 and it's now razor sharp again.

After reading this post I could have done it a little differently, but nonetheless, once again, it can cut through a nail and then slice a tomato paper thin.  Think of the savings!  I can make a tomato last for 100 sandwiches!