The title says it all, really. How are you supposed to sharpen a serrated knife like a bread knife? Wouldn’t a normal sharpener kill the serration?
I’m not sure it’s possible… Part of the benefit of serration is that the blade stays sharper longer but I’ve always assumed once they finally dulled they were junk…
It’s a pain in the ass, but it can be done with the right type of sharpener and a buttload of patience.
It’s rather that the serration makes the sharpness of the edge less relevant. The jaggedness tears the bread.
Yes, a normal sharpener would - eventually - kill the serration, and in any case would be an utter pain to use on such an irregular edge. In my experience other things go wrong with breadknives before they need sharpening, like the handle breaking or the blade getting bent.
Here are two products that claim to do the job:
https://www.lanskysharpeners.com/lanskyxcart/product.php?productid=92
My 2 cents, as I work in the kitchen at a restaurant that uses 12" off-set serrated knives…
When we get a new knife that sucker will stay sharp for a really long time… when used properly. If you’re only using it on bread/meats w/ a proper cutting board, they’ll be almost as sharp a year later (after daily use) as the day you bought it.
The problem starts when a new hire or a server gets a hold of super-sharp, shiny-new knife and uses them without a proper cutting board or uses it on lemons/limes. I swear the skin on lemons/limes dulls a knife as quickly as cutting through a leather boot.
So to close out… I don’t know how to sharpen a serrated knife… but if you use it properly it WILL hold it’s sharpness a hell of a lot longer than a straight-edge knife. Hope that helped? 
The AccuSharp in your second link claims to sharpen serrated edges safely, but I wouldn’t trust it with any nice or even slightly expensive knife. You can see from this design drawing that it’s basically a V-shaped sharpening steel. I concur with the author of Q.E.D.'s link, that serrated knives should only be sharpened on the serrated side. The other side should not be ground at any kind of bevel; it should only be touched up on the flat. If your knife is an el-cheapo, then AccuSharp away, but if it’s a decent knife like a Henkels or Wusthof I wouldn’t use that.
Some knife makers will actually do sharpenings for you. Check with your maker to see if they offer that service. Years ago, I had a Spyderco whose plastic clip broke off when it caught on something while I was sitting down. I called the company to find out where I could get it repaired, and they sent me out a box with a shipping label. About two weeks later I got it back, nicely repaired and sharpened. They included an insert with services and charges for repairs and maintenance. If I remember right, sharpenings on the serrated blades were something like $5 plus shipping. I don’t know if they still offer that service, but if your knife is made by one of the better companies you can probably get them to do it for you.
Some knife shops also offer sharpening services.
I sharpen our serrated knives with a special curved / tapered ceramic sharpener. It will even do fairly fine serrations, but it won’t sharpen “micro-serrated” knives like Henckels, and I’m not sure that any sharpener will.
Not so hard, actually; I use one of one of these for sharpening the few serrated and comboedge knives I have. It usually takes me only a couple of minutes to put a viciously sharp edge back on them.
It is something of a myth that serrated knives need less sharpening, or (as the serrated looney people say) “You never have to sharpen them!” (Actually, it’s true for Cutco; once you’ve worn the edge off, it is so pointless to put an edge on the shitty, soft low-carbon stainless they use that there really isn’t much of a point.) The reason serrated knives cut so well is that because the functioning edge is dished you end up applying more force to a smaller edge area. The tradeoff is that you are doing more sawing than cutting, and once the edge wears off it is impossible to make fine cuts with the edge, or to use it for shaving onions and garlic properly. (I actually got so fed up with the Cutco knives that a friend owns that I bought her a proper Wusthof santoku so that I can cut and slice vegetables when prepping or cooking at her place.)
This is not to say that serrated knives don’t have their place; when it comes to cutting through thick cardboard or cutting thick manila or hemp line a serrated edge is a godsend, since the abrasive cardboard and natural fibers wear an edge quickly and the sawing motion and resulting unclean edge is no detriment in those cases. However, for most uses, and particularly culinary applications, I would much prefer a standard edge, both for the cleanness of cut it provides and the ease with which it can be maintained at shaving sharpness with a flat diamond hone.
Those “micro-serrated” blades should be considered disposable; fortunately, the steel used to make them is usually of a grade that isn’t worth sharpening anyway.
Stranger
I touch up our serrated steak knives with a regular sharpening steel. Usually one or two passes on each side drawing the cutting edge into the steel with a light touch, and a couple on each side drawing away from it. Not the same as actually sharpening a dull blade, but so far it’s worked nicely at keeping them performing well.
Spyderco makes a sharpener that works extremely well on all kinds of cutting tools, including serrated knives. I’ve owned one for nearly 20 years and can’t recommend it highly enough.
Awesome; I have a new tool. That looks like one of those things you think can’t possibly work as well as they claim, but since you’ve endorsed it, as it were, I’ll give it a go. Thanks!
Make sure I count my fingers when I’m done.
This is what I use. It will give a razor sharp polished edge to just about anything.