Thread: just how flat is flat?

so i sharpened up one of my kitchen knives on my norton. don't ask.

the thing is, i've created some inconsistencies in the surface of the hone, specifically, a long arc where i was drawing the knife away from myself. i figured it would happen this way, and i wasn't too upset about it since i knew i'd have to learn how to lap the stone eventually, but just flat does it have to be? do i really have to lap it since i can only barely feel the difference? i'm guessing the answer is yes, but i figured i'd ask anyway.

also, just for the hell of asking, i figure i might as well try to sharpen up my gerber stainless steel pocket knife before i lap the norton. i know lots of the folks on this site are experts on all kinds of sharpening (not just razors), so does anyone care to offer any advice on sharpening a knife? any help would be appreciated. i got the kitchen knife sharpened up a bit, but who knows how bad my technique might be--that thing was so dull you couldn't cut tomatoes with it. literally. actually, the same goes for my gerber.

Hi,

the hone has to be perfectly flat to be really suitable for a str8. This can be checked quite easily by taking a glass plate and holding the wet stone to it while checking from the other side. It should keep an even and flat contact over the whole surface area, any irregularities will show.

If you ask for my opinion, I would recommend to use the hone for razors only and nothing else. Its easier to maintain the razors-only hone and as you described kitchen knives etc. leave markings on the stone.

When you spent your first days honing a razor without success and then finding that its due to some self-caused surface problems of the hone you will easily find a way to justify the expense for the extra hone anyway

Just my 2 cents,
-Axel-

Like they say sharp is sharp and flat is flat. There may be some argument on the how sharp is sharp question but there is no argument on how flat is flat. If there is any deviation on the hone you will never be able to properly hone your razor. The glass plate is a good test or you could invest in a flattening plate. I have a shapton and I'm glad I made the investment because it makes flattening a real pleasure.

As far as your knives go I agree you shouldn't mix knives and straights on the same hone. I find the big problem with sharpening knives is maintaining the proper angle consistantly and knowing the proper angle depending on the type of knife. Some guys have a real steady hand and are masters at it. For the rest of us the various sharpening kits take the guess work out of it. I have a diamond set which works fast and flawlessly

i guess you guys are right. i just lapped it anyway. someone on here suggested getting a faux marble tile and i swear i could kiss him for it--for fifty cents at lowe's i got a flat plate, and the guy there even cut it down a bit for me. that, and five sheets of 600 paper only cost three bucks and change. long story short, the setup worked wonders and the stone is flat and smooth as you please. thanks for the advice, guys.

The next time you lap your hone use a pencil and draw some lines on the hone. Then lap until all of the lines are gone. That is the best way I have found yet. Using the glass plate and suction test is not as good.

Originally Posted by cyrano138

i guess you guys are right. i just lapped it anyway. someone on here suggested getting a faux marble tile and i swear i could kiss him for it--for fifty cents at lowe's i got a flat plate, and the guy there even cut it down a bit for me. that, and five sheets of 600 paper only cost three bucks and change. long story short, the setup worked wonders and the stone is flat and smooth as you please. thanks for the advice, guys.

I ain't lettin' no guy kiss ME! Now if you were a lady, we might talk.

That little faux marble tile idea is really good, and really cheap. I originally figured that out when I was hunting something to lap the hones I used for chisels and plane irons on. It was cheaper than buying a piece of 1/4"plate glass, and I tested it with a machinists straight edge and it was incredibly flat for the price. Something like +/- .003". I was amazed!!

I'm just glad you found it useful.

A side note on your Gerber and kitchen knives...

The Gerbers, I have found to be a harder steel than most other pocket knives. What I find that works really well for me is the little light grey ceramic Lansky multihone (aka dogbone). It's about 4 inches long and has a triangular crossection. It keeps the knives sharp for normal knife use, is fast, and no mess.
I use a white plastic eraser to keep it clean (staedler-Mars drafting).

My family is terrible with kitchen knives. I have a set of sabatier knives that they routinely beat the snot out of the edges with. I'm trying to teach my daughters how to take care of a nice edge -- given up on trying to train my wife. The girls are showing promise . I keep the Lansky in a kitchen drawer and it works great to quickly bring back a decent edge.

Thanks for the tip on the faux marble tile. I'm going to look for one of those. I've been using a real marble slab that was for in the kitchen rolling dough on. Don't know for sure how flat it is. I only use the Norton flattening stone now on my Norton.

When I first recieved my norton I tried the water-glass trick and it seemed to be quite flat. Flat enough to hold to the glass through the suction of the water. So I proceeded to hone up a razor on it, seemed to work alright, I got the razor to pass the HHT, and honing felt alright. Then I lapped it. Used the pencil trick randy mentioned, which, worked great. Honing after that was much better. The results weren't leaps and bounds passed before, but honing was certainly was much smoother and easier.

As far as knives go, I too have a lansky sharpening product. I have the standard sharpning kit. I think they're around $20USD, but I'm not sure, I recieved mine as a gift. It comes with the angle guides (which are virtually foolproof), but I don't use them. I really like it, except for the fact that the stones use oil as a lubricant; so it's a bit messier than water. I also have a gerber pocket knife, and the lansky's work quite nicely on them and pretty much any other knife I've used them on.

As of yet my norton 4k/8k hasn't touched any of my knives. The highest grit I find I've ever needed for any of my knives is 1000 grit (for which I have a small japanese waterstone). However, it is not uncommon for me to just stop at the lansky "fine" stone which is rated at about 600 grit.