Thread: To Lap a New Hone...

I lapped my Shaptons right out of the box using the grid pattern. I had read it was a good idea to do so, so thats what I did...!

Now I only lap them to clean off the swarf, or if I have done a lot of honing and I want to ensure that the stone is flat.

Place a ruler on the 2 diagonals of the hone and use some light, if the light passes to the other side it needs to be lapped. (make sure the ruler is straight, I know for experience not all are )

I used my naniwa 8k out of the box with no problem, the 5k needed lapping

How can you guys use a Naniwa SuperStone OTB with residual sticker glue on the surface?

I know first hand that these stones will act better when lapped a few times too. The Naniwa Choseras are the same way, in fact the Naniwa Chosera barely work at all until lapped.

Flatness is only one reason to lap a stone.

Another thing worth noting is that the edges of stones should be rounded after flattening has been done. If you don't do this your razor will be elevated by the high corners and not be allowed to make full contact across the bevel. In the knife sharpening world we call this "sharpening on rails".

Originally Posted by DaveMartell

How can you guys use a Naniwa SuperStone OTB with residual sticker glue on the surface?

I know first hand that these stones will act better when lapped a few times too. The Naniwa Choseras are the same way, in fact the Naniwa Chosera barely work at all until lapped.

Flatness is only one reason to lap a stone.

Another thing worth noting is that the edges of stones should be rounded after flattening has been done. If you don't do this your razor will be elevated by the high corners and not be allowed to make full contact across the bevel. In the knife sharpening world we call this "sharpening on rails".

I bought mine from Fine Tools in Germany and got the 20mm thick superstones with no base so my honing surface is the opposite side from the sticker. Lapped them anyway as it makes no sense to me not to. I also routinely round all edges. IME if I take a Shapton Pro or a Naniwa superstone out of the cabinet that was lapped the day before ....and throw a pencil grid on it will not be absolutely flat the following day. Some will be close and others further away but I lap mine every time I use them.

I use a pencil grid initially and as I am working with a stone I lap the swarf away without the grid using the method of judging by color. Whether all of this is necessary is debatable but it is what I do because it makes me feel good.

I would at least check for flatness as yoshida said, and if necessary lap it as Jimmy advises.

Originally Posted by DaveMartell

How can you guys use a Naniwa SuperStone OTB with residual sticker glue on the surface?

Well, I peeled off the sticker, added some water, and ran the razor over the surface of the hone using a normal honing stroke.

Another thing worth noting is that the edges of stones should be rounded after flattening has been done. If you don't do this your razor will be elevated by the high corners and not be allowed to make full contact across the bevel. In the knife sharpening world we call this "sharpening on rails".

This makes no sense to me. If you lap the entire surface of the stone, the edges will be at the same height as the middle. "High corners" means that the hone has not been properly lapped.

Please don't hold me to this. But, I believe I remember Lynn Abrams saying he lapped the Naniwa Superstones when received. But, again if I remember correctly, the reason was that he thought the consistency of the "stone" at the top of the hone was not consistent with the rest of the hone. He had to lap thru the thin layer to get to the regular consistency.

But, heck! It might have been anyone who said that...

Whoever said it, it makes sense to anyone who has poured concrete. Gravity pulls particles downward before the concrete sets. But, I wander...

If true, I doubt it would be very critical.

Originally Posted by holli4pirating

This makes no sense to me. If you lap the entire surface of the stone, the edges will be at the same height as the middle. "High corners" means that the hone has not been properly lapped.

Check your flattened stone by running your finger/thumb from the middle of the stone out and over the edge and you'll feel the high edges. When you sharpen a knife on a stone that hasn't been rounded on the edges the stone will only show black streaks on these high edges - nothing in the middle. This means that you are only providing 1/4" of stone surface to the knife when you should be providing the near full width of the stone. This isn't something that's easily seen or apparent when razor honing since razors don't bridge across the width of the stone the same way that knife does, however, on thin width stones (sometimes used) and in certain techniques the edges of the stones are coming into play more than others. I can't tell you how many times I've seen people proclaim their dislike of a stone that they had high edges on only to fall in love with the stone later on when the edges were rounded for them. The reason for this is that they are using more surface area of the stone after the edges have been rounded. The question is then often asked about why they don't notice this on other stones that they lap the same way and love? My answer is that some stones cut faster than others and the small amount of contact area presented by some stones doesn't matter where it matters very much on others.

Correct me if I'm wrong here - after you lap a hone, the top surface is flat. On a flat surface, all points lie in the same plane. Therefore, the sides of the hone are at the same height as the middle of the hone.

I don't know what you mean by "bridge," but I have hones that are narrower than a razor and hones that are wider than a razor, and I've never had any issues with a razor only contacting the edges of a hone on any lapped hone. I cannot imagine why a knife with a straight or smiling edge would act any different than a razor with a straigth or smiling edge, but I don't hone knives, so I'll take your word that there is a difference. Knives may indeed need rounded edges, but razors do not. The only reason, based on my experience, to round the edges of a hone is so that you don't accidentally dig the edge of your razor into a sharp edge and damage the edge.