Thread: To Lap a New Hone...

Does everyone know that you need to lap/flatten a new hone right out of the box before use?

I've read a lot on razor forums where people use stones right out of the box without lapping them first. I've seen it in pictures and noted many making comments about this. I also know from talking to my customers and knife sharpeners that they too do this as well. It seems like this bit of information has been lost or never known, I can't say which but that doesn't matter.

The fact is that a Japanese synthetic waterstone comes with a sort of surface crust that needs to be broken through and lapped away. Not to mention that many aren't flat and lots have ink and even stickers on the surface that need to be dealt with. If you don't break through the surface of some stones they actually won't work almost at all. I've seen it countless times where a sharpener buys a new set of pricey stones just to be left scratching his head after the first use pondering how these things could be so highly regarded when he can't get them to do anything decent for him. He then thinks that either the stones suck, the people who gave the advice on the stones are idiots, or he doesn't know what he's doing -all very frustrating things to deal with.

I have found that there are some exceptions to this rule but they're few and far between so when you get a hone lap it and all will be good.

Remember, I'm talking about Japanese synthetics, not naturals or any other nation's sharpening stones, they may well all be different in this sense.

Dave

I respectfully disagree. I recently bought Naniwa 5 and 8k hones. I used both right out of the box, without lapping, and honed up a batch of 16 razors. They all came out great. Lapping out of the box, though probably a good idea, is not necessarily necessary. As with all things, there must be a percentage of hones that are flat or close enough to flat to use straight away, and others that are not.

I always lap a new hone regardless of origin. I feel better doing that and in the scheme of things it is doing no harm and maybe a lot of good.

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.