Does a Norton need lapping?

Hi all,

I was just woundering if a Norton Waterstone needs lapping when it is bought new.

I have had mine for about a month now (I have a 4/8K), and I have notices that I cannot hone any of my razors right with it. Yesterday I notices that when I hone on the 8K side, I get a noice from it that makes me think that it is not completly smooth, and I also get some black lines one it (not sure how).

If it does have to be lapped before use, can I use sandpaper to lap it, or do I need to buy a lapping stone?

Cheers,

Steven

Steven, look through some of the older threads and you'll find the answers to all of your questions. In the interests of expedience:
1) Yes it does need to be lapped
2) Draw a 3x5 grid on both sides (with a pencil), place some wet-dry 600-1000 grit sandpaper on a glass/marble/granite plate and do figure-8 movement until the pencil marks disappear, flip the hone and do the same on the 4k side. The hone also has to be soaked and if you feel the surface of the sandpaper being dry you can always pour a bit of water over it.
3) You don't NEED it but it may make your job easier.

The black lines are just the metal that the hone removed from your blade but if it hasn't been lapped, the removal will be uneven and you'll never get a shave-ready blade.

Quote:

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Originally Posted by nerobot

If it does have to be lapped before use, can I use sandpaper to lap it, or do I need to buy a lapping stone?

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I have used a couple of stones so far, and none of them was flat, even when the appeared to be perfectly flat to the naked eye.

What I do (as tought to me on this forum) is to draw a grid on the stone in pencil.
Then lay a piece of 1000 grit sandpaper (for wet sanding) on a very flat surface (like a glass plate or ceramic or granite tile).

Wet the paper, and rub the stone over the paper in a figure 8 motion.
every few laps check if the lines are still there.
When they are gone, your stone should be flat.

The places where the lines disappear first are where the stone was thicker than the other places.

If you have to rub a lot before the lines are gone, you might want to do this a second time just to make sure. I had to do 3 times.
The reason is that the lines are also slowly erased by the water and loose grit.

Afterwards, if you want to check if your stone is still flat, do this test again. the lines should all be gone at the same time after 1 or 2 laps.