Thread: Lapping a Norton 4k/8k

Gents,
I'm just about to purchase my first wetstone, the Norton 4k/8k combo stone, but have read here (and elsewhere) that the stone should be lapped before use to ensure a flat surface since the Norton's aren't usually perfectly true to start with.

I don't really fancy buying the $30 flattening stone, although I will if needs must, but I am really looking for a less expensive alternative. I've heard something about using a piece of plexi-glass and high-grit wet sandpaper, but can't for the life of me figure out how you would do this? Hold the sandpaper to the plexi like a sanding block? Glue the sandpaper to the plexi and run the Norton over the plexi?

Can someone please explain to me the best (inexpensive) way to lap a Norton? Details are certainly welcomed for this newbie!

Thanks,

Mark

Hi Milton,
Just use some electrical tape to hold the sandpaper down on the glass and rub until flat. To be sure you have it thoroughly flattened, draw a light figure eight on the surface of the Norton and then take a couple of passes on the sandpaper. If it's flat the 8 will disappear evenly. Then most guys will round off any pointed corners on the surface of the stone. Others may add some other points to this post, as I am not the Honemeister Deluxe. Good luck!

I use a spare piece of granite countertop and 600 grit wet/dry sandpaper. Wet both surfaces. Draw some pencil lines on the hone( I use several large big X's from corner to corner and edge to edge). I then use a short circular motion until all of the pencil lines dissappear. The hone will want to stick to the paper when its flat. On both the 4K and 8K sides it doesn't take much time ( a few minutes).

Originally Posted by Firebox

I use a spare piece of granite countertop and 600 grit wet/dry sandpaper. Wet both surfaces. Draw some pencil lines on the hone( I use several large big X's from corner to corner and edge to edge). I then use a short circular motion until all of the pencil lines dissappear. The hone will want to stick to the paper when its flat. On both the 4K and 8K sides it doesn't take much time ( a few minutes).

That exact process worked for me.

Use a piece of plate glass. Wet a sheet of 400 grit (wet or dry) sandpaper. Wet the glass which rests on several wet sheets of newspaper on a counter top. Lay the wet sheet of 400 grit (grit up) on the glass. Wet the hone well and use an 8 pattern on the 400 grit. Then switch to 600 grit and repeat on both sides. Hold each side on all four edges at about 70 degrees and drag each edge to finish off the edges.

Monte

I find 800 grit to be a good finish for my Norton, perhaps the best.

X

Mark,
Flat is a relative term and not an absolute. In industry you have to specify the flatness. When sharpening razors though, the flatness on any stone that can be achieved by lapping on a DMT Coarse continuous diamond hone is "flat enough". At $55 they're almost double the cost of a Norton flattening stone BUT and this is big, you get a lifetime tool that will sharpen ANYTHING in addition to lapping waterstones. They never dish and they last forever. I've been lapping coticules for 5 years on the same stone and I always test with a machinist's straight edge before and after lapping.

Norton stones are usually flat enough to hone razors right off the bat BUT the surface is greatly improved by lapping. Why? These are vitrified, or baked, stones. The immediate surface is different from what is just under it. You can let the stone "break in" gradually over time or you can lap it.

I have talked with folks who have used sandpaper on glass, lapping grit on surface plates, etc. but eventually they come to the realization that, for consistent results, you want a high quality tool. That's why I use and carry DMT stones.

Thanks for the great pointers guys! I had no idea lapping a stone was this involved or had so many variations in technique or tools!

I think this is why this forum is so important to all of us, new and old - it is the perfect venue to gain information and exchange ideas.

Thanks again, and now I have to go rethinking my choice in lapping apparatus!

Mark