Thread: Lapping A New Norton 4k/8k

When I started (and I'm still new to it) I didn't know this but I'll pass it along. You will want to lap the hell out it for more than just ensuring that its flat. You're also smoothing out the stone. I didn't know this at the time but you're supposed to try to strip off about 1/8 of an inch of the 4k side until it feels smooth. The Norton 4k comes fairly gritty and it needs to be lapped to smooth out the surface. If you don't, you won't be able to polish the edge at all.

Originally Posted by OCDshaver

When I started (and I'm still new to it) I didn't know this but I'll pass it along. You will want to lap the hell out it for more than just ensuring that its flat. You're also smoothing out the stone. I didn't know this at the time but you're supposed to try to strip off about 1/8 of an inch of the 4k side until it feels smooth. The Norton 4k comes fairly gritty and it needs to be lapped to smooth out the surface. If you don't, you won't be able to polish the edge at all.

1/8 of an inch ??
Sounds like a bit much to lap off of a new Norton, but I could be wrong.

It took me about 10 minutes of easy lapping with a 325 to bring mine into play.

The 8K may take a little more lapping than some stones, but lapping off an 1/8 of an inch is excessive and unnecessary. I've had mine for almost two years now, have lapped it a bunch of times and doubt I have taken that much off it yet. It works just fine.

Well I definitely appreciate the advice! I actually went ahead and ordered a Norton Flattening Stone which will hopefully get me going in the right direction, but if a DMT325 is what you recommend then I will probably go that route as well. As I said I am just starting out, but my goal is to hopefully build a collection of nice straights that I have honed myself. Gotta start somewhere, though!

Thx again for the replies!

For those of you that didnt have to lap much off the 4K side of your Norton.....congratulations, you have been fortunate. My Norton needed to have about an eighth of an inch lapped off the 4K before it was smooth enough. Mine had quite a bit of porosity and texture in the outer most layer.

I guess the right answer is "keep lapping until the surface is smooth and free from roughness, and don't be surprised if you have to take off quite a bit".

BTW, the DMT 325 is a really good choice for a lapping stone. I have the Norton lapping stone, a DMT, sandpaper and a Shapton DGLP. The DMT is probably the sweet spot in the group. The Shapton is better, but there are definitely diminishing returns at its price point.

Edit: One more thing, don't forget to put a small radius on the edges of the stone after you lap it.

How bad do you think the norton lapping stone is? I have been using the Norton Lapping Stone (and only that one) since i got the kit a few years back, but haven't tried anything else; I *think* it's been giving me good results, but don't have anything to compare it to.

Originally Posted by jamesm

How bad do you think the norton lapping stone is? I have been using the Norton Lapping Stone (and only that one) since i got the kit a few years back, but haven't tried anything else; I *think* it's been giving me good results, but don't have anything to compare it to.

Personally, I think it is junk. The reason is that it is very soft. Much softer than othe rnorton stones. So any mistakes during use will dish it out.
Given the small difference in price, I'd buy a DMT325 grit diamond plate. That will stay flat, and last a lifetime. The norton lapping plate is ok for using, but you have to chck regularly whether it is still flat or not.

Originally Posted by Hirlau

1/8 of an inch ??
Sounds like a bit much to lap off of a new Norton, but I could be wrong.

It took me about 10 minutes of easy lapping with a 325 to bring mine into play.

I didn't exactly measure it and maybe exaggerated some. The point being, it seemed that I lapped away a lot more than I thought would ever be necessary with a brand new stone. I bought a Naniwai 1k at the same time and couldn't figure out why the 4k felt so much more rough than the 1k. I hadn't smoothed it out yet. My honing mentor here, Stefan, told me to get busy with the DMT and not to be afraid to strip some of the 4k off. Then things started to make sense.

Yes, I can see there being a difference from Norton to Norton, nothing is made "Exactly" alike. Just when I saw the 1/8 of an inch reference, I actually took a ruler to my Norton & said, "Holy Cow!".

I'm glad you got her up & running, though.

Originally Posted by Hirlau

Yes, I can see there being a difference from Norton to Norton, nothing is made "Exactly" alike. Just when I saw the 1/8 of an inch reference, I actually took a ruler to my Norton & said, "Holy Cow!".

I'm glad you got her up & running, though.

My reaction was the same when I was told how much to peel off of it. So much to learn. But with each discovery I know we're preserving what was almost lost knowledge. It's important that someone keeps these traditions alive. I guess that is our charge.