Thread: Lapping Question

Besides the flatness issue/non-issue Naniwa's and Nortons have a top layer that just needs to be removed before they start honing their best.. I didn't notice this on my Shapton's but it has been some time since I bought those..
At the Denver meet John brought a new set of Norton's and most of the new guys were amazed at just how much lapping was required to get the 4k/8k flat and that top layer gone...
On the Naniwa's also watch that spot where the sticker was, if you can still see that spot clearly, keep lapping and as noted above WATER is your friend...

Amen to that in regards to the Nani's...

Originally Posted by gssixgun

...a new set of Norton's and most of the new guys were amazed at just how much lapping was required to get the 4k/8k flat and that top layer gone...

Speaking of that, is there sort of a red-herring layer, or a "grey zone" in between a new Norton out of the box and a completely lapped one?

I spent a few hours lapping mine flat and the surfaces feel just the way that everyone describes how they should feel (smooth on 4k, silky smooth on 8k), but I see everyone talking about having to lop off as much as an 8th of an inch, and I took off less than a 64th from each side. Never noticed any grittiness below the original surface.

Did I just get lucky?

Originally Posted by Goggles

Speaking of that, is there sort of a red-herring layer, or a "grey zone" in between a new Norton out of the box and a completely lapped one?

I spent a few hours lapping mine flat and the surfaces feel just the way that everyone describes how they should feel (smooth on 4k, silky smooth on 8k), but I see everyone talking about having to lop off as much as an 8th of an inch, and I took off less than a 64th from each side. Never noticed any grittiness below the original surface.

Did I just get lucky?

There are differences, in the Nortons when it comes to lapping them in. I would like to say that it coincides with where they are made, (USA, Italy, Mexico) but I can't say that for sure, it is just my thoughts about it...But yes some take much longer, some are easy as can be...

Well I got the exact same set... and while I never posted about my lapping them I too spent about an hour lapping them.

Curious if you notice that while lapping them you got like a suction action going on with yours?

Yep, and it took quite a bit of elbow grease to pry them apart, lol!

Originally Posted by Earthdawn

Well I got the exact same set... and while I never posted about my lapping them I too spent about an hour lapping them.

Curious if you notice that while lapping them you got like a suction action going on with yours?

if you get enough slurry between your stone and the lapping media it will create suction. Same effect will occur when you have two fine grit surfaces rubbing against each other, it is caused by surface tension.

Originally Posted by mainaman

if you get enough slurry between your stone and the lapping media it will create suction. Same effect will occur when you have two fine grit surfaces rubbing against each other, it is caused by surface tension.

I assume that theres a little more slurry being created when lapping new stones?

Thanks for the info.

Originally Posted by Earthdawn

I assume that theres a little more slurry being created when lapping new stones?

Thanks for the info.

I think it is all the same if the stone is new or not.

Once you get two extremely flat surfaces, you'll feel suction between them even when they're dry. I don't know how this works, exactly. I put a hone down on a table last week and had to lift a little harder than the hone's weight to pick it back up.