View Full Version : Lapping the Norton Stones
08-28-2007, 10:46 AM
Recently I picked up two new Nortons, a 4K and an 8K. I figured that doing a pyramid would be easier if I didn't have to keep cleaning and flipping the combination stone that I have. With the two new stones I also purchased the Norton flattening stone. Out of curiosity, I decided to try the flattener on the two new stones before using them. After penciling in the cross-hatch pattern on both sides of each stone, I started lapping. Surprise!! Neither stone was even close to flat. After some work, all the pencil lines dissappeared. Now for the test. Did a pyramid with a Henckels Friodur (5/5, 3/3, 1/3, 1/5, 5/20), then finished on a pasted paddle. Stropped 60 round trips on the leather - and boom! Passed the HHT all along the blade! By the way, I also got a great shave.
Just because a stone is new, don't assume that it is flat. In this case, it could have lead to a lot of frustration. My combination stone was much closer to flat than the two separate ones, but still needed a little touch-up.
Flattening can't be overemphasized, even on brand spanking new stones. Shaptons are pretty flat out of the box, but I hate that they need special lapping plates. That, combined with their hard feel and poor feedback, push them lower on my list of great stones.
08-28-2007, 01:05 PM
Flattening can't be overemphasized, even on brand spanking new stones...
I only use the flat part if the edge is exactly straight, which is not the case with many of mine and those I hone for others.
08-28-2007, 06:40 PM
I bought one of those Norton flattening stones and didn't like the job it did on my hones. I had to go back and correct them with my tried and true 12"/12" tile I got from home depot and my 80, 220, 400 grit wet dry paper. The flattening stone seemed to create a dome on the hones. It could be me.
08-28-2007, 07:28 PM
Just because nobody else has said it - Nortons also need to be re-lapped fairly often (depending on use) You cannot assume it's flat just because you lapped it soon, especially if you used pressure to hone out a chip or something
I've gotten in the habit of lapping my stones every time I use them. Takes only seconds, and don't forget to bevel the edges.
08-29-2007, 06:19 AM
Your comments have been noted. I have a 12 x 12 piece of thick glass which can be used if the Norton flattening stone no longer does the job.
08-29-2007, 03:05 PM
Yup I use a piece of glass too. I popped in to my local glaziers and bought a roughly 10" x 6" square of 6mm thick toughened glass which is perfect for lapping on, they smootheed the edges for me too on a machine they had there. :smile:
09-06-2007, 11:29 AM
I found that my Norton lapping stone needed to be lapped, thus the bad results. I laid out a grid with a Sharpie. The stone was high on the ends right out of the box. I used 4 sheets of 120 wet dry on a ceramic tile. Finally got it flat.
I guess I should have checked. Who would think.
09-06-2007, 11:41 AM
I lap my stones with a DMT continuous stone (325). I like using it more than the Norton lapping stone, but you have to be mindful of the swarf. I lap the stones under running water. Even if they're flat, I lapping refreshes the surface and will affect the amount of metal being removed during honing.
A nagura stone works just as well for refreshing the surface of the stone during sharpening. There are various schools of thought as to how much swarf should be removed, but the more anal among us like to keep the stones clean. I know I do, and the nagura can't be beat for that.
11-16-2007, 12:21 PM
I try to flatten mine before every use. Doesn't take very long and makes a big difference.
11-17-2007, 07:02 PM
I was wondering how do you know the flattening stone is flat? Is there some kind of test that you do to check it?
I can sell you a flattening stone flattener for a good price.
11-17-2007, 08:02 PM
:cool: Cool, I'll have you ship it to my future home site on that swamp land I bought last week. :wink:
Sometime down the road, you'll also need a flattener for your flattening stone flattener.
That's why I like the DMT plates for flattening- they're heavy nickel plates that have been machined flat.
11-18-2007, 07:22 AM
+1 on the DMT plates!
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