Lapping New Nortons

[DJKELLY]

I read somewhere, probably here way back when, that one of the downsides of the synthetics was having to soak them and lapping a new one before it would cut correctly and not just to get it flat, but to get down to good surface. Is that correct and how far down? I use a coarse DMT for lapping, but have a surface plate and good w/d paper if that is a better solution. I have some old synthetics that work fine, but the new ones don't. I have heard that the new ones coming from Mexico or something and are not as good. Any help would be appreciated. Later, Denny

 

[rayman]

Dennis,
I am familiar with what you are asking. Yes, you have read somewhere that up to 1/8" needs to be removed from the Norton stones before they produce expected results. My personal experience with the Norton required nearly 1/16" removal before it started working as expected. So, yes it is true about the removal on a Norton, but remember YMMV....Smile

Norton synthetic stones need to be soaked before use, but Naniwa and Shapton do not need soaked. The Naniwa stones also need to be lapped to get to the good honing surface, but not very much. Their are several of the Naniwa stones that require constant water application, since the water moves through them quite fast and their grit sizing doesn't seem to match their stated size.

Shapton Glass on the other hand are the most consistent synthetic stones I have used. They do need to be lapped, but only to re-flatten the surface. Their grit sizing seems to be exactly as stated, they are fast cutting and you can get very nice synthetic edges from them time after time. The edge produced off the Shaptons is very crisp and I believe the exact opposite feel of the Coticule, but it seems to be the most reliable in producing an edge that many individuals prefer over the softer and smoother Coticule as well.



Ray

 

[DJKELLY]

Thanks, pal. That is a lot of lapping. Think I will go to the granite surface plate for that. I knew something had to be wrong. Later, Denny

 

[Rosco]

My Norton 4k felt gritty 'n' shitty until I lapped ablout an 8th of an inch off it upon the advice of the very Norton knowlegable Mr Abrahms. My 8k always felt nice to use, and I still like it. After lapping the 4k felt much better to use and produced better results. I still don't like the feel of it, but I now believe this to be a personal issue. Before lapping, something definately didn't feel right, even in my untrained hands.

 

[DG7]

I have new Norton stones (bought in the last couple of months), the 220/1K and 4K/8K combos. The 220/1K was made in Mexico, the 4K side in Italy, and the 8K side in the US. I think you'll know when you're done lapping, especially with the 4K/8K. The whole surface will be really quite smooth.

One thing I've noticed, is that if I mark the stone with a pencil, and then go to wet/dry paper on a flat granite surface plate (made for sharpening, etc.), the pencil marks will be removed fairly quickly, but the stone will not be flat enough or sufficiently lapped. If I go straight from the sand paper, remark the stone with pencil, and start lapping with a DMT, I'll notice right away that the stone isn't flat. It seems like, at least from my experience, the sand paper is removing the pencil marks before it's perfectly flat, while the DMT will only remove the pencil marks when it's really flat. I was lapping my new Les Lats from Ardennes last night, and figuring it's such a hard stone (especially the creamy side), I started off on some wet/dry paper at first. I didn't want to smooth out my DMT right away. I was surprised at how quickly the pencil marks were removed, but it was very obvious once I put it on my DMT that it wasn't flat. It took quite a bit of work, but I knew I was done when the pencil marks were gone from the DMT.

I'm not sure how much I had to take off when I was lapping my Nortons, but for me, progress was really quite noticeable because the whole surface was really smooth except for one corner which looked ok, but felt kind of rough. Again, I had started off with wet/dry paper and all the pencil marks were gone, but that one corner just didn't feel right until I flattened it with my DMT. I haven't had problems with either stone (quality wise), though I tend to use the 220/1K combo more for repair work now, and my coticules for the rest.

If you do use the granite surface plate, just be sure the whole side is pretty smooth, especially on the 1K, 4K or 8K sides. The whole side should have a uniform feeling when honing a razor, and then you'll know it's done. Otherwise, it will be really gritty on areas that aren't quite flat. If you've got the DMT, I'd say do most of the work on the wet/dry paper until it all feels pretty smooth, then finish it off with the DMT so you know it's absolutely flat. Then, if you want to use finer wet/dry paper, you can go back to the surface plate. The little instruction booklet that comes with the Nortons says what kind of grit to use. I don't have that in front of me, but it seems like it suggested the 4K/8K sides should be finished with somewhere around 400-600 grit.

 

[DJKELLY]

Interesting about the lack of flatness off surface plate. I think it is easy for the paper to bunch up, even when stuck down with water tension. Thanks. Denny

 

[Disburden]

Yes, Norton stones need to be soaked before lapping for a half hour and then lapped 1/8 to be used, especially for the white 4K side of the hone. Naniwa stones don't need to be soaked but need to be cleaned prior to each honing which only takes a few minutes. Some people love the Shapton Glass stones, I dislike the edges from these hones a lot, they are hell on my face and I sold mine off because of it.

When lapping the Norton 4/8k I always recommend going through 4-5 pencil grid sessions before using the 4K side.