Thread: Norton 4K/8K first lapping

I just did the first lapping on my new Norton 4K/8K. It wasn't even close to being flat. I had to lap 1/16" to 3/32" of material off before I got it perfectly flat on the 4K side. Same on the 8K side. It took hours to lap this thing and I didn't even finish the 8K side. I still have two opposing corners that are still rough but I got tired of lapping it. Enough to hone my razor though as long as I stayed away from those corners. I used a DMT Duo Sharp with the coarse side rated at 325. The one that's perforated with the plastic in the middle. Also tried 325 wet/dry sandpaper on granite.

Is this normal for a first lapping? Should I get a different lapping hone? Does anyone use the Norton lapping stone? To me it seems they could have gotten it a lot closer to flat than that. The stone actually rocked back and forth on the diamond plate!

Anyway, I honed my razor using pyramid method and then a few laps on CrOx on felt paddle and shaved with it. Got a good shave from it. I was impressed by the polish the 8K left on it. It leaves more of a mirror finish than the PHIG I got from Woodcraft. The PHIG leaves more of a satin finish.

Should I get the Naniwa 12K? Will I notice a difference in smoothness of shave?

Sorry your initial lapping took so long. I'm not sure what to say about that. I would highly recommend the Nani 12K. It will turn a good shave into a great shave. I threw my PHIG in the trash.

You can get a Naniwa to polish up past the 8K if you want, but you don't have to. Totally up to you. I like mine

I had to lap my 4/8 Norton quite a bit on both sides too. Not quite as bad as yours it seems. I have read that us Str8 razor peeps are the only ones that need them perfectly flat. We are a small portion of the market, the knife guys are fine with them as they come out of the box.

I got a Norton 1k/8k combo a couple years back to sharpen my hand plane blades and think I remember having to lap it quite a bit with the same Duo Sharp (I don't think it's the DMT). I lap my Norton before and after I use it, but it stays very flat. I used the same Duo Sharp for a couple years until it wore out then I got a DMT 325 and like it better because it's heavier; however, if you lap it in random circles or figure 8's instead of just back and forth then I both will work just fine to keep your stones flat, in my experience.

I got the Naniwa set (3, 5, 8, 12) for my razors and use my 1/8k Norton for bevel setting. I love the Naniwa 12k and certainly don't believe I'm able to get the most out of it and I feel like I get really sharp, smooth shaves out of the Naniwa 12k then 7 laps on CrO3 on a strop or .50 diamond on felt then leather. I practice on 3 of my 4 razors every day using different stones, slurries and finishing techniques and when I want to "zero-out" my razor and feel what a sharp, smooth shave feels like on that razor for reference, I finish it on the Naniwa 12k, CrO3 or .50 diamond and strop. When I am trying to practice finishing, I try to finish a razor on my Naniwa 8k to feel like my 12k. I haven't touched my C12k since I got the Naniwa.

Hope this helps.

The dmt325 is a little slow for initial lapping IMO. It will do very well for subsequent lappings and leaves a smooth surface, ready for honing.

When I get a new stone I start on the norton lapping plate. It's very fast and channels away swarf. Then I grid-lap again using the dmt for a nice smooth surface.

Michael

I had a similar situation when lapping my Norton 4K/8K for the first time too. I also used the DMT 325 for lapping, and still do for all of my stones. Nowadays, when I sharpen razors I do a quick lap of each stone. My 8K still has a corner with a rough edge, but I stay away from it.

After reading various posts over the last month, I'm considering getting a Naniwa 12K as a finisher. That should smooth the edge from the 8K.

I'll probably get the Naniwa 12K since it gets so much praise here as a good finisher. The edge did feel really sharp but maybe a tad harsh for my face off the 8K.

My diamond plate has seen a lot of use setting bevels on hand planes and chisels so it is probably getting pretty worn. Wish I'd gotten the Norton lapping plate before I started. I may get it anyway with the Naniwa 12K. Or I see that Naniwa has a lapping plate that's less expensive!

I lapped a Norton the other day. The 4k was easy ~ the 8k took 20 mins on a 140 grit Atoma.
That seemed a long time.

Yeah, my diamond plate was pretty worn but I didn't want to wait to hone my razor. A couple hours is a pretty long time to lap😄