Thread: How much time/effort should it take to lap a Norton 4k/8k

I've had a Norton 4k/8k hone for about a month now, working out the basics of honing. For practice, I've been using a few decent german blades picked up at local second-hand shops. They aren't anything to look at, but decent steel while I practice honing.

Getting more involved in the process, I figured it was time to lap my stone since it has been used heavily these past several weeks. The retailer told me the stone was flattened when I bought it, so I never bothered when I first got it.

So today I followed the basics found on this and other sites. I have a sheet of 600 grit wet sandpaper on a perfectly flat surface. I started on the 8k side of the stone. It didn't take long for the stone to get to that 'sticky' stage, so I figured it was done. But when I look at it and rub my hands across it, the texture is different in many areas. Around the center of the stone, the 8k feels smooth as a piece of granite and is that bright yellow I remember when it came out of the box. Around the edges, there is still gray discoloration to the stone and the surface feels much more rough.

So my questions are: is the stickiness factor the only thing to consider when lapping a hone? based on what I've said, do I keep going until the entire surface of the stone is smooth as silk, or am I already done?

Thanks in advance for any suggestions.

OK what you need to do is take a pencil and mark a grid on both the 8K & 4K side. This way you can tell if you are flat because the pencil marks will vanish. The lapping stone that Norton sells is probably closer to 200 grit so therefore you can use 200, 250, 350 to lap your stones with. Do as you did with the 600 grit on a flat surface until all of the pencil marks are gone. You can then use the 600 grit or higher to put the stones back to near their original surface.
OH! you might look at the pencil marks as you lap the stones just to see how they are vanishing. The higher level pencil marks will vanish first and as you lap it the rest of them will go.
Hope this helps.

+1 on Bill's advice - pencil grid is the way to go. And just to make it explicit, it's the grit of the wet/dry sandpaper you use that, generally, determines the feel and finish of the surface of the hone after lapping. I'd also suggest two separate bits of sandpaper - one for each side of the hone. And while you're at it, round off the edges of the hone on both sides if it has not already been done by the people you bought it off - reduces the chances of hurting the edge of the razors.

James.

Stickiness means almost nothing. It happens as soon as a large area of the stone is flat, as well as when the slurry builds up underneath the stone.

Follow the above advice but clean the slurry off as much as possible and re-wet the area before beginning again.

That makes a ton of sense. I'll get out my pencil and give it a try. Thanks for the advice.

Well duh . . . OK that pencil grid sure showed me a lot more about what's happening during the flattening process. Thanks for the tip. After reading the responses, I realized that tip was on this forum about a dozen other places, so pols for bringing it up again, and props for answering anyway. Thanks guys.

So one last question. How often do you folks flatten your stones? Mine certainly needed it because I've been hitting it pretty hard while practicing. Is there a good guideline for how often to lap? After every hone? After every 10 hones? Or is it just one of those 'you'll get the feel for it after a while' type of things?

Oh, btw, I'd do the pencil grid thing twice - lap until the pencil grid disappears, then do it again for good measure. Sometimes the slurry that comes off the stone, or the curled up edges of the wet/dry, or whatever, can erase the pencil marks and make you think its flat when it's really not, or not completely.

Anyway, in terms of lapping frequency I tend to go by the "you get a feel for it" thing. And it depends on your hone. Hard ones need less frequent lapping, other things being equal. If I'm doing up older razors that really need a lot of work, I will sometimes lap the Norton after every couple of razors. If it's just edge refreshes I often don't bother lapping for ages. I find the 4K side needs to be lapped more frequently than the 8k side, for obvious reasons.

If you don't mind rubbing your stone away, you can lap after (or before) every session - particularly easy to do if you have a lapping plate, but not so convenient if you use wet/dry. Bottom line, I try to lap as infrequently as I can get away with, and that depends on how much, and what type of, use I'm putting the stone to.

James.

When I cannot get a razor keen with the same honing technique that I have been using on previous razors that turn up keen I will then suspect that the hones need lapping and usually that is the case.
Don't you just love these yes and no answers.

My rule of thumb is, 1st if I feel it needs it, 2nd every 10 razors, or absolutely get of my lazy butt and do it by every 15 razors

Also don't forget that lapping cleans the stone also besides flattening it....

Sounds like you got some good advice. I lap my Norton after every razor because I like how the surface feels when it's fresh. I use a DMT 325-grit hone, so it's quick and easy. If you're honing an eBay razor from scratch, it would probably be a good idea to lap the hone after you work out the edge damage, but before you start trying to get it really sharp.

Josh