Thread: Best Grits For Lapping With

I was talking with Tony Parker the other day and he said he was ready to lap his new Norton with 600 grit wet/dry paper. I remember using 1,500 grit and getting a super smooth finish. THe last time I lapped my Norton I used a Shapton 12,000 on the 8k side (thus lapping them both together, no grit contamination seems apparent after a simple rinsing) and a chinese kitchen hone of unknown, but imagined grit of about 600-800 and the finish is noticeably less smooth.

What is the best grit sand paper to use for the various grit stones in your opinion and what are the differences in honing action one can expect to experience by using a relatively coarse or relatively fine paper?

X

Edit: Kriton has hit it where I missed slightly. What's the best finishing grit to use?

Ok, I am not hi-jacking here, but adding another question to those you raised. I too am interested in grits for lapping - I used a Norton lapping stone (which is pretty damn aggressive) to flatten my 4k Norton - Do I need to use anything else to make the surface "smoother"? Higher grit? I wasn't under the impression that I needed to use a higher grit past the lapping stone?

How can I make a specific grit stone "smoother"? Isn't that an oxymoron or am I a moron?

K

I like to use my 1K Norton to maintain my 4/8K combo. I haven't noticed any improvement on the 8K side when I went to a 1500 or 2000-grit paper, but it's been a while. Maybe I should give it another shot.

I like the feel of the 8K better when I use the 1K stone on it. From what I recall, the 600-grit paper didn't leave it quite so silky smooth.

I don't think it matters much, aside from the way the blade feels during honing. I don't know that polishing would make the stone cut more finely; I suspect that a few strokes with the razor will smooth out any roughness pretty effectively.

Just my 2 cents,
Josh

The finer grit papers risk glazing the hone, where the really fine debris gets ground into the crevices of the hone and clogs it. And the scratches left by the 600 grit paper don't really matter much anyway, by the time you've made a dozen laps or so the razor has smoothed it out just fine.

I deliberately glaze the fine side of my barber hones, because slight glazing seems to allow them to create a finer edge. But it's not really a good thing on the norton.

I too use my Norton 1K for maintaining my 4/8K. However, the grit used to lap with will indeed affect the hone. I found this out (believe it or not) through experimentation. I figured if I was lapping my 8K with the 1K, I should try something more coarse for the 4K side. So I used the 220 side of the Norton and the 4K hone was noticable rougher. Seemed to cut much more like the 1K Norton. So I relapped the 4K with the 1K and it was back to its old self. Given those results, I took out a junk razor to test my 1K/220 combination Norton. Sure enough, after having lapped the 4/8K stone, both the 1K and 220 grit sides seemed noticably less agressive. I re-lapped them both on 400 grit wet dry paper on a granite lapping plate, and they were back to 'normal'.

My problem now is defining 'normal'. If I'm able to change the relative grit of a stone based on what I use to lap it, I guess I'll just have to decide what I like best and go from there. I really hate not having some standard to compare against.

Just another data point,
Ed

I asked Lynn this exact question over the phone and he specifically said that nothing was needed after using the Norton lapping stone. The 4K side will feel rougher for a few strokes after being lapped; however, this has absolutely no negative effect on the razor.

Originally Posted by Kriton

Ok, I am not hi-jacking here, but adding another question to those you raised. I too am interested in grits for lapping - I used a Norton lapping stone (which is pretty damn aggressive) to flatten my 4k Norton - Do I need to use anything else to make the surface "smoother"? Higher grit? I wasn't under the impression that I needed to use a higher grit past the lapping stone?

How can I make a specific grit stone "smoother"? Isn't that an oxymoron or am I a moron?

K

I generally use 90 grit SiC compound on a glass plate to lap all my hones, then use the flattened stones to smooth the next out. For example, I'll use the 1k to smooth out the 4k, and the 4k to smooth out the 8k, all after lapping, which leaves a very coarse surface on all the stones.

I follow the manufacturers directions for lapping the Norton. That is 220 Grit for the 4K Side and 600 Grit for the 8K Side. Then I give a good rub with the Norton Flatting Stone.

I read somewhere and naturally I forgot, that no matter what you lap the stone with, it will never change the grit of the stone.

Thinking about it logically, it can't change the grit of the stone, only the pattern of the surface.

If you lap with paper grit can contaminate- but only the surface and it will wear away. It will naturaly change the characteristics of the hone temporarily while the contamination is present, but it will return as soon as the contamination is gone.

Lapping with a course grit will do the same to the hone surface as it does to the blade's surface.... create grooves. It's the same progression we use in sharpening- start course and get course grooves, move to a finer hone and get finer grooves....and so forth.

Well, logically then, if you use a 220 on a stone you're grooving it to 220 on it's surface making it feel (and in some cases act) much courser because of the resulting grooves which are not related to the hones true grit/mesh. As you hone a blade you're wearing the grooves back and restoring the surface to what it should be- smooth hence the return to the feel and characteristics it had before.

I lapped my hones last night and did some exparimenting. Lapped the 2 barber hones I just got against each other very effectivly. Lapping against my big diamond flat in 900 and 1200 left a slightly more "drawing" feel from the courser grooves, but it smoothed out pretty quick. Lapping against my ceramic fine was an excercise in futility although it flattened my diamond nicely.

Originally Posted by Justme-

... start course and get course grooves, ...

You mean coarse of course.

X