Thread: Lapping a 4k/8k

Tried lapping my new 4k/8k on 400 grit wet/dry sandpaper and my bathroom granite countertop.

I got about 90 % flat and smooth (confirmed with pencil grid) on both sides after a fair bit of work, but for some reason some of the corners and very edges on both the 4k and 8k won't go flat no matter what I do.

I'm about to cave and just buy a DMT.

It's always the last 10% that's killing you, even with a DMT....

I really can't say enough about owning a 325 DMT plate...buy the big one 3x8 inches. You will use it all the time, lap everything with it and you can use it for major chip removal.

Are you sure the counter top is Exactly flat? You may need to get a cheap tile from home depot or something for a flat surface.

Like Blix said, the corners are always the tough last bit.....So close! yet so far ..

I just can't figure out if my surface isn't flat enough or I'm just not lapping long enough, but the corners/edges are taking forever, I've already gone through 2 sheets of 400 grit sandpaper

Two sheets of 400 grit sandpaper is not all that much if it was the initial lapping. After the initial lapping, it will go much more quickly.

So do you recommend i lap some more? I took about 15 minutes for both sides before I gave up. I was just concerned because other ppl on here are saying it shouldn't take more than 10 minutes tto lap a new norton

Originally Posted by canuckblade

Tried lapping my new 4k/8k on 400 grit wet/dry sandpaper and my bathroom granite countertop.

I got about 90 % flat and smooth (confirmed with pencil grid) on both sides after a fair bit of work, but for some reason some of the corners and very edges on both the 4k and 8k won't go flat no matter what I do.

I'm about to cave and just buy a DMT.

It took a while with the DMT but I found that with mine the corners on the 8k side did slope down a bit. You could just barely feel it when you ran a finger over the lapped portion of the hone onto one of the corners.

Horn

This is the best thing I have read about lapping and seems to make the most sense to me. It is from the pyramid honing guide written by Lynn
"When I first learned this process, I learned it on a Norton Combo 4K/8K stone and have worn out the 4K side on 8 stones since that time. When I first started, I was shaving right off the 8K side and had fantastic results. This was before I discovered the natural finishing stones and then the pasting or spray media. On the new Nortons, I recommend lapping off about 1/8 of an inch of the 4K side to get past the grainy feeling the newer stones have. Once the 4K side starts to feel smooth to the touch, you are there.

When we talk about lapping the stones, I really lap more to make sure I get the swarf off the stones and clean them up for the next use more than I am concerned with a millionth degree of flatness. Mostly flat is usually all you need to hone your razor so long as the edge and spine remain on the stone throughout your stroke. OK purists, don't get upset, as flat as you can get the stone is not a bad thing either. I have seen many a dished out or bowed hone from the old days and people were using them and shaving. I was using a pumice stone before Norton came out with the flattening stone and needles to say my stones were not perfectly flat, but I honed thousands of razor that were great shavers without difficulty."

Hope this helps

Originally Posted by Castel33

This is the best thing I have read about lapping and seems to make the most sense to me. It is from the pyramid honing guide written by Lynn
"When I first learned this process, I learned it on a Norton Combo 4K/8K stone and have worn out the 4K side on 8 stones since that time. When I first started, I was shaving right off the 8K side and had fantastic results. This was before I discovered the natural finishing stones and then the pasting or spray media. On the new Nortons, I recommend lapping off about 1/8 of an inch of the 4K side to get past the grainy feeling the newer stones have. Once the 4K side starts to feel smooth to the touch, you are there.

When we talk about lapping the stones, I really lap more to make sure I get the swarf off the stones and clean them up for the next use more than I am concerned with a millionth degree of flatness. Mostly flat is usually all you need to hone your razor so long as the edge and spine remain on the stone throughout your stroke. OK purists, don't get upset, as flat as you can get the stone is not a bad thing either. I have seen many a dished out or bowed hone from the old days and people were using them and shaving. I was using a pumice stone before Norton came out with the flattening stone and needles to say my stones were not perfectly flat, but I honed thousands of razor that were great shavers without difficulty."

Hope this helps

yea i guess with all the modern advances in technology and precision, people get concerned with the small details. Im a student on a budget, so I'm mostly just concerned with maintaining and perhaps sharpening my razors and any future ones I aquire. I would like to get into restoring razors in the future though. Gotta keep my R.A.D. in check until then haha.

I'll probably invest in a DMT just becaue its easier, more consistent, faster, and lasts longer. It's always worth to spend money on quality tools that will serve you well in the long run, I think. It actually ends up being more cost efficient in the long run.

Thanks for everyone's input so far. I guess i'll try to lap it some more.

I can't imagine the corners being important for honing - my strokes never go to the hone edges. I'd say just use it as it is, as you wear it off you may get to end-to-end flat, or you may not, it just doesn't wear off that much.