Thread: Lapping a 4k/8k

I took a lot longer than that to lap mine. I ended up buying the 4x10 DMT 325 and it worked quite well. Those corners are a big PITA, but at the same time, the edge of your razor isn't going there, anyway.

That said, I've spent at least two and a half hours total lapping mine, if not more. I'm still planning to take off more material, as I think I could stand to get down to some smoother stuff, especially on the 4k side. It feels sort of rough when I'm honing on it.

I think I'm just gonna buy a DMT. Everyone seems to be praising them. I thinkk ill order it from SRD since my local Lee Valley charges $90 + tax for one.

Originally Posted by canuckblade

I think I'm just gonna buy a DMT. Everyone seems to be praising them. I thinkk ill order it from SRD since my local Lee Valley charges $90 + tax for one.

Well, the one at Lee Valley is 4"x10". You're looking at $73.79 for the smaller plate by the time you factor in shipping. Now, don't get me wrong, you could do a lot worse than to buy something from the fine gentlemen at SRD, as they are top class, so the final decision is yours. I decided to pony up the extra ~$20 and get the bigger plate, which gives a nice large lapping surface for the 8"x3" stones.

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.

Ok, so I went into my basement and found an old picture frame and removed the glass from it. I tried and lapping on that, and wow what a difference, both sides the pencil grid disappeared about 98% in about 5 minutes of lapping.

I guess my countertops aren't that flat after all :s

Here may be something that helps a few people out. I've used what's called a granite surface plate to lap my stones. They come in many sizes and they are used to calibrate precision measuring instruments like some I use in the aviation industry. They are usually within one ten-thousands of an inch of being flat, about 50 times thinner than a piece of paper. And they are considerably thick and will last you forever. I use them with high quality wet sandpaper to lap my stones and it works like a dream. I'm sure you can get them from a few places, but I bought mine from an industrial tool company called Grizzly for about $30 (18"x18" and it weighs about 100 pounds). Obviously too big for a counter-top but they do have much smaller ones 9" x 12" and 6" x 8". Hope this helps someone.