Thread: Lapping with your hones

I have read that you can use two hones to lap one another to even out the flat spots, instead of messing with sand paper or dishing out for a lapping stone. I am wondering if this would be possible with my set - a 4k/8k norton, a yellow belgian coticule, and a chinese 12k.

I was wanting to know because if I couldn't lap these stones using each other I'm going to get some wet-n-dry because I currently only own two straights and will probably only ever own four (I'm looking to get a boker and a dubl duck to match up with my tadross and kutter).

I've read about using this method. I never have as I am paranoid about contaminating one stone with the grit from the other. I've never used sandpaper either for the same reason though I know that many do successfully. I got a 325 diamond plate early on and have been happy with that. Someone who has done it with hones will probably be along to tell you how that worked for them.

I've used this with Nortons, Naniwas, Nakayamas, coticules, and barber hones. I've never seen any hint of grit contamination in any of the combinations I've used, but then, I've only done Nortons with Nortons, Naniwas with Naniwas, etc.

Considering what you've got, I'd suggest that you use the Chinese hone to lap all of the other hones. The thing is so hard that you're not going to wear it out, it's cheap, and it actually benefits from occasional refreshing anyway. You certainly will want to start with a flat Chinese hone. Once you have that flat, I'd lap the Norton 8k, then the coticule, and finally the Norton 4k. Though if you're using water like you should be, cross contamination shouldn't be much of in issue anyway. Also, you can put wet/dry sandpaper on top of a wet Chinese hone and use that as your flat lapping surface. The wet/dry sandpaper works surprisingly well for lapping but embedded grit can be a concern, though in my experience it rarely occurs. Generally though just rubbing your hand over the hone surface will dislodge any grit.

Edit: I forgot to mention the fact that the Chinese hone, being relatively fine, will by itself be a slow lapper but I am speculating that grit released from the hone you are lapping will help to speed it along and you'll want to use minimal water during the lapping but copious amounts for rinsing afterwards. Also, with DMT plates it's recommended that minimum pressure be used. This does not apply to the above lapping system--you can push as hard as you want. This method is not ideal, but it's working with what you've got. Sandpaper would definitely help it along.

If you use one to lap another then over time one will maintain a 'dish' and the other will be convex. The softer of the two will conform to the shape of the harder stone, but the harder stone will also be worn somewhat during this.

If I had one stone that was dished, like this: ( and a flat hone like this |,

Then when I bring the two together I have this: (| If you rub these two together, then the high spots of the dished stone will rub the ends of the flat stone and wear down the ends. You end up with one stone slightly convex and the other slighly concave. Try honing a straight razor on that. It would suck.

The effect may be minimal, but it might be the cause of crappy edges in the future. If you're worried about grit contamination, then get Some super coarse sand paper. Get a three inch wide belt sander belt at 40 grit and cut it so that you have a long flat belt. Lay that on something flat (granite tile is five bucks from Lowes...) and LIGHTLY flatten your stones. Then rub your flattened stones together to improve the surface finish. If a piece of 40 grit got stuck in your stone, it'd be big enough to flick it out with your finger nail.

If I ever lose my diamond plates, though, I'll stick with wet/dry sandpaper at a low grit. I've never had a problem with it.

The Chinese 12k would be a PITA to flattin with, in my opinion. Would it work? Maybe. Try it. I'm thinking that it'll stick like super glue to a high grit stone. By the time you get an 8000 grit stone flattened properly with a chinese 12k, you could have gone and applied for a job at McDonalds, and already had your first paycheck and bought a DMT XXC. And probably have scored a few free fries and shakes.

I use a well worn DMT XXC for low grit flattening, and a DMT C for higher.

I use one hone to lap another only after they have been lapped flat on a lapping stone or sandpaper. I do it just to remove the scratches from the previous method. If all you use is one hone to lap another there may be issues with the flatness as mentioned above.