Thread: flattening with sandpaper

I'm new to straights and I'm slowly coming up to speed. I'm about to flatten a couple of stones on glass with sandpaper. One is a new Norton 4000/8000 and the other a Swaty. My question is; if the stones are of a much finer grit than the sandpaper (1000 grit) wont the process leave the stones in a condition approximating 1000, more so than 4000/8000 or what ever grit the Swaty happens to be? Does it cease to be an issue after the first use?

You are sanding stones not wood, whatever material is sanded off of the stone will only expose more of the same material at the same grit.The stone will be undamaged, unchanged with the exception that it will now be flat enough to make contact with the entire length of the blade.

I agree with the above. The abrasive grains in the hone will not be altered. The "texture" of the hone will change but only for a short period of time. BTW, I lap my Nortons before each honing session on 1000 grit.

here is how i see it...

If you use 1K paper to flatten the 8K, the surface will at first be like an 8K stone, with grooves 1K deep.

However the W/D sandpaper will soon become dull as it abrades the uneven surface of the stone (the paper is honed by the stone too). But by that time the slurry (8K) between the stone and the paper will do the abrading of the stone and make the stone flat and 8K smooth.

Whatever. It works. That's the important thing.
If you don't flatten the hones and regularly, the surface can quickly develop a fault.
I used a hone that had not been leveled and it had a very slight dome. The result when honing was to very quickly turn a straight edge into a reverse smile. There a sort of an irony in there somewhere.

Originally Posted by English

Whatever. It works. That's the important thing.
If you don't flatten the hones and regularly, the surface can quickly develop a fault.
I used a hone that had not been leveled and it had a very slight dome. The result when honing was to very quickly turn a straight edge into a reverse smile. There a sort of an irony in there somewhere.

Irony, for sure. Thanks for the input guys.

Originally Posted by smythe

here is how i see it...

If you use 1K paper to flatten the 8K, the surface will at first be like an 8K stone, with grooves 1K deep.

However the W/D sandpaper will soon become dull as it abrades the uneven surface of the stone (the paper is honed by the stone too). But by that time the slurry (8K) between the stone and the paper will do the abrading of the stone and make the stone flat and 8K smooth.

This is a helpful post. Thank you. I'm using a glass bed and 1000 grit paper. I see the 8000 side makes a nice yellow slurry. I'm not sure what I'm doing and I was washing the slurry off the stone and the paper and re-honing. Maybe I should use the slurry. Any way, I have done the 4K and the 8K using one piece of paper. Moving my stone back and forth with no down ward pressure. I applied a little pencil to the 4K side to watch it remove. It never did come out completely and I had thought I applied it lightly. I was wondering. How much lapping of stone hone should I do? How can I reference or determine a flat surface?

Lap until the pencil marks are gone then a little bit more.

Good tip, Randy.

You can apply pressure at the start but ease off and let the weight of the hone do the job at the end.

When the hone is flat it will suck to the sandpaper. The gerater the vacuum the flatter the hone.

If you have a straight edge, you can lay it along and move it around the flattened surface looking for light gaps.

If you have a slurry stone (that has been flattened) or another hone (that has been flattened), and you put water on the surfaces and rub the stones together, you will find a strong vacuum stops the stones sliding easily if they are fully level.

I don't want to fall short of the best job I can do. I simply need to realize when that occurs. I will get some more coarse sandpaper and keep on it till the pencil marks go away. Thanks. Im seeing the light I think.