Thread: How flat is flat for a hone

And… just so you know… glass is not flat.

Try lapping a piece, with a diamond plate, flat-ish, but not flat.

A Chinese stone will eat a Diamond plate. Loose Silicone Carbide grit and a steel cookie sheet, is fast and efficient, about $15 buck will do several stone. Search lapping Ark stones.

The cookie sheet and Wet & Dry, on a flat concrete floor works well for finishing grits. Once flat it goes quickly. Hope you used a respirator with your belt sander.

The EBay Chinese stones run the gamut on grits, but none I have seen are close to 12 or 15k.

Originally Posted by Euclid440

And… just so you know… glass is not flat.

Try lapping a piece, with a diamond plate, flat-ish, but not flat.

A Chinese stone will eat a Diamond plate. Loose Silicone Carbide grit and a steel cookie sheet, is fast and efficient, about $15 buck will do several stone. Search lapping Ark stones.

The cookie sheet and Wet & Dry, on a flat concrete floor works well for finishing grits. Once flat it goes quickly. Hope you used a respirator with your belt sander.

The EBay Chinese stones run the gamut on grits, but none I have seen are close to 12 or 15k.

Wel what can I say! I kicked this of with the intent to learn what others do and it seems to have morphed into something entirely different than I intended. I have little to no experience with flattening a honing stone out side of making one from sand stone.
Nope. No respirator. Tried to get it on but it was not cooperating. I sanded a couple of seconds and walked away. Was in a well ventilated area.The finish up with a 400 grit to achieve engineer straight edge flat. Short of NASA equipment that's as close to flat I am going to get. As I mentioned the stone released a lot of powder--thus making me suspicious that it was 15,000.
The grit was not the important question. It was have you done it? How did you do it? What did you use? What suggestion would you offer? That was it.

Euclid440
Glass is not flat and neither is the world. I have looked at the prices of the diamond flattening hones and Whe-e-e-u-u! My retirement income would never permit me to pay such a price. When I was younger I had time and money available wherein an accumulated hones I used on my wood working tools. Now that all of that is sold, kitchen knives and SR"s are all I sharpen.
The stone I purchased was quarried in the Guangxi province of China. It does not list a grit, but simply call it a finishing stone. I had to search for an approximation of the grit which I arrived at 12,000. I may have mistakenly said 15,000. The closest lapping film from 3M is the 1 micron sheet at 14,000. According to Best Sharpening Stones.Com, under lapping (a blackish box in the middle of two 80x magnification of blade edges, which is impressive). A .3 micron sheet is suppose to be equal to a 50,000 grit. Prove it! I sure can't, all I can do is trust 3M to know what they are doing, and have faith in the product. I guess all grits come down to a statistical count.
Belt sander and particle emission. Wow! What a cloud it produced. I was using a 220 grit belt. The sander was used to expedited the process, and no I did not wear a respirator, not for the lack of trying as mine would not cooperate. Anyway I was in a well ventelated (sp) area. The amount of dust that flew from the stone made me question the quality of the stone despite the extreme smoothness of it even after the course sanding belt. My engineers straight edge was used in a darkened area with a flashlight. No light passed beneath the straight edge.
My original intent with this post was to query whether anyone had flattened a stone, how they did it and what suggestions they might offer. Thank you for your thoughts regarding the issue, as I have contemplated purchasing a Japanese lapping stone or the Norton lapping stone.

Where do you find loose silicone carbide?

Don't buy the norton. Wet and dry sand paper will work.

The norton lapping hone is only for synthetics, not natural stones.

Originally Posted by aalbina

My wife would literally shoot me in the head! Good for you and glass is a great way to go.

Adam

Two things: I make sure the burners are off and cool (the burners are embedded in the flat glass top)...and I make sure my wife is out.

Originally Posted by Whizbang

Two things: I make sure the burners are off and cool (the burners are embedded in the flat glass top)...and I make sure my wife is out.

Cute Whizbang. Sounds like something I would do.

Currently my stones, uh, hones are or seem to be rather flat according to my straightedge. The lapping stones were not that expensive, but I questioned in my mind if there wasn't another way to do this. The bench sander worked, but short bursts and constant checking with the straight edge was required, or at least for me it was. Getting the right pressure on a spinning sanding belt is not that easy. I never thought about marking it with a pencil. Nervous about felt markers given the apparent softness of this stone. the marker could possibly bleed deeper into the stone. At the moment, according to the straight edge and my less than perfect eye sight it sure looks flat. I used a small four LED flashlight to shine at the edge of the straight edge and no light was visible at any section I rotated the straight edge. I followed four parallel points with the longest edge then horizontally down the narrow width at eight spots then several vertical checks. No beam of light passed beneath the straight edge.
At this point I'll not be using lapping stones since there are other options except for diamond lapping hones.

GotGrit.com has all the grit you will need 60 to 500, a quarter ounce of each, (about $15), will do several stones, and a steel cookie sheet from the dollar store. A teaspoon of 60 grit and a squirt of water will get you flat in a few minutes, no dust in the air. Then run up the grits, switch to wet and dry up to 1k.

You only have to do it once. Lap it just like an Ark.

Forget the Norton lapping stone, it is worthless.

You can buy a 400/1k diamond plate for $35, from Chefs Knives to Go.