Thread: Natural Oil Stones: How Flatten?

How might one go about flattening natural oil stones?

Flattening them is easy just a bit of work use a Low grit DMT (120) or Wet-r-Dry sandpaper on a flat plate..

Prepping the stone for razor use is a bit more involved, and more of a YMMV type routine..

Most use a successive progression of higher grits of DMT and Sandpaper then usually another stone is involved and many use some type of metal as a final stage of polishing with oil.


Hint: if you have expensive Waterstones anywhere near an Oilstone, "Smith's Honing Solution" is a safer alternative to real Oil

Hi Glen.

About what grit Wet/Dry sandpaper would you recommend? I have course, medium, fine, and extra fine oilstones; with those designations relative to sharpening a knife. Most of them look flat to me, but from what I've been reading about it; it seems flat for razor honing is to a tighter tolerance than the eye can distinguish.

Would a laminate (Formica) table generally be flat enough to lay the sandpaper on? How about a piece of common window glass?

Originally Posted by TomBrooklyn

Hi Glen.

About what grit Wet/Dry sandpaper would you recommend? I have course, medium, fine, and extra fine oilstones; with those designations relative to sharpening a knife. Most of them look flat to me, but from what I've been reading about it; it seems flat for razor honing is to a tighter tolerance than the eye can distinguish.

Would a laminate (Formica) table generally be flat enough to lay the sandpaper on? How about a piece of common window glass?

That would depend on the stone, I would start with 180-220 grit and depending on the stones grit will determine what sandpaper grit I'll finish with.

On most stones I would stop after 400 grit sandpaper.

window glass would probably work well.

Originally Posted by gssixgun

Prepping the stone for razor use is a bit more involved, and more of a YMMV type routine

if this is to be used on razors (assumption only) I would make sure this is natural and suitable for razors. I have seen heaps of old shed style oil stones on ebay advertised as "extra smooth" or mistaken as natural aiming for the razor market but are no where near suitable. Just something for the OP to be aware of.

I'm not sure if its a lack of cleaning to see what it is (Getting past the thick black oil) or a lack of knowledge

TomBrooklyn,

I would add if your natural is of the harder types e.g. novaculite type (hard Arkansas etc.), you might also need to order in a few hundred-weight of elbow-grease

My translucent Arkansas was a real sod

Have fun !

Best regards

Russ

What kind of stone? Photos, we need photos.

How out of flat are they? Some stones are very hard and often is easier and better to lap the bottom side flat.

The best way I have found is loose Silicone Carbide grit, GotGrit.com has all you need and fairly inexpensively. A quarter pound will do a few stones, you do not need much one plastic teaspoon will get you flat. I start at 80 grit.

Buy a large cookie sheet from a Dollar store, put the sheet on a flat piece of concrete, your shop floor. This will allow you to put all your body weight on the stone. It does not matter that the floor is not “perfectly” flat, the progression will get you there. At the rough grit you are just hogging off material.

Sprinkle on a ½ teaspoon of grit on the sheet and wet with water with a bit of liquid soap to make a slurry, mark a grid on the stone with a sharpie and start lapping. Pencil will wash off on the first lap.

Spin the stone frequently 180 degrees to put even pressure on each end of the stone.

Once flat and grid is removed, remarked the grid and do light laps, less pressure to begin to remove scratches on the stone face. You will feel when the grit stops cutting.

Work up the grit progression switching to Wet & Dry for higher grits. How high up the grit progression depends on the stone and hardness. Progressive grits will go much faster once flat.

You can use Wet & Dry for the whole progression, but loose grit is much faster getting to flat, for really hard stones be prepared to go through some W/D if you don’t use loose grit with a hard stone.

A stone does not have to be perfectly flat as the razor will ride on the high spots, but do get it as flat as possible, turn the stone frequently.

The good news is you only have to do this once.