Granite surface plate

[Bearzilla911]

Picked up a granite surface plate for waterstone flattening and sandpaper sharpening. Only been using it for a few days, but it’s amazing.




This thing is 12” x 8” x 2” and weighs about 25 pounds and they say it has a flat accuracy of .0001”. I was using a 9 x 9 flat tile before for sandpaper sharpening. And just sandpaper on my oven top for Waterstone flattening.



What are you guys using for these tasks?

 

[Rob Babcock]

I have a similar granite slab, very handy!

 

[kwackster]

A thick bookshelf made of hardened glass.

 

[Diemaker]

3ea 12" black granite tiles. Having 3 allows me to flatten them when they get dished from use.

 

[Obsessed with Edges]

I have one about the same size (12" x 10" x 2"). I've found it perfect for sandpaper sharpening as well, as a full sheet of wet/dry is almost a perfect fit to it.

 

[Ilikesharpstuff]

If you flatten your stones with loose silicon carbide grit directly on the granite you'll dish it out pretty quickly. Reputable machine shops that use granite surface plates for inspection and setup will have them calibrated annually. If used frequently they almost always need to be lapped/calibrated back into spec, and that is just from sliding steel around on them. While the level of flatness you need for what you're doing is probably not anywhere near the plate's original spec, just know that it will wear over time...whether or not it will be enough that you'll notice the difference is anybody's guess.

 

[Bearzilla911]

I planned on wet dry sandpaper on top of the granite for flattening, I have never tried the loose grit method. I have trouble seeing in my head how that would work better as I have had no issues with sandpaper on a flat surface..

 

[Diemaker]

I planned on wet dry sandpaper on top of the granite for flattening, I have never tried the loose grit method. I have trouble seeing in my head how that would work better as I have had no issues with sandpaper on a flat surface..

When lapping a large surface loose abrasive is worlds better than fixed. As in one works and the other doesn't, at least comparatively. If you have never tried it you must, yes, must! Sand paper may work for sharpening a knife or plane but those are not large surfaces like a stone, even a small stone. Granted it is hell on your flat plate, which is why you need 3 of them so you can flatten them with each other.

 

[Bearzilla911]

When lapping a large surface loose abrasive is worlds better than fixed. As in one works and the other doesn't, at least comparatively. If you have never tried it you must, yes, must! Sand paper may work for sharpening a knife or plane but those are not large surfaces like a stone, even a small stone. Granted it is hell on your flat plate, which is why you need 3 of them so you can flatten them with each other.

Duly noted, thanks for this info, I'll have to give it a shot. I'll definitely admit, some things are not intuitive, ha.

 

[FortyTwoBlades]

Can confirm. The loose grit method is SO much faster it's unreal.

 

[Diemaker]

The Matrix stones would never have happened if we dressed them with sandpaper. It wasn't until we tried dressing them on loose abrasive that we liked them. I feel the same way with my Alox stones as well. You have to try the two methods of dressing to understand.