Flattening Waterstones - What works best?

[David Weaver]

A friend and I have been having a back and forth about flattening with waterstones (and sharpening in general). I like to do all of the initial flattening on a new chisel or blade with wet and dry sandpaper on a plate glass backing to avoid flattening the waterstone after that exercise.

The friend of mine insists on using the waterstones for the whole process, but he doesn't like having to flatten the waterstones when he's done. Both of us came to the conclusion that we don't know of a better way to do it than using wet and dry sandpaper on float glass. Neither of us have purchased any of the flattening diamond stones because we can already flatten with the wet and dry, but we're game if it's faster.

Does anyone on here use both methods, or has anyone used both methods, and have any comments about the speed of the diamond stones (and the flatness of them) vs. using float glass and wet and dry?

[Mike Henderson]

I used to use sandpaper on glass to flatten my waterstones but now use a DMT diamond plate (Extra coarse/coarse). Both work well but the diamond plate was just a bit more convenient.

Additionally, I use the diamond plate to flatten the back of chisel and plane blades before I put them on the waterstones. The diamond plate is faster.

Mike

[steve swantee]

Hello David, I can't remember where I read about this method, but a while back I decided to give it a try. There is a concrete cinderblock outside my shop door, lying on it's side. Yup, the kind you use to build a foundation. When it's time to flatten a stone, I just grab a pail of water and splash a little on the block, and start to rub the stone on the flat surface of the block. I flatten both sides, and put a little chamfer on the corners, adding water as needed, and it only takes a couple of minutes - and best of all, it doesn't create any mess in the shop. My stones come out nice and flat, and although the block does leave some scratches in the surface of the stones, they are not deep enough to cause any problems. Over the last year the surface of the block I have been using has become a little less coarse, but seems to still abrade the stone well, but if it ever becomes too smooth, just flip it over, and you've got a fresh surface to use. Pretty low-tech, but it works.

Steve

[Jim Becker]

I have a Norton "flattening" stone that seems to work fine. In fact, the weekend before last was the first I used it after purchase and I was very pleased with the result.

[Derek Cohen]

I use either a cheap 400 grit Chinese DMT-knockoff diamond stone in my hand, or 220 grit drywall mesh on a flat surface.

Regards from Perth

Derek

[Alan Turner]

We use SC grit, about 80 or 90, on a scrap of granite. A bit messy, but quick. We generally do about 6 at a time, and then clean up the slurry/mess. Note that you need to use the entire scrap or you will belly it out, like the old oilstones. Scraps are free from the dumpsters behind granite shops.

[Jim Newman]

I have used waterstones (which wear and dish quickly) to sharpen/flatten for years and oil stones before that. I then went to coarse diamond plates, which work well but a lot of work, and 60/80 grit sandpaper before continuing the grit progrssion to 1500 grit, on glass plate initially and then a granite surface plate. The granite surface plate/sandpaper made a world of difference for me and has earned my seal of approval as it is much easier, no lubricant involved and I get consistently excellent results and all I need to clean up is an old paint brush! I used to use my coarse diamond plate to flatten my waterstones, then got a norton flattening stone, but still have to use my diamond plate to be sure it is flat as I know the diamond plate is flat to + or - 0.002". The granite surface plate is flat to 2 orders of magnitude better or 0.00002" and my ability to get a mirror polish/flat surface on the backs and bevels (meaning very sharp edges on my chisels and plane blades) increased considerably.....coincidence? I am not a pro like Alan and others here, but am not a newbie to sharpening things. Getting a clean, perfectly flat, mirror polished back is absolutely essential to getting a sharp edge on woodworking tools and the true "secret" if there is one....at least that is what I have gotten out of my years of experience and as Mike Dunbar says, when you get your first true mirror polish on the back, it is your first "aha" moment in sharpening. Thank God for people like Mike Dunbar and others here who have helped us of less experience!