Let's talk granite stones..

Granite beats glass for shop use

Steve Elliott

>I used thick glass for years and was always scratching or chipping it. Then I got a cheap granite surface plate, and like it much better for its durability. It's flatter, too.

Recently I got a 12 x 12" granite tile for a few bucks at a the local Hardware Behemoth, and it's plenty flat enough, too.

Re: Let's talk granite stones..

Dave Anderson Chester,NH

>Granite surface plates or tiles are definately the way to go. I use a 12" x 18" tool room grade B surface plate I bought for $35 from MSC a few years ago. It is 3" thick, weight about 85 pounds and neither moves around on my sharpening bench nor has any sharp edges. It is flat to with in .0001" and I find it useful as a planar surface to assemble small drawers and carcasses in addition to its primary use as a sharpening plate. If you decide to buy one, try to find a seller near you so you can pick it up. Freight charges for 85 pounds can easily double the price or worse.

Re: Let's talk granite stones..

Bob Hackett

>Granite countertops are all the rage right now.Look in the book for your local distributor and take a look at his discard pile.I`d bring a machinist`s straight edge with me.

As an example,I bought 7 1/2 foot by 20" wide,1 1/4 thick black granite for $125.This rock was polished on one face and all edges,all corners radiused.

After I cut out 2 window sills and a small table top for SWMBO(To put plants on).I still had more than enough(20x24+)to use in the shop.If you don`t want to buy a diamond blade($80)and deal with cutting most places will cut and polish the edges for a small fee.

The best part about all this is that the underside of this granite is moderately rough so when I`m done sharpening I just flip the stone and flatten the waterstones.

It didn`t take much convincing to get LOML to look at the stone and once we settled on a color,she even paid for it with no problem.Zero drain on the "rust fund".

Mainely,Bob

Re: Granite countertop slabs

Ted Shuck

>I went dumpster diving at a local granite countertop contractor last year. Thought I had found the mother lode! Lots of nice pieces about 1 1/4" thick and up to 30" long. I picked up about 4 pieces. When I got them home, I checked them with a straightedge for flatness. Only one was "reasonably" flat, within about 0.001". Others were dished up to 0.02". Now, no cook is going to really notice this on a countertop, but it won't do for flattening plane soles.

I want to emphasize what Bob said, "bring a machinist's straight edge".

If you are going to use the granite slab as a lapping plate, don't expect it to stay flat for very long. I have a granite tile that I use under drywall screen for flattening the backs of blades and chisels. It is starting to get dished. Keep your good granite slab as a reference and use something expendable for lapping.

Ted

Re: Granite countertop slabs

Wendell @ Murphy, TX

>"If you are going to use the granite slab as a lapping plate, don't expect it to stay flat for very long. I have a granite tile that I use under drywall screen for flattening the backs of blades and chisels. It is starting to get dished. Keep your good granite slab as a reference and use something expendable for lapping."

Wouldn't this only be a problem with dry wall and things like diamond paste or carbide powder? I wouldn't think there would be any dishing using a reference slab in a Scary Sharp system since the abrasives never really touch the surface.

Wendell

Re: Let's talk granite stones..

Wiley Horne--Glendora CA

>One of the very best investments ever! Makes checking and truing the soles on woodies so simple and fast. The 12x18 that Dave mentioned is a good size, and has almost a 22" diagonal, so that you can true a pretty long plane on it. I bought a 9x24 from Japan Woodworker, which cost more than it should have because of the special size, but then it fit into the space I had for it. One thing that was a pleasant surprise: Even the cheapie plates come with a lab report on them, where they plot the deviations from datum. Mine is a Grade B, but just missed being a Grade A--as Dave said, about 0.0001" off. Dave's right-- pick it up locally and save yourself the shipping.

Wiley

It does touch the surface.

Dave (Arlington, VA)

>Hi Wendell -

Good question.

Most of the drywall screen that I've seen has abrasive on both sides. So, while you're pressing down to abrade/flatten your waterstone with the grit on the top at the same time you are abrading (somewhat) the granite underneath with the grit on the bottom of the screen.

Regards -

Dave

Re: Granite countertop slabs

Ted Shuck

>I agree. If you are just using it for scary sharp, where the grit is backed by paper or mylar, it should not be a problem. What I meant by using it as a lapping plate was with abrasives directly on the surface of the granite.

Ted

Re: Let's talk granite stones..

Murray in Palo Alto CA

>Enco also has the inexpensive stones, and if you look around, they often have free shipping for orders over $50.

Re: Let's talk granite stones..

Dave Anderson Chester,NH

>Interestringly enuf, Enco was bought by MSC about 2 years ago so while they operate separately, they are the same company.