# Granite for flattening



## Yacman23 (Sep 16, 2016)

Does anyone know if it's acceptable to use a remnant of countertop granite for flattening plane soles?


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## rossboyle52 (Dec 31, 2012)

Works for me. I have been using a piece of remnant granite counter top to flatten chisel backs and plane irons for years. I have used cement blocks to flatten plane soles


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## cooltimbers (Apr 11, 2009)

I assume you mean as a substrate to attach sandpaper to? If it is flat, then I guess so.


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## BurlyBob (Mar 13, 2012)

Definitely!. Like Ross I've been doing it for several years. I've got one sizable piece set up with 6-7 pieces of wet/dry paper from 220 to 2500 grit. I've also got 3 longer 4"+ slabs maybe 28" long with double lengths for flattening plane soles. I'm very satisfied with the results.


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## TheFridge (May 1, 2014)

I have a large sink cutout. I get the same scratch patterns no matter where I put the paper. I'm happy.


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## BillWhite (Jul 23, 2007)

Sink cut-out here as well. 3 cm thickness and flat. Free. What's not to like?
Bill


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## wormil (Nov 19, 2011)

I have several granite pieces and none are truly flat.


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## HokieKen (Apr 14, 2015)

I have a granite surface plate that is dead flat and I have two 12" granite tiles that are pretty close to flat. Close enough for dressing chisel backs and planes. But, I had to buy 24 tiles and sort through them to find 2 that were flat enough to suit me. I just returned the rest to Lowes. Granite is an excellent substrate and is very stable but isn't usually truly flat unless it was intentionally ground to be that way. Most of it is slightly dished. I'd say check it and if it's flat enough, then use it.


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## HickWillis (Aug 5, 2016)

For the folks who have sink cutouts or whatever it may be…are they from when you bought granite for your kitchen, bathroom etc? Did the granite company charge you anything to keep the cut out?


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## Unknowncraftsman (Jun 23, 2013)

I have not seen any granite scraps big enough to work with flat enough for me.
They are not very thick and will flex.
I paid 185 for my 30long 24w 4thick.Its not super precision but I use it a lot for a reference surface.And small assembly table.

Aj


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## BillWhite (Jul 23, 2007)

Sink cuts are waste. The granite fab shop here throws the broken splashes and cuts in the dumpster. They do not charge me for the remnants.
Bill


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## BurlyBob (Mar 13, 2012)

Ditto what Bill said. the outfit I found was glad to have me haul off some. They have to pay to dump the scraps.


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## HickWillis (Aug 5, 2016)

Good stuff, thanks fellas. I have a granite shop near me, I'll stop in and see if they have any scraps.


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## JayT (May 6, 2012)

> Ditto what Bill said. the outfit I found was glad to have me haul off some. They have to pay to dump the scraps.
> 
> - BurlyBob


Same here. Stopped at a countertop shop and asked if I could buy a small piece of cut off. The guy laughed, pointed me at the waste pile and told me to take as much as I wanted so they didn't have to pay to dump it.

A couple things I learned at a Woodworking Show session with Rollie Johnson. Try to find the darkest granite you can, darker means denser and more stable-that's why reference plates are made from black granite. Second, try to see if you can find some that has been surface ground flat, but not yet polished. It will be the flattest at that point, as the polishing process can introduce some small imperfections.

Regardless, a decently flat piece of granite will get your planes flat enough to use.


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## kelvancra (May 4, 2010)

I use a Makita and a Milwaukee variable speed grinders to work granite. I dribble a bit of water on the bits, pads and stones to GREATLY extend their life (I use a 3/8 hose off an adapter, with a valve, mounted to a garden hose). I run the grinders at near the lowest settings.

The pads, stones and router bits are available all over the Net. I have pads ranging from 50 to 6,000 grit. The stones are large and just spin on, but only run about ten bucks. They are about forty or fifty grit and will remove a lot. Perhaps too quick for these purposes, since I've used them to round over edges.

If you had a piece of scrap that was close, you may only need the 100 or two hundred to start. Finer grits would only be necessary to bring a polish. In fact, if you were within a few thousand's, you could touch the face with 800 or 1000 and check it.

I suspect most tiles and slabs are going to be fine for most of us.


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## tshiker (Oct 25, 2014)

If for some reason you can't find or don't want scraps there is this option, http://www.grizzly.com/products/18-x-18-x-3-Granite-Surface-Plate-No-Ledge/G9653


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## splatman (Jul 27, 2014)

Would it work to rub 2 sink cutouts face-to-face with some water and abrasive to grind them totally flat?


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## Cooler (Feb 3, 2016)

Granite is ground, and depending upon who did the grinding it may be flat or it might not be.

Glass, on the other hand, is floated and will be flat. I've used glass to "machine" a small engine cylinder head when replacing a gasket.

You can get double strength glass almost anywhere.

Burnish the edges of the cutout granite and put on some feet and you have a cutting station.


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## splintergroup (Jan 20, 2015)

The cheap import granite surface plates are perfect for that. I think I got my 9"x12"x3" for under $20 and free shipping a number of years ago.


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## Cooler (Feb 3, 2016)

> The cheap import granite surface plates are perfect for that. I think I got my 9"x12"x3" for under $20 and free shipping a number of years ago.
> 
> - splintergroup


Grade B surface plates (cheaper than Grade A) are generally guaranteed flat within 0.0001" (one tenth of a thousandth).

In our QC office we have a 3' x 4' x five or six inches thick. It rests on a robust steel stand. I have no idea what it weighs, but heavy for certain.


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## smance (Jul 8, 2015)

If you don't want to pay ~$80 in freight, I grabbed mine off amazon. They have a few different sizes.


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## SignWave (Feb 2, 2010)

> Would it work to rub 2 sink cutouts face-to-face with some water and abrasive to grind them totally flat?
> 
> - splatman


You can do this, but it would take 3 pieces to get totally flat. If you only have two, an imperfection in one will be transferred to the second. If you use three and rotate which pair you're using, the imperfections cannot get transferred.


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## Cooler (Feb 3, 2016)

> Would it work to rub 2 sink cutouts face-to-face with some water and abrasive to grind them totally flat?
> 
> - splatman
> 
> ...


I've tried to smooth the edge of a granite tile. Marble will yield to sanding discs; granite will fight tooth and nail.

For ten dollars he can get a piece of double strength glass.


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## clin (Sep 3, 2015)

I bought a Grizzly Grade B (0.0001") surface plate from Amazon. It's smallish at 9" x 12" and was about $30. I wanted something I could move easily. At that price, not worth my time to scrounge up counter top scrap and hope it's flat.


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## Yacman23 (Sep 16, 2016)

Sooo sorry to leave you guys hanging! I'm new to the forum and dont know what I'm doing. Thanks for all of the great tips. Very helpful!


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## Tim457 (Jan 11, 2013)

> Would it work to rub 2 sink cutouts face-to-face with some water and abrasive to grind them totally flat?
> 
> - splatman
> 
> ...


You could use both sides of one piece to get the 3 needed surfaces. But I can't even imagine how much time it would take to lap by hand three granite surfaces together to get them flat. This is one of those things that unless the process sounds fun to you, it would take way more time than it would be worth. I was curious once how this was done though and found some detailed procedures online for the order of the surfaces to lap against each other and when to rotate one of the surfaces.


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## BillWhite (Jul 23, 2007)

I guess that I must weigh in on the absurdity of having a woodworking tool flattened to within .0005".
Wonder what our old fellows did? They got the item sharp, and used it. Chisel, plane, etc.
I do use a granite sink cut out. It works well. Did I check it to be sure that it was micron flat? NO!
I'll give ya sharp all day long with my surfaces and stones.
Bill


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## Skatergirl46 (Oct 6, 2016)

Cool idea! I have a granite slab that I use for leather working/tooling. That should work great. It's like the slab in the above listed add^ by tshiker. You can buy them at Tandy leather stores or online I believe also.


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