Coutertop cutouts for flat edge?

[AKnate]

I have 2 of these from a countertop place.

Quartz i think?

Are they worth hanging onto for use as a flat surface, like for measuring an engine head?

Obviously not going to be like a $5000 Starrett granite block, but better than concrete floor or plywood bench?

Small one in pic, other one is about 1.5x2ft. About 1.5" thick.

 

[Motorcharge]

Wouldn't think so. They'd probably make nice cutting boards though if you cleaned/polished them.

 

[Lbhsbz]

They're not made to any sort of flatness standards, so your results will vary.

Just get a good straight edge

 

[AKnate]

Wouldn't think so. They'd probably make nice cutting boards though if you cleaned/polished them.

Would kill blades I'd imagine. I use a $25 wood one for the few times a year I have to cut food.

 

[AKnate]

They're not made to any sort of flatness standards, so your results will vary.

Just get a good straight edge

Ok.

I've used glass and glued sandpaper to it for resurfacing small engine blocks and heads.

 

[subybaja]

Granite countertops do a pretty good impression of a surface plate. They're shiny enough you can use reflections to verify flatness.

I can't tell what that is- is it just as-cast, or is it flat polished?

I've got a small granite plate, but I've used 3/4" plate glass for bigger heads, and it worked fine.

 

[Lbhsbz]

Ok.

I've used glass and glued sandpaper to it for resurfacing small engine blocks and heads.

Glass flexes, and isn't flat at all (which you'll figure out if you ever check a piece of glass with a straight edge)

 

[rockmup]

They are fine for most things, I've used them before.

 

[arse_sidewards]

You can use ****ty glass and countertop remnants to sand **** flat but that's because of how the physics of sanding work. Heck, you can use ****ing plywood if you've got good technique and too much time on your hands.

You'd be a ****ing idiot to try to use something like that as a reference plane for measuring though.