Can I use a traditional router bit on a small concrete slab? And if no what can I use? I'm getting ready to make a coffee table. I know the trick where you put silicone in the corners to achieve a bevel but I want to add a few fossils or some petrified wood and Im going to need to sand the corners of that down because I want it in the corner of the table if possible just like this pic:

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I'm mounting this top on a coffee table so it most likely will just be a slab that will lay flat on top of the table I built. I was thinking of clamping the top to the base so I can get in there and grind it to fit perfectly then unclamp. Then polish it. The weight should keep it from sliding around I would imagine

  • If you haven't cast the table yet, the best option is to place your corner items in the form first and let the concrete form around it. In the picture that is an engineered material (think corian) that was cast in a form with the item placed in the form. There is no way you can precisely grind out a complex shape like that.
    – diceless
    Commented Oct 16, 2014 at 15:25
  • Fossils/petrified wood are all mineral based and will require rock tools (think granite) to work with. So, if the picture above is concrete with a piece of petrified wood embedded into it, you'll still need to use the tools used for granite. FYI. granite is harder then concrete so anything you get for granite will work for concrete. Commented Nov 2, 2017 at 12:48

1 Answer 1


Quick answer.... NO.

You will need to get bits designed for concrete. Concrete is very abrasive and will destroy a wood bit in microseconds and not do much of anything to the concrete.

  • 3
    I think it will take at least 2 milliseconds to destroy the bit. 30,000 rpm (on the high side but sometimes seen) / 60 seconds - 500 revolutions per second, so 2 milliseconds per revolution. ;^)
    – Ecnerwal
    Commented Oct 15, 2014 at 21:57
  • 3
    Think diamond or some such if it's granite or other stone. And lots of water. For concrete countertops, you actually mold the edge in by using a proper form, that's the joy of doing a proper job casting, then you polish it. Commented Oct 16, 2014 at 2:15
  • Ok so heres what I have. I welded up a table thats not 100% square. The metal warped slightly so its off about a 16th of an inch maybe slightly more. Whats the best way to sand that off once I have mounted the top if I cant use conventional sanding pads? I want the concrete to be flush with the steel. I just bought a wet grinder but I am new to this stuff. Commented Oct 26, 2014 at 15:35
  • @JohnDangerous, how to you plan on mounting the top to the frame? If you plan on clamping/screwing the frame to the top, the frame should flex enough to give a flush connection.
    – diceless
    Commented Oct 27, 2014 at 4:17

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