2Pcs 1/4'' Shank Straight Brazed Diamond Profile Wheel Router Bit for Marble Granite Stone Hells Tile Edge Electric Router Profiling Cutting (2Pcs 1/4'' Shank)

Did the job

Work well for enlarging and hole

Good quality

Did the job that we needed to be done

It looks pretty but it does not cut tile

Diamonds wore off in a foot or two.

Very poor quality diamond bit. The bit is course grade with a maximum grain size of about .02 inch or .5 mm. The area density of the diamonds is very low, about 20% of the total coated area. The diamond grains vary greatly in size, from .02 to .005 inch (.5 mm to .1 mm). This leaves an extremely small amount of cutting surface area as the bit rotates. The larger grains simply get knocked off, which leaves even fewer cutting edges. The microscope images are of a new bit (still fully electroplated) and a bit used for a few minutes. The gray areas in the used bit are where the taller diamond grains got knocked off. Notice that over half of the grains in the used bit are still electroplated because they are too short to come into contact. The nickel colored flat image is a course grade sharpener for comparison of grain density.

I'm cutting my own granite counter tops from prefab granite slabs. I use other tools to cut and grind everything down. I then used these bits to straighten up the edges using a 2hp router with a 1/2 inch collet and a straight edge clamped to the granite. Very comparable to sanding wood with 80 grit sandpaper. This does not cut like a router bit.