YUFUTOL SF-5L6 Tungsten Carbide Burr - 6” (152.4mm) Long Double Cut Carbide Burr File (1/2” cutter Dia X 1”Cutter Length) with 1/4 shank dia Tree Shape Radius End,1pcs

You should not spin grinding bits at maxt rpm, they work better when you turn down the speed of your 15,000 rpm capable rotory tool. Save the max rpm for cut-off wheels or sanding.I needed this to grind a weld smooth in a hard to reach area, it worked like it should. Just let the tool do the work.

Product is as described and performs flawlessly, shipping was fast and customer service was great. will definitely buy again.

Very awesome and design cuts through metal like butter makes quick work of burrs and imperfection.

I used this on cast iron (an engine block) to smooth out holes that were drilled and contour one end-hole into more of a spout shape. This bit worked both well and quickly. I used a Ryobi hand drill for the task and it only goes up to 1800 rpm, so the other reviews regarding high-speed shenanigans did not apply in my case. Given that I had seen the other reviews, I also kept a finger on the shaft to support it while drilling, in hopes of preventing it from bending out of shape.

Heavy duty! I used this bit to grind the frame inside the engine bay of my blazer to reach a bolt that GM his during manufacturing. Worked perfectly!

I needed this to remove some wood glued with epoxy in a hard to reach tail section of a giant scale radio control airplane.

Cuts real good

Nice sharp carbide burr for the money. The long shaft is great for cleaning up cylinder heads and reaching way down in the runners.