4 Pcs Carbide Rotary Burr Set, 1/4-Inch Long Shank Tungsten Steel Head Burr Bit Set Fits Rotary Tool for Wood/Metal Drilling Carving Engraving

I used this on a set of cheap knock off Chinese split manifold headers. Worked out ok ,but I knew better to buy set of cheap Chinese headers.

Shipped fast

Works great and price was good

Just like all the other reviews: -terrible runout, not usable. Even with RPMs turned down below 8K -shafts are too soft. with the initial runout so bad, the shafts bend immediately -even the 'best' one had far too much chatter when grinding, totally unusable. -shaft size is not 1/4" but is 6mm, which is less. worked OK with my collets but I can see the problem with others -I re-installed quality ones I already had and it was like reaffirmation of parts quality, perfect balance and cutting. *Do not buy these, I can't imagine them working for anyone. even if you turn your tool speed down below 5K. (typical air grinders are 20K). may only be useful for wood workers and very very slow tool speeds.

Be cautious of rpm. These all failed pretty quickly at 25k. I have used a speed control Since with higher cost burrs with success. The long burrs are pretty picky about wobble and will quickly bend permanently or come apart. They were probably worth the $20 for the four of them, but I can get quality burrs for $20 each that last longer and cut better.

Great

They cut. They are hard to control in a die grinder so I used a drill. Used them on a cylinder head. The heads look like they are brazed on but none came off or bent. They are about the same quality as something stamped Pittsburgh, but worked good for what I needed. I would buy again.

Great tools, used them on a 5.9l Cummins 24valve, once I finished there is still life in them, probably handle another head or a v8 pair! I recommend these, they did good for me.