Wolfride 4pcs Long Shank Tungsten Carbide Burr Set 6mm Shank Die Grinder Burr Set for Metal 6-Inch Length

They're well made, and they survived a lot of use recently. I highly recommend!

I am making this review to hopefully answer the questions I had before I purchased these that I found only vague answers to.I used these bits to port 460 (7.5L) Ford cast iron cylinder heads, I matched both the intake and exhaust ports to the gaskets and removed a large cast iron "bump" in the exhaust port to hopefully create a little more horsepower. These bits worked excellent for my intended purpose and they didn't create a lot of heat. All total I did 8 intake ports, 8 exhaust ports and 8 intake manifold ports plus once I was done doing the serious work I decided to take off the casting boogers and mold flange marks from when the engine was made since it was out of the car. These bits worked all the way to the end, if I had to guess I would imagine they would do a few more engines before becoming dull.One thing I should mention The bits are I am pretty sure metric in their diameter (6mm) where a typical collet is (6.21mm) ¼" the collet on my air die grinder tightened up ok but when I went back to use a quarter inch shank bit I had to use a tiny screwdriver to open the collet back up. It wasn't a big deal but it is something to be aware of.Now for some Captain obvious thingsWear googles, the cast iron "chips" are not sharp but they really fly out and sometimes they end up in your face and also I would recommend a face mask so you don't inhale them to quote my mother "you only get one set of lungs".Anyways I hope this helps... Oh and the bits are about 6" long (150ish MM) for anyone wondering.

Buen producto me gustaron es el temaño que yo quería

They hold shape on heavy-duty, stay sharp, and the size is very helpful

works great in a drill. when used in an electric die grinder, the lack in thickness allows flex and a lot of wobble in the bit. to cut down on wobble, a couple of inches will need to removed if prefer to use in die grinder.

Did the job but one broke as soon as it hit the metal. Got me out of a bind though

l only used the round bit to grind off two screws that was securing the a/c expansion valve which stripped, i spent time and money on other extraction bits that did not work. i was able to accomplish the task in less than 10 minutes of grinding! The bit held up and would purchase again.

I needed the longer shaft ones and these mostly did the job grinding out a hardened metal rod shaft that was stuck in a bolt hole.