Yakamoz 10Pcs 3mm (1/8") Shank Long Double Cut Tungsten Carbide Burrs Rotary Files Diamond Burs Bit Set for Die Grinder Rotary Tool, 4-Inch Length

I bought these for a very specific application. To grind out the RSA channel on P940 80% frames. This area of the frame is particularly hard to get perfect. Tough to sand effectively and you can’t get a conventional dremel bit in there. The 4” shaft length is long enough to even do the P940CL.I highly recommend these, wish I would have found them many frames ago.

Very good !!! Recommend!!!!

Chucked these up un my pneumatic 1/8" pencil style mini grinder. They're definitely not prepared to handle 20k rpm, however, I learned a trick to get them working okayish even with a slight to moderate degree of "out of balanceness."Essentially, if I start the pencil style grinder out on a slower speed, and then apply the deburring surface to what I'm grinding on, I can then increase the rpm without the wobble, then slow it back down before removing from the work surface.A bit of a pain to work with like that, but I was able to get them to work for what I needed without damage to anything. Ended up working out alright, albeit not ideal.For the price, I have no regerts

These are great for reaching into a transfer port on a chainsaw cylinder... they work pretty good and they last pretty good too. I’ve got no complaints...

they vibrate badly, unusable, was going to return them but found they only shipped me nine not ten, so they will probably not take it back, as one is missing, I am going to cut the shafts shorter so maybe will not vibrate as much,

These bits looks nice out of the box, and appear to have sharp cutting edges, but they dull very quickly when used on metal. These bits are more suited for use with wood or plastic than metal. On the plus side, you get a lot of them, so between all of the bits you may be able to finish your project. In order for these bits to be effective, they need to be harder than the metals they are used with. Just OK.

Work well for porting small cylinder heads

I'm porting two cylinder hands and I said ehh I'll try. Something different. These bits are straight as an arrow and the double cuts preventing any debris build up. I hands down impressed.