YUFUTOLCarbide Burrs Set - 5pcs diameter Extended Long Double Cut Solid Carbide Rotary Burr File Set 1/4 Inch Shank for Die Grinder Drill, Metal Carving,Polishing,Engraving,Drilling

These little guys cut !I have broken the shaft off a couple but only cause I was horsing them.Useful .

These are worth the money. So far I've done one complete head and a throttle body, and started a second head. They are still sharp and cutting well. The one I use the most has a few small chips on the rounded part, but still works perfectly. I'd definitely buy again. I've been using on aluminum and I've been putting small dabs of grease on it to help keep it from gumming up as bad.

I used these to grind on aluminum intake manifold ports. I thought they cut well, left a reasonably decent surface. They did not clog with aluminum at all, even dry. Can't comment on durability, but after maybe 30 minutes of grind time, I see no signs of wear or reduced cutting performance.

I purchased this item for porting work. I haven’t used them yet but they look good and feel confident that they will do the job.

These are long and sharp, they perform great. I only used them on Aluminum so can't speak for other metals.

Unsure about durability but out of the box they work well for the cost

Using them to port an aluminum head. They work well. Keep them lubed and they don't gum up. Chattering is controlled by tool speed. Very pleased with them.

Good sharp tool set,I use it for hard metals not stainless steel though and aluminum..if you carve aluminum use a slow speed or you will melt the aluminum to the tool or clog up the teeth