Advanced Carbide MaterialThe rotary burrs are made of Tungsten Carbide, which is sharp and sturdy. And the hardness can reach to HRC70. The durability of carbide burr is 10 times higher than high speed steel cutter (HSS cutter). 200 times more than the small wheel durability. Comprehensive processing costs can be reduced by about 10 times. Double Cut or Single CutDouble cut burr have more cutting edges and could remove material much faster. It is more suitable for relatively low density materials such as wood, plastic, aluminum, soft steel and all non-metal materials. Single cut burr provides large, wide flutes evacuate the large chips easily and also prevent iron-chip accumulate and over-heat cause cutter head damage. It is more suitable for relatively high density materials such as iron, alloy steel, stainless steel etc. Professsion 20 PCS SetThe carving bits include A, C, D, E, F, G, H, L, M and N type burrs. There are 2 sizes for each type burrs, which is 1/8 shank 1/8 head diameter and 1/8 shank 1/4 head diameter. They are suitable for almost everything you need for engraving, cutting, shaping, grinding, polishing and removing sharp edges. Easy to Use If the cutting bits are chipping easily this could be due to the speed being too slow. However, it's ideal to start the cutting slow, increasing the speed as you go along. High speeds will prevent clogging in the flutes of your burrs. The 1/8 carving burrs can bear the speed range of 6000-50000 revolutions per minute. Widly UseThe 3mm and 6mm head diameter carbide burr set is widely used for metalwork, tool making, model engineering, wood carving, jewelry making,welding, chamfering, casting, deburring, grinding, cylinder head porting and sculpting.