T-Slot Cutter Router Bit for 3/8-Inch Hex Bolt Heads 1/4-Inch Shank Hardened and tempered,carbon steel construction. Used for wood perforation,spherical door tip installation,drawer tip,plastic products,wood,plywood,etc..Trepanning more smooth,less noise. Sharp edge,high hardness,accurate positioning,high precision,smooth cutting,impact resistance,high toughness.Enable woodworkers to drill holes without passing through the material when a clean and precise bottom to a hole. Selection of high quality alloy blade,make blade more sharp and durable,it's head adopt arc curve design,beneficial to chip removal, perforation is more efficient. Suitable for hand held electric drill,stand motor-driven drilling machine and mobile ribbon type magnetism drilling machine