STRONGARM THUNDER BIT (1/4) - 9/32 X 4-1/4

Strongarm offers a line of high speed bits for drilling mild steel. Perfect for penetrating lock cases and precision drilling of key locks. The slight oversize of these bits help remove the shavings and drills run cooler. The diameter of this bit is 9/32".  That is 1/32 or 0.03158 inch larger than 1/4" to provide a bit of clearance befor changing to a carbide tipped or diamond tipped drill bit.