Accupro 4500380 Screw Machine Drill Bit 21/64 in Carbide

Product Description

The ACCUPRO 4500380 is a screw machine length drill bit designed for high-performance drilling in demanding metalworking applications. Built from solid carbide and coated with TiAlN (titanium aluminum nitride), this bit delivers extended tool life and thermal resistance under heavy cutting conditions. It carries a 140-degree web-thinned point angle optimized for accurate entry and reduced thrust force. The overall length is 3.937 inches, with a straight cylindrical shank diameter of 0.3438 inches and a right-hand spiral flute configuration. Two regular spiral flutes provide efficient chip evacuation. Coolant-through capability supports high-speed machining where through-spindle coolant is available. Machinists, tool-and-die technicians, and CNC operators are the primary installers of this bit.

This drill bit is engineered for stainless steels as the primary workpiece material, making it well suited for production machining, fabrication shops, and maintenance environments where hard-to-machine alloys are common. The screw machine length format offers a shorter, more rigid profile compared to jobber-length bits, reducing deflection in close-tolerance drilling operations. It fits standard straight-shank drill chucks and collet holders in both manual and CNC machine tools. The 3xD flute-to-diameter ratio and R-thinned web geometry support consistent, repeatable hole quality at the 0.3281-inch diameter range.

Key Features

• Solid carbide construction for rigidity and wear resistance in stainless steel and hard alloys
• TiAlN coating provides thermal resistance and extends cutting edge life at elevated temperatures
• 140-degree web-thinned point reduces entry thrust and improves centering accuracy
• Coolant-through design supports through-spindle coolant delivery for heat management
• Screw machine length body offers a shorter, stiffer profile that minimizes drill walk and deflection
• Right-hand cut with regular spiral flutes for efficient chip removal in ferrous materials

Compatibility

Designed as a direct-fit replacement for screw machine length drill bits with a 0.3438-inch straight cylindrical shank, compatible with standard drill chucks and collet systems accepting that shank diameter. Part of the ACCUPRO ASSC140-TA-CL series covering the 0.3000 to 0.3500 inch diameter range.

Installation Notes

Install and remove drill bits only with the machine powered down and the spindle fully stopped. Verify that the chuck or collet holder is rated for the shank diameter before securing the bit. Use appropriate cutting fluid or confirm through-coolant pressure settings before initiating cuts in stainless steel. Inspect the cutting edge and coating condition before each use, as carbide tooling can chip if impacted or dropped.