Sumitomo U101178 Screw Machine Drill Bit 0.4688 in

Product Description

The SUMITOMO U101178 is a solid carbide screw machine length drill bit designed for high-precision drilling in demanding production environments. With a 0.4688-inch (15/32 inch) diameter and a 135-degree split-point angle, it delivers accurate hole entry and reduced thrust force on hard materials. The straight-cylindrical shank provides a secure, concentric grip in standard drill chucks and collets. Two flutes with a tapered web configuration evacuate chips efficiently and maintain cutting edge stability throughout the bore. This bit is intended for machinists, toolroom technicians, and production shop operators working with ferrous and cast materials.

The U101178 belongs to the MDW-GS series and is suited for screw machine and CNC drilling operations in cast iron and steel workpieces. The screw machine length format — shorter overall length compared to jobber bits — provides added rigidity and reduces deflection when drilling at production feed rates. It is a practical selection for high-volume hole-making tasks where dimensional consistency and tool life are priorities in a shop or automated machining cell.

Key Features

• Solid carbide construction for hardness and wear resistance in ferrous materials
• 135-degree drill point angle reduces entry thrust and self-centers on the workpiece
• Screw machine length (3.9370 inches overall) provides superior rigidity over jobber-length bits
• Tapered web configuration supports chip clearance and cutting edge strength
• Straight-cylindrical shank compatible with standard collets and drill chucks
• Diameter tolerance h8 for consistent, repeatable hole sizing

Compatibility

Designed as a screw machine length replacement drill bit for use in CNC machining centers, screw machines, and drill presses working with cast iron and steel. Suitable for applications within the 0.4500 to 0.5000-inch drill bit size range.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician. Ensure the spindle is fully stopped and the machine is locked out before changing tooling. Seat the straight-cylindrical shank fully into the collet or chuck and verify runout before drilling. Do not exceed the maximum drilling depth of 1.1470 inches per pass without retracting to clear chips, as this bit does not feature coolant-through capability.