Hertel 61699856 Screw Machine Drill Bit Letter R Hss

Product Description

The HERTEL 61699856 is a screw machine length drill bit sized to Letter R (0.3390 inches), designed for general-purpose drilling in metal, wood, and plastics. Built from high-speed steel (HSS) with an oxide coating, it offers improved lubricity and corrosion resistance compared to uncoated bits. The 118-degree standard point angle suits flat or moderately curved workpiece surfaces and allows the bit to self-center without a pilot hole on most materials. At 3 inches overall length, the screw machine format keeps the bit compact and rigid, reducing deflection in production environments. Machinists, tool-and-die shops, and maintenance technicians are the primary users.

Screw machine length bits are common in CNC drilling, turret lathes, and drill press applications where a shorter, stiffer tool is required. The 1-11/16 inch flute length accommodates moderate hole depths while the 3xD flute-to-diameter ratio provides adequate chip evacuation. Right-hand cut, straight-cylindrical shank fits standard three-jaw chucks and collet holders without adapter hardware. This bit is suited to short-run and high-volume production drilling where dimensional consistency at Letter R diameter is required.

Key Features

• Letter R diameter (0.3390 inches) with ANSI-compliant sizing
• 118-degree standard point angle for general-purpose entry on flat and curved surfaces
• High-speed steel construction for wear resistance across a broad range of workpiece materials
• Oxide coating improves surface lubricity and reduces heat buildup at the cutting edge
• Compact screw machine length (3 inches OAL) reduces deflection and improves rigidity
• Straight-cylindrical shank compatible with standard chucks and collet systems
• 2-flute regular spiral design for efficient chip evacuation in through and blind holes

Compatibility

Designed as a general-purpose screw machine length drill bit for use in standard three-jaw chucks, collet holders, and turret lathe tooling that accept a straight-cylindrical shank at the Letter R diameter range (0.3000 to 0.3500 inches).

Installation Notes

Installation and use should be performed by a qualified machinist or maintenance technician familiar with drilling operations. Secure the shank fully in the chuck or collet before operation and verify runout is within acceptable limits. Coolant-through is not supported on this bit; apply cutting fluid externally when drilling ferrous metals to manage heat. Follow applicable machine guarding and lockout/tagout procedures before changing tooling.