Hertel 66693524 Screw Machine Drill Bit Letter O Hss Tin

Product Description

The HERTEL 66693524 is a screw machine length drill bit designed for high-speed metal drilling in production and maintenance environments. Sized at Letter O (0.3160 inches decimal), it features a 135-degree split point that reduces walking on entry and requires no center punch on most metal surfaces. The bit is manufactured from high-speed steel (HSS) with a titanium nitride (TiN) coating that increases surface hardness and extends tool life in ferrous and non-ferrous materials. With an overall length of 2-15/16 inches and a flute length of 1-11/16 inches, this stub-length geometry increases rigidity and reduces deflection compared to jobber-length bits. Intended for use in drill presses, CNC machines, and hand-held power drills by machinists and maintenance technicians.

This bit is suited for screw machine operations, production drilling, and repair work where hole accuracy and tool rigidity matter. The straight cylindrical shank with a 0.3160-inch diameter fits standard drill chucks. The regular spiral flute and parallel web configuration support efficient chip evacuation in steels, aluminum, and other common shop materials. The heavy-duty grade and web-thinned geometry make it a practical choice for drilling in tight-tolerance work where stub-length bits outperform longer alternatives. It is sold individually and is appropriate for both shop and field use by qualified machinists and industrial maintenance personnel.

Key Features

• Letter O size (0.3160 inches decimal) with straight cylindrical shank of matching diameter
• 135-degree split point reduces entry walking and eliminates the need for center punching on most metals
• TiN coating improves surface hardness and extends cutting life compared to uncoated HSS
• Screw machine (stub) length at 2-15/16 inches overall increases rigidity and reduces deflection
• Web-thinned parallel web lowers thrust requirements and supports cleaner hole entry
• Right-hand cut with regular spiral flute for consistent chip evacuation

Compatibility

Designed as a direct-fit replacement or standard addition to any drill press, CNC machining center, or hand-held drill accepting a 0.3160-inch straight shank; part of the HERTEL HSH135-TN series of TiN-coated screw machine length drill bits.

Installation Notes

Install and remove drill bits only when the spindle is fully stopped and the machine is powered down or locked out per OSHA lockout/tagout procedures. Secure the straight shank firmly in the chuck and verify runout before drilling. Use appropriate cutting fluid for the material being drilled to maximize coating life and hole quality. Inspect the cutting edges for wear or chipping before each use; a damaged split point will produce oversized or off-location holes.