Osg 1005200508 Straight Flute Tap 5/16-18 Unc Bottoming

Product Description

The OSG 1005200508 is a straight flute machine tap designed for cutting 5/16-18 UNC internal threads in a single pass. Built from powdered metal with a TiCN coating, it delivers extended tool life in demanding production environments. The bottoming chamfer geometry allows threading to the bottom of blind holes, making it the correct choice when full thread depth is required close to the hole floor. With 4 flutes and an H5 thread limit, this tap holds tight tolerances appropriate for 2B class of fit assemblies. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches.

This tap is suited for machine tapping operations in metalworking shops, maintenance facilities, and production environments. It is rated for use in aluminum and cast iron applications. Right-hand thread direction makes it compatible with standard tapping attachments and CNC rigid tapping setups. The bottoming chamfer designates it for blind-hole work where spiral-point or plug taps cannot achieve full thread engagement. Series 10052 places it within OSG's standard machine tap line.

Key Features

• Bottoming chamfer for threading to the base of blind holes
• Powdered metal construction for improved wear resistance over standard HSS
• TiCN coating reduces friction and extends tool life in aluminum and cast iron
• 4 flutes with H5 thread limit for consistent 2B class of fit tolerances
• Right-hand, 5/16-18 UNC thread form for standard inch fastener applications
• No coolant-through design — compatible with external flood or mist coolant delivery

Compatibility

Designed for machine tapping 5/16-18 UNC threads in aluminum and cast iron workpieces. Compatible with standard straight-shank tapping chucks, floating tap holders, and CNC rigid tapping setups that accept the specified shank diameter of 0.318 inches.

Installation Notes

Installation and operation should be performed by a qualified machinist or tooling technician familiar with tapping speeds and feeds for the workpiece material. Ensure the spindle is stopped and the machine is in a safe state before loading or removing the tap from the holder. Use appropriate cutting fluid or coolant for the material being tapped — aluminum and cast iron have different lubrication requirements. Inspect the tap for chipping or wear before each use; a bottoming tap operated in a hole with insufficient chip clearance is prone to breakage.