Value Collection MSC-04919361 Straight Flute Tap 1-1/8-12 Unf

Product Description

The VALUE COLLECTION MSC-04919361 is a straight flute bottoming tap designed for cutting 1-1/8-12 UNF internal threads in a left-hand direction. Manufactured from high-speed steel with a bright/uncoated finish, this tap delivers reliable thread-cutting performance in ferrous and non-ferrous materials. With 4 flutes and a bottoming chamfer, it is suited for threading blind holes where full thread depth close to the bottom of the bore is required. The H4 thread limit designation indicates the tolerance range applied to the tap geometry, ensuring threads meet 3B class of fit standards. Machinists, toolroom technicians, and maintenance professionals use this tap in manual or CNC tapping operations.

This tap is applied in machining and maintenance scenarios where a left-hand 1-1/8-12 UNF thread is specified. Left-hand threads are commonly found on rotating assemblies, specialty fastener applications, and components where counterclockwise torque would otherwise loosen a standard right-hand fastener. The bottoming chamfer makes this tap the final step in a three-tap sequence after a taper and plug tap have been used to open and advance the thread, allowing full threads to be cut close to the bottom of a blind hole. It is appropriate for bench work, drill press setups, and CNC tapping centers.

Key Features

• Bottoming chamfer enables full thread depth in blind holes
• Left-hand thread direction for specialty rotating or anti-loosening applications
• 4 straight flutes for chip clearance in through and blind hole tapping
• High-speed steel construction provides hardness and wear resistance across a range of workpiece materials
• 3B class of fit with H4 thread limit for consistent, tolerance-controlled threads
• Bright/uncoated finish suitable for general-purpose tapping with appropriate cutting fluid

Compatibility

Designed for cutting 1-1/8-12 UNF left-hand internal threads. Compatible with standard tap holders and tapping attachments sized for the tap shank. Intended for use as a bottoming tap following taper and plug tap operations in a standard three-tap sequence.

Installation Notes

This tap should be installed by a qualified machinist or toolroom technician familiar with threading operations. Secure the workpiece firmly before tapping and ensure the tap is properly aligned perpendicular to the workpiece surface to avoid tap breakage or cross-threading. Apply an appropriate cutting fluid for the workpiece material throughout the tapping operation. When used in a blind hole, clear chips frequently to prevent packing and potential tap breakage.