Osg 1011900 Straight Flute Tap 3-56 Unf Plug Hss

Product Description

The OSG 1011900 is a straight flute tap designed for threading 3-56 UNF holes in a range of ferrous and non-ferrous metals. Built from high-speed steel with a bright, uncoated finish, it cuts right-hand internal threads to a 2B class of fit and an H2 thread limit. The plug chamfer on this tap requires a through hole or sufficient chip clearance in a blind hole. With 3 flutes and a 1/2 inch thread length, it is sized for small-diameter threading applications where precision and fit consistency matter. Overall length is 1-13/16 inches, keeping it manageable in tight setups.

This tap is suited for threading aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. It fits residential and light industrial maintenance, toolroom work, and production setups where 3-56 UNF fastener threads are required. Machinists, tool and die technicians, and maintenance professionals use this tap in drill press, CNC, or hand-tapping operations where a standard straight flute geometry is the preferred choice for through-hole work.

Key Features

• 3-56 UNF thread form, 56 threads per inch, right-hand thread direction
• 2B class of fit with H2 thread limit for consistent, tolerance-controlled threads
• Plug chamfer for use in through holes or blind holes with adequate depth
• 3 straight flutes - no chip evacuation upward; best for through-hole applications
• High-speed steel construction handles a broad range of ferrous and non-ferrous workpiece materials
• Bright, uncoated finish - no additional surface treatment; suitable for use with standard tapping fluids

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces requiring a 3-56 UNF internal thread. Part of OSG Series 102.

Installation Notes

Straight flute taps are installed by machinists or maintenance technicians using a tap wrench, drill press, or CNC tapping cycle. Always ensure the pilot hole diameter matches the recommended tap drill size for 3-56 UNF before beginning the threading operation. Apply an appropriate tapping fluid for the workpiece material to reduce heat and extend tool life. Do not reverse-tap without breaking the chip first, and back off periodically to clear chips when working in deeper holes.