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Greenfield Threading

Greenfield Threading 313583 Straight Flute Hand Tap Semi-Bottoming 3 pneumatic accessory

SKU CH-8NY7-EVK4A

A 5/16 inch UNF straight flute hand tap with semi-bottoming design for threading operations

  • Semi-bottoming design starts threads easily in through-holes
  • High-speed steel body resists wear during repeated tapping
  • Black oxide finish reduces friction and prevents galling
  • Three flutes clear chips efficiently for cleaner threads
  • Right-hand UNF 5/16-24 size fits standard fine-thread applications

Thread Size and Pitch

This CHICAGO-LATROBE hand tap cuts a 5/16 In. -24 UNF thread using a straight flute design. The semi-bottoming chamfer allows threading close to the bottom of a blind hole. It is made from high speed steel with a black oxide finish for corrosion resistance and wear life.

Build and Flute Geometry

The tap measures 2 23/32 in overall with a thread length of 1 1/8 in and features three flutes for chip evacuation. A right-hand thread direction and H11 thread limit produce a Class of Fit 1B result. The 75 percent thread drill size I prepares the correct hole for this specific geometry.

Application Limits

This tool is intended for hand tapping operations where machine rigidity is not available. The straight flute design works best in materials that produce broken chips rather than long strings. It does not suit deep holes beyond the stated thread length or high-volume production runs requiring spiral point or spiral flute evacuation.

Highlights

  • Semi-bottoming design starts threads easily in through-holes
  • High-speed steel body resists wear during repeated tapping
  • Black oxide finish reduces friction and prevents galling
  • Three flutes clear chips efficiently for cleaner threads
  • Right-hand UNF 5/16-24 size fits standard fine-thread applications

Specifications

BrandCHICAGO-LATROBE

Questions about this item

What thread standard and pitch does the 313583 tap cut?

It cuts a 5/16 in. -24 UNF thread with a Class 1B fit and H11 thread limit.

What drill size and shank dimensions are needed for this tap?

Use a number I drill for 75 percent thread; the tap has a 2 23/32 in. overall length and 1 1/8 in. thread length.

How do you start the tap correctly in a hand-tapping operation?

Apply cutting oil, align the tap squarely, turn two full revolutions forward then back half a turn to break chips; repeat until depth is reached.

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