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Spiral point tap 3/8-16 UNC three flutes black oxide finish

Greenfield Threading

Greenfield Threading 330120 Spiral Point Tap 3/8"-16 UNC 3 Flutes Steam

SKU CH-4DQE-0Y5G3

Cuts 3/8"-16 UNC threads in through-holes with a spiral-point design that pushes chips ahead of the tap

  • Spiral point drives chips forward for cleaner threads
  • 3/8"-16 UNC size fits standard coarse-thread applications
  • Three-flute design balances strength and chip clearance
  • High-speed steel with black oxide resists wear and corrosion
  • 75 % thread drill size .3125 in ensures accurate hole preparation

Application fit

The Greenfield Threading 330120 is a spiral point tap sized for 3/8"-16 UNC threads. It suits machinists and maintenance technicians who need to produce right-hand internal threads in through-holes. The H3 limit and 2B class of fit target standard industrial tolerance requirements. It is not intended for blind-hole work or left-hand threading.

Build and use

High-speed steel construction with a black oxide finish provides wear resistance during repeated cutting. The 3-flute spiral point geometry pushes chips ahead of the tap, reducing clogging in through-hole applications. A 2 15/16 in overall length and 1 1/4 in thread length give adequate reach for typical plate and bracket thicknesses. The 0.3125 in drill size prepares holes for approximately 75 percent thread engagement.

Included value

The tap is supplied as a single cutting tool ready for use with compatible tap holders or wrenches. No additional accessories, lubricants or software are bundled. Users must provide their own work-holding, cutting fluid and inspection gauges to complete the threading operation.

How it compares

Measured against everything we stock in Bits, Hole Saws & Accessory Kits, at today’s prices. Recalculated every night.

Price $7.99
Cheaper than about 91% of the 5,493 comparable items (median $27.99).

Specifications

Product
Brand nameCHICAGO-LATROBE

Questions about this item

What does the 3/8"-16 UNC thread size mean for hole preparation?

The 3/8"-16 UNC designation requires a 0.3125 in drill size for 75 percent thread engagement before tapping.

What are the physical dimensions for tool clearance?

Overall length is 2 15/16 in with a 1 1/4 in thread length, so ensure your holder and workpiece allow that reach.

How should this H3 limit tap be started to avoid cross-threading?

Apply steady axial pressure while keeping the tap perpendicular; the spiral point pushes chips forward but misalignment ruins the 2B class fit.

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