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Cleveland C55321 spiral point tap, gold TiN coated high speed steel, three flutes, plug style

Cleveland

Cleveland C55321 Spiral Point Tap 5/16-18 UNC HSS TiN 3 Flute

SKU CH-SDY2-GZT1V

Cuts 5/16-18 UNC threads in through-holes using high-speed steel with TiN coating and three flutes for efficient chip ejection

  • Spiral point design pushes chips forward for smoother threading
  • Titanium nitride coating reduces friction and extends cutting life
  • 5/16-18 UNC thread size matches standard fastener specifications
  • Three-flute geometry balances chip clearance with thread strength
  • High-speed steel construction withstands repeated use in production environments

Thread Cutting for 5/16-18 UNC

The Cleveland C55321 spiral point tap cuts internal threads for 5/16-18 UNC fasteners. It is designed for through-hole applications where chips are pushed forward ahead of the tool. The high speed steel body with TiN coating resists wear during repetitive threading operations. Suitable for maintenance and production environments requiring standard coarse threads.

High Speed Steel with TiN Coating

Three flutes provide chip clearance and cutting stability in a right-hand rotation. The plug chamfer engages the workpiece smoothly for consistent thread depth. Overall length measures 2 23/32 inches with a 1 1/8 inch thread length. The H3 limit and 2B class of fit match common inch-series specifications.

Through-Hole Optimised Geometry

Spiral point design evacuates chips forward, reducing binding in deep or continuous holes. Not intended for blind holes where chips must be lifted out. The 75 percent thread drill size F prepares the correct minor diameter for 2B fit. Users needing bottoming taps or left-hand threads must select different tooling.

How it compares

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

Price $16.99
Cheaper than about 70% of the 5,493 comparable items (median $27.99).

Specifications

Product
Brand nameCLEVELAND

Questions about this item

What thread standard does the 5/16-18 UNC tap follow, and what class of fit does it produce?

It follows the Unified National Coarse standard and produces a 2B class of fit for general-purpose threading.

What overall length and shank dimensions should I check for toolholder clearance?

The tap measures 2 23/32 inches overall with a 1 1/8 inch thread length; verify your holder accommodates this reach.

Which drill size should I use before tapping, and what common mistake should I avoid?

Use an F drill for 75 percent thread engagement; the frequent error is drilling the larger 5/16 inch clearance hole instead.

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