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Cleveland C27704 cobalt tap plug black oxide finish three flutes

Cleveland

Cleveland C27704 Spiral Point Tap Plug 3 Flutes UNC 3/8-16 Cobalt Black Oxide H3 pneumatic accessory

SKU CH-9YNM-3Q9RM

A cobalt spiral-point tap cuts 3/8-16 UNC threads in through-holes with three flutes and H3 limits

  • UNC 3/8-16 thread fits standard coarse fasteners
  • Spiral point design pushes chips forward for through-hole tapping
  • Cobalt steel with black oxide resists wear and heat
  • Three flutes give smooth cutting action and chip clearance
  • H3 limit and 2B class deliver accurate thread fit

Cleveland C27704 Spiral Point Tap

The Cleveland C27704 is a spiral point tap designed for through-hole threading in UNC 3/8-16 applications. It suits machinists and maintenance technicians who need reliable chip evacuation forward through the hole. The cobalt construction with black oxide finish provides wear resistance for general-purpose steel and alloy work. This tool is not for blind-hole threading where chips must be pulled upward.

Installation and common issues

The tap features a 3/4 inch thread length and an overall length of 2 15/16 inches with three flutes for stability. Use the specified 75 percent thread drill size of 0.3125 inches to prepare the hole correctly. Problems typically arise from incorrect drill sizing or insufficient lubrication, which can lead to oversized threads or tap breakage. Ensure alignment is maintained throughout the cut to avoid cross-threading.

Capacity and headroom

The H3 thread limit and Class of Fit 2B deliver standard tolerance for general fastening requirements. It comfortably handles production runs in mild to medium carbon steels where spiral point geometry excels at pushing chips ahead. The tool runs out of headroom in high-hardness materials exceeding its cobalt grade capability or in blind-hole depths beyond the thread length. Very high-volume production may require coated or carbide alternatives for extended life.

How it compares

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

Price $15.99
Cheaper than about 73% of the 5,493 comparable items (median $27.99).

Specifications

Product
Brand nameCLEVELAND

Questions about this item

How can I confirm the C27704 tap is cutting correctly after setup?

The tap should produce a clean 3/8-16 UNC thread with a 0.3125 in drill size, and the 3-flute spiral point will push chips forward through the hole for smooth operation.

What comes with the C27704 tap and what must I supply separately?

The package includes the cobalt spiral point tap plug with black oxide finish; you must provide a 0.3125 in drill bit and a compatible tap holder or wrench for the 3/8-16 UNC threading job.

Which version of the C27704 should I choose for my threading application?

The C27704 is offered in a single specification: 3/8-16 UNC, H3 limit, 3 flutes, 2 15/16 in overall length, 3/4 in thread length, cobalt with black oxide coating.

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