Cleveland C54789 Straight Flute Hand Tap 5/8"-18 UNF

Cleveland C54789 Hand Tap for UNF Threading

The Cleveland C54789 is a straight-flute hand tap designed to cut 5/8"-18 UNF threads in through-holes or blind holes. It is made from high-speed steel with a bright, uncoated finish for general-purpose threading in ferrous and non-ferrous materials. The right-hand cut and H3 thread limit produce a class 2B fit. Machinists and maintenance technicians use it for repair work or short-run production where machine tapping is not practical.

Manual Operation Limits Chip Evacuation

Straight-flute geometry relies on the operator to reverse the tap frequently to break and clear chips, especially at the full 1.81 in thread length. The 75 percent thread drill size of 14.50 mm leaves minimal clearance for swarf in deep blind holes. Bottoming chamfer cuts threads close to the bottom but requires a pre-drilled hole deeper than the 3.81 in overall length. Hand tapping cannot match the speed or consistency of a powered tapping head.

5/8"-18 UNF Size Determines Fit

This tap cuts only 5/8"-18 UNF threads with an H3 limit for a class 2B fit. It will not produce metric, coarse UNC, or any other thread form or diameter. Select a different tap if the drawing calls for a different pitch, diameter, or class of fit. The H3 limit is not interchangeable with H1, H2, or higher limits without changing the resulting thread tolerance.