Cleveland C59421 Thread Forming Tap M3x0.50 6H Bottoming Hss

Product Description

The CLEVELAND C59421 is a bottoming-style thread forming tap designed for creating M3x0.50 metric coarse internal threads in blind holes. Manufactured from high-speed steel (HSS) with a bright, uncoated finish, this tap cold-forms threads rather than cutting them, resulting in stronger thread profiles with no chips to evacuate. It carries a 6H class of fit and a D5 thread limit, making it suitable for precision threading applications where consistent tolerance control is required. Overall length is 1.938 inches with a thread length of 0.625 inches and a shank diameter of 0.141 inches. It is part of Cleveland Series 1092 and is intended for installation by machinists, tool and die makers, and maintenance technicians.

The C59421 is suited for blind hole threading in steel, stainless steel, and non-ferrous metals. Its 1-2 thread chamfer length is characteristic of a bottoming tap, allowing threads to be formed as close to the bottom of a blind hole as possible. This makes it particularly useful in precision machining, fixture fabrication, and equipment repair where full thread depth in shallow blind holes is critical. Right-hand thread direction follows standard metric fastener conventions.

Key Features

• Bottoming chamfer with 1-2 thread lead for threading close to the bottom of blind holes
• Thread forming design eliminates chips, reducing clogging risk in blind hole applications
• High-speed steel construction provides wear resistance across a range of workpiece materials
• 6H class of fit with D5 thread limit for repeatable tolerance control
• Compatible with steel, stainless steel, and non-ferrous metal workpieces
• Bright, uncoated finish suitable for use with standard tapping fluids

Compatibility

Designed for M3x0.50 metric coarse blind hole threading applications in steel, stainless steel, and non-ferrous metals where a bottoming tap geometry and 6H tolerance class are specified.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which differs from a standard cut tap drill — consult a metric thread forming tap drill chart before use. Apply appropriate tapping fluid or cutting oil for the workpiece material; dry threading is not recommended for HSS taps. Secure the workpiece firmly and use a calibrated tap handle or tapping attachment to maintain axial alignment and avoid tap breakage. Always relieve torque and back out the tap periodically if resistance increases.