Metallics 5818CTT Carbon Steel Tap Taper Type 5/8-18 (1pc)

The Metallics 5818CTT cuts a 5/8-18 thread, meaning a 5/8 inch nominal diameter at 18 threads per inch. That is a fine-thread pitch rather than the coarse 5/8-11 you would get from a standard UNC tap, so match it to the fastener or rod you are threading for before you cut.

Taper type is the one to start with. The 5818CTT has a long chamfered lead that eases into a drilled hole and self-aligns, which is why it is the usual first tap for through-holes and hand tapping. If you need full threads to the bottom of a blind hole, you follow the taper with a plug and then a bottoming tap, which have progressively shorter leads.

Carbon steel. It is intended for hand tapping and repair work in mild steel and softer materials, at low speed with cutting oil. For production work or harder alloys, a high-speed steel tap holds an edge longer and tolerates powered tapping better.

Yes, provided the existing thread is genuinely 5/8-18 fine thread. A taper tap will chase and clean damaged female threads of a matching size and pitch. It will not recut a different pitch, so a 5/8-11 coarse hole needs a 5/8-11 tap instead, and electrical rod is commonly coarse thread.

The 5818CTT is the tap only. You will need a tap wrench or holder sized for its square drive, cutting oil, and a tap drill sized for 5/8-18 drilled before you thread. No wrench, drill, or lubricant is included.

One tap per pack, supplied in a pouch. If you are setting up multiple crews or want the full taper, plug and bottoming progression on the truck, order the quantity and sizes separately.

Order it as Metallics 5818CTT. The number reads directly off the spec: 5/8-18 thread, CTT for carbon steel taper tap. There is a single model on it, so no finish or size selection is needed.