Metallics 5811CTB Carbon Steel Tap Bottoming Type 5/8-11 (1pc)

The Metallics 5811CTB cuts a 5/8-11 thread, meaning 5/8 inch nominal diameter at 11 threads per inch. That is the UNC coarse pitch for 5/8 inch, so it matches standard 5/8-11 rod, anchors, and bolts commonly used for hanging conduit racks, strut, and equipment supports.

A bottoming tap like the 5811CTB has almost no lead chamfer, so it cuts full-depth threads right to the bottom of a blind hole. It is not the tap you start a hole with. Start with a taper (plug) tap to get the thread going straight, then follow with the bottoming tap to finish the last few threads at the base. If your hole goes all the way through, a taper tap alone is usually all you need.

No. The 5811CTB is an inch UNC tap at 5/8-11 and will not cut or chase a metric thread such as M16x2. The diameters are close enough to seem interchangeable but the pitches are not, and forcing it will strip the hole. For metric work you need a metric tap in the matching size and pitch.

Carbon steel. The 5811CTB is a carbon steel hand tap, which suits field threading and chasing threads in mild steel, strut, and channel. For production drilling or harder alloys, an HSS tap holds its edge longer.

Yes, chasing out clogged or lightly damaged 5/8-11 threads is a normal use for it, and the bottoming grind lets you reach threads near the base of a blind insert that a taper tap would leave short. It is a hand tap, so turn it with a tap wrench and back it off regularly to clear chips.

For a 5/8-11 UNC thread the standard tap drill is 17/32 inch, which gives roughly 75 percent thread engagement. Drill the hole deeper than your required thread depth so chips have somewhere to go, then finish with the 5811CTB bottoming tap if the hole is blind.

One tap, supplied in a pouch. If you are stocking a van or a shop crib for 5/8-11 work, order the quantity you need, since each pack is a single piece.