Tap End Studs

A tap end stud is a type of double end stud. ASME B18.31.2 describes it as a stud made to be installed in a tapped hole, usually with a different thread length on each end. The short tap end is screwed into the tapped hole and stays there. The longer nut end passes through the mating part and takes the nut that clamps the joint.

Because the stud stays in the tapped hole, the joint can be taken apart by removing the nut, without wearing the threads in the casting each time. The tap end is commonly chamfered and the nut end rounded or chamfered, so the two ends can be told apart.

The tap end can be made with a standard Unified thread, or with a Class 5 interference-fit thread. A Class 5 tap end is made slightly oversize so it locks tightly in a matching tapped hole and resists backing out under vibration. ASME B18.31.2 refers to ASME B1.12 for these threads, in coarse thread sizes from 1/4 in. through 1-1/2 in. A Class 5 tap end needs a matching tapped hole in your part.

Tell us the thread class you need on each end, and we will confirm it before we make the parts.

To quote tap end studs, tell us:

• Diameter and thread for each end.
• Tap end thread length and thread class (standard or Class 5).
• Nut end thread length and the length of the unthreaded body.
• Overall length, measured end to end.
• Grade, coating and quantity.

If you send a drawing, we make the studs to it.

We make tap end studs in the stud grades we already make, including A193 B7, B7M, B16, A320 L7, B5, stainless and nickel alloys such as Inconel 625 and Inconel 718. Match the stud grade to the casting and the service, and compare options in our Fastener Materials Matrix.

What is a tap end stud?

A tap end stud is a stud with a short thread on one end that screws into a tapped hole and a longer thread on the other end for a nut. The middle of the stud is unthreaded.

What is the difference between a tap end stud and a double end stud?

Both are threaded on each end with a plain body. A clamping double end stud has the same thread on both ends and uses a nut on each end. A tap end stud is made to be installed in a tapped hole, usually with a shorter thread on the tap end.

What is a Class 5 tap end?

A Class 5 thread is an interference fit. The tap end is made slightly oversize so it grips the tapped hole tightly and resists loosening. It must be used with a matching tapped hole.

Which end goes into the hole?

The short tap end goes into the tapped hole. It is usually chamfered, while the nut end is usually rounded or chamfered so the ends can be told apart.