The standard TAPTITE PRO® fastener was designed with a 5-pitch stabilizing point (M6 & larger) that aligns the fastener very well and minimizes thread-forming torque in demanding applications. However, in aluminum and other non-ferrous applications the hole depth is quite often not as deep as desirable for an optimum joint.
This condition led to the development of shorter point TAPTITE PRO® SP™ screws. The shorter point of the TAPTITE PRO® SP™ fastener maximizes the amount of full thread engagement in blind holes. Increasing the full thread engagement is often critical in shallow depth holes. In many cases the failure mode can be shifted from internal thread stripping to fastener fracture, which is typically desirable in castings. In deeper holes, the shorter “SP” point may allow for a shorter length fastener, saving weight and cost.
TAPTITE PRO® SP™ fasteners are primarily used in aluminum and are therefore supplied with CORFLEX® N™ heat treatment to minimize the potential of stress corrosion. When used in steel material, TAPTITE PRO® SP™ fasteners can be ordered with case hardened or
CORFLEX® I™ heat treatment.
Questions & Answers Regarding TAPTITE PRO® SP™ Short Point Design Fasteners
Q. When should I use the “SP” version of TAPTITE PRO® fasteners?
A. The “SP” version can be used when the nut member size and shape has insufficient space for the standard TAPTITE PRO® design.
Q. Is there a downside to using the “SP” point, such as more difficult screw starting, cost or other?
A. This is an excellent question. For aluminum, the TAPTITE PRO® SP™ fastener is generally going to be the correct choice. However, if you have enough room to accommodate the longer stabilizing thread and point of the TAPTITE PRO® screw, that would be the better choice. The downside of the “SP” point is that it does not align as well.
Q. What are the comparative point lengths of the standard TAPTITE PRO® and TAPTITE PRO® SP™ designs?
A. Point lengths are as follows:
- TAPTITE PRO® SP™ fasteners
All sizes: 2½ pitches
- TAPTITE PRO® fasteners
M5 (#12) and smaller: 4 pitches
M6 (1/4”) and larger: 5 pitches
3 thread-forming threads
2 stabilizing threads that align the fastener (function as a dog point, but align the screw much better)
Q. If we go with stainless steel screws, do they automatically get a wax coating, or should we specify on our drawing?
A. Wax coating should be automatic, but we highly recommend you add it to the drawing to be sure.
Q. Is there a specification for the wax coating that we can reference?
A. There are a variety of waxes used in industry, so it is best to work out the specific wax for your application with your supplier. For quoting, we suggest stating a “water-soluble wax with UV tracer”.