Self-piercing screws, also commonly known as zip screws, are self-tapping in that they tap their own threads. They are also sometimes referred to as needlepoint screws because they will ‘self start’ with soft metals when pressure is applied. Our experience has been that the #8 x1/2 Hex Washer Head Needlepoint screws (zip screws) have reportedly worked best when used in square duct with 30 and 28 gauge metals. Contractors have stated that they have better luck with #7 needlepoints when doing round pipe with 24 and 26 gauge metals. Application is very important when choosing what screw to use in your job, otherwise, the fasteners may not perform in the way that you expected them to perform. Many fastener ‘failures’ are actually using the wrong part for the job. Although some have said that they have been able to use #7 zip screws in up to 20 gauge metals, we have been told that when working with metal 22 gauges and thicker, tek screw type screws really do the job much easier.
Self-piercing screws (zip screws) are popular with the Heating and Air Conditioning and the gutter industry. 8x 1 ½ or 8×2 Hex Washer Head Zip Screws painted white are frequently purchased for the registers. The gutter industry use mainly painted 8×1/2 hex washer head needlepoints and 10×1 1/2 Hex Washer Head Needlepoints (zip screws) although copper plated stainless steel zip screws are becoming much more popular and we are one of the few companies that supply them!