Conventional Fasteners

Protocase stocks a wide variety of conventional fasteners, and if we don't stock it, we have access to just about any common fastener on a quick-delivery. The most commonly used items are machine screws and hex nuts, which are listed in the table below Self-tapping screws vs. machine screw / self-clinching nut combination In certain situations, a designer has the option of using either A) a combination of self clinching nut and machine screw, or B) a self-tapping screw, as shown in the diagram. We highly recommend option (A), for the following reasons:

• Self tapping screws are subject to stripping
• They interfere with finishes, breaking through powdercoating, and creating potential corrosion problems.
• Inconsistent removal torque --- they can lock in place, and be extremely difficult to remove.

The self tapping screw option is slightly less expensive, but the disadvantages far outweigh the slight savings for most applications. Thus the only place we would ever recommend Option (B) is when searching for cost-engineering solutions on volume orders.

 

Most Commonly Used Fasteners

Thread Size	length	Style	Finish
2-56	¼”	phillips pan head	zinc, black oxide, stainless
2-56	¼”	phillips flat head (82° & 100°)	zinc, black oxide, stainless
2-56	-	hex nut	zinc, stainless
4-40	¼”, 3/8”	phillips pan head	zinc, black oxide, stainless
4-40	¼”	phillips flat head (82° & 100°)	zinc, black oxide, stainless
4-40	-	hex nut	zinc, stainless
6-32	¼”, 3/8”	phillips pan head	zinc, black oxide, stainless
6-32	¼”, 3/8”	phillips flat head (82° & 100°)	zinc, black oxide, stainless
6-32	-	hex nut	zinc, black oxide, stainless
8-32	3/8”	phillips pan head	zinc, black oxide, stainless
8-32	3/8”	phillips flat head (82°)	zinc, black oxide, stainless
8-32	-	hex nut	zinc, black oxide, stainless
10-24	3/8”	phillips pan head	zinc
10-24	3/8”	phillips flat head (82°)	zinc
10-24	-	hex nut	zinc
10-32	3/8”	phillips pan head	zinc, stainless
10-32	3/8”	phillips flat head (82°)	zinc, stainless
10-32	-	hex nut	zinc, stainless
M3	6mm	phillips pan head	black oxide, stainless
M3	6mm	phillips flat head (90°)	stainless
M3	-	hex nut	zinc, stainless
M4	6mm	phillips pan head	black oxide, stainless
M4	6mm	phillips flat head (90°)	stainless
M4	-	hex nut	zinc, stainless
M5	10mm	phillips pan head	zinc
M5	10mm	phillips flat head (90°)	Stainless
M5	-	hex nut	zinc

The fasteners we use to assemble the enclosures are Machine Screws. We have a variety of sizes and finishes available - pdf.