Metallics JFSCZ1434 Screw 1/4-20 x 3/4 SHCS FH St-Zn (Jar 100)

The Metallics JFSCZ1434 is a 1/4-20 x 3/4 inch socket head cap screw, flat head, in zinc-plated steel. The 1/4-20 means a quarter inch nominal diameter with 20 threads per inch, which is the standard UNC coarse thread for that diameter, so it mates with 1/4-20 nuts and tapped 1/4-20 holes.

Flat head. The JFSCZ1434 is a flat head socket cap screw, so it needs a countersunk hole and sits flush with the surface rather than standing proud like a standard cylindrical-head SHCS. If your hole is not countersunk, a flat head will not seat properly and you want a standard socket head cap screw instead.

100 screws per jar. Metallics packages the JFSCZ1434 in jar form, which is how it ships for shop and service-truck stock rather than loose count or bulk box.

Zinc plating on the JFSCZ1434 is a sacrificial coating for indoor and dry-location corrosion resistance. It holds up in conditioned interiors, enclosures, and panel work, but in wet, coastal, or chemically aggressive locations plated carbon steel will eventually rust at the plating breaks. For sustained exposure, specify a stainless fastener in the same 1/4-20 x 3/4 size instead.

The 3/4 inch length on the JFSCZ1434 is measured from the underside of the surface for a flat head, because a countersunk head sinks into the material. That means total grip is 3/4 inch of material plus thread engagement, so it suits thin plate, strut fittings, enclosure brackets, and sheet steel assemblies. For thicker stacks you need a longer 1/4-20 in the same series.

Order Metallics part number JFSCZ1434. That designation covers the 1/4-20 x 3/4 inch flat head socket cap screw in zinc-plated steel, packed 100 to a jar. There is one configuration under that number, so there is no finish or length option to specify.

A 1/4-20 flat head socket cap screw takes a hex (Allen) key, not a screwdriver, driven from the internal socket in the countersunk head. The JFSCZ1434 is the 3/4 inch length in that size. Hex drive is what lets you torque it down in a recessed hole where a bit driver would cam out.

It is stocked as electrical fastener hardware, which is where 1/4-20 machine screws get used most: enclosure and panel mounting, strut and channel fittings, ground bar and busbar hardware, and fixture brackets. The thread and head are standard, so nothing about it is electrical-specific, and it works anywhere a 1/4-20 flat head socket screw is called out.