Metallics JSHC343 3/4-10 x 3 in. Socket Head Hex Cap Screws - Alloy Steel Black - Each

Yes. The Metallics JSHC343 is a 3/4-10 UN thread, 10 threads per inch, which is standard 3/4 inch coarse (UNC). It drops into any 3/4-10 tapped hole, insert, or nut. Thread length aside, overall screw length is 3 inches.

Head height runs 0.74 to 0.75 inch and head width (across the cylindrical head) runs 1.107 to 1.125 inch, so a counterbore needs to be at least 1-1/8 inch diameter and about 3/4 inch deep to bring the head flush. That is the advantage of a socket head over a hex head here: it is internally wrenched, so you do not need clearance around the head for a wrench.

In this case yes. The alloy steel socket head cap screw is rated 170,000 psi minimum tensile and 162,000 psi minimum yield, which is above equivalent-size Grade 5 or Grade 8 hex head cap screws, and it does it in less surface area because the drive is internal. Hardness is Rockwell C39. If your joint is tight on space or you need higher clamp load at 3/4 inch, this is the screw to use over a hex bolt.

No. The JSHC343 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If the job carries a domestic-content clause, these will not qualify.

It takes a hex key (Allen), not Torx. The head is a socket head with a hex internal drive, and socket depth is 0.37 inch, so use a full-length hex key or a hex bit socket seated fully to avoid rounding the socket out at these torque levels.

They are built to ASME B18.3-2012, the dimensional standard for socket cap screws, so head and socket geometry will match any drawing or submittal calling out B18.3. Useful if you are standardizing fasteners across a facility and need the counterbore detail to stay consistent.

Minimum order is 25 each, supplied in a jar. Other sizes and quantities are available by request.

The finish here is plain black alloy steel with no plating called out, so treat it as an indoor or protected-location fastener. Black oxide style alloy screws are not a corrosion finish. For exterior strut, rooftop equipment, or damp mechanical rooms, specify a zinc plated or stainless fastener instead.

At 3 inches long on a 3/4 inch diameter the screw is well past 3D, and cap screws of 3D or greater length are subject to tensile strength, yield strength, elongation, and reduction of area testing. Elongation is 10 percent minimum and reduction of area is 33 percent minimum on machined specimens. So the 170,000 psi tensile figure is a tested property, not just a dimensional callout.

They are specified for electrical, plumbing, and heating and air conditioning work, anchoring and machine-bolting applications where you need high clamp load in a counterbored or tight-clearance joint. Typical use is bolting equipment bases, mounting brackets, and structural steel attachments where a hex head would not have wrench clearance.

The packaged jar is listed at 4.89 lbs. That is the full order quantity of 25, so plan handling accordingly if you are ordering several jars for a large bolt-up.