Use the 4-40 x 3 1/2 18-8 stainless hex head cap screw when the assembly calls for side wrench access and a general-purpose bolt pattern. In this size range it is treated as a hex head machine screw, with the hex head driven by external tooling rather than an internal socket.

Common application reviews include machine bases, structural brackets, and tapped-hole fastening points. The head can be tightened with standard side-access tooling, which helps where top clearance is limited by covers or nearby components.

18-8 stainless steel is an 18% chromium and 8% nickel austenitic stainless material used for ordinary atmosphere, moisture exposure, washdown, and clean appearance. Cold Headers helps buyers match uncommon lengths, older drawings, and replacement sizes without changing the protected SKU data.

Technical Highlights

• Material: 18-8 Stainless Steel
• Thread Size: 4-40
• Length: 3 1/2 in.
• Head Style: Hex
• Drive: External Hex (wrench or socket driven)

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.