MS51975 socket head shoulder screws
Alloy steel shoulder screws (stripper bolts) with a hex socket head, shoulder diameters 1/4 through 1-1/4 in., UNC-3A thread.
MS51975, machined to the standard.
MS51975 is the socket head shoulder screw: a ground shoulder for locating or pivoting, with a UNC-3A thread one size smaller than the shoulder. The sheet calls for alloy steel per MIL-S-21472 (now NASM21472), cadmium plated. It was cancelled in 1998 and is now NASM51975 with part numbers unchanged; the NASM title adds nonferrous alloys.
- Machined from certified bar to the standard; no hot heading
- AS9100D and ISO 9001:2015 quality system; CAGE 8HH90
- DFARS-compliant material available on request
- No minimum quantity; prototype through production
- Material test reports and certificates of conformance with the order
Send the full part number with the dash number and code letters, the quantity, the required delivery and the documentation your purchase order calls for.
MS51975 at a glance
| Detail | Specification |
|---|---|
| Standard | MS51975, now NASM51975 (active) |
| Title | Screw, Shoulder, Socket Head, Hexagon, Alloy Steel, Cadmium Plated, UNC-3A |
| Material | Alloy steel per NASM21472, cadmium plated |
| Thread | UNC-3A; shoulder .250 through 1.250 with threads #10-24 through 7/8-9 |
| Strength | Sheet: 140,000 psi minimum tensile on the thread neck area |
| Typical use | Pivot, locating and stripper applications in machinery and tooling |
Part numbers covered: MS51975-1 through MS51975-81. Reference only; the current revision of the standard on your order governs.
Reading the part number.
| Element | Meaning |
|---|---|
| Dash number | Shoulder diameter and shoulder length from Table II |
How Cyclone makes them
Bar stock certified to the material specification is cut, turned and threaded to the standard’s dimensions, with drilled heads or shanks and head markings as the part number requires. Plating and locking elements are applied through partner facilities to the standard.
Lead time
Quoted on each order. Because the parts are machined from bar rather than scheduled through a heading run, lead time is set by machining capacity and material availability. Ask for the current lead time with your RFQ.
Quality
Cyclone’s published certifications include AS9100D, AS9120B, ISO 9001:2015, API Spec Q1, API 20E and API 20F. See quality and certifications.
Documentation
Material test reports and certificates of conformance ship with the order. Additional inspection reports and documentation are quoted to the purchase order.
Questions before you quote
Can the shoulder be ground to a tighter tolerance than the sheet?
Send the drawing. Cyclone machines to the standard or to your tighter requirement when the drawing calls for it.
Does Cyclone stock these?
No. Every part is made to order from certified bar, which is why there is no minimum quantity and why the quote confirms sizes and lead time.
Can you quote a cancelled or superseded number?
Yes. Many MS sheets were reissued as NASM or SAE AS standards with the part numbers unchanged. Send the number on your drawing and the quote names the current document.