MS20073 and MS20074 drilled-head aircraft bolts
The aircraft bolt with a deeper hex head drilled for safety wire, replacing the AN73 through AN81 series. #10 through 3/4 in.
MS20073, MS20074, machined to the standard.
MS20073 is the fine-thread (UNF-3A) drilled-head aircraft bolt and MS20074 the coarse-thread (UNC-3A) version. Both have a hex head deeper than the AN3 bolt, drilled with three holes for safety wire, and an X marked on the head. The shank cotter pin hole is drilled when the part number calls for it. Both sheets were cancelled in 2000 and are now NASM20073 and NASM20074.
- 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.
MS20073, MS20074 at a glance
| Detail | Specification |
|---|---|
| Standard | MS20073 and MS20074, now NASM20073 and NASM20074 (active) |
| Title | Bolt, Machine, Aircraft, Drilled Head, Fine Thread / Coarse Thread |
| Material | Steel per MIL-B-6812, cadmium plated |
| Thread | MS20073: UNF-3A, #10-32 through 3/4-16. MS20074: UNC-3A, #10-24 through 3/4-10 |
| Head | Hex head, drilled three holes for lockwire, X marked |
| Strength | Same rated loads as AN3 thru AN20 |
| Typical use | Airframe and engine locations where the bolt head must be safety-wired |
Part numbers covered: MS20073 (fine thread), MS20074 (coarse thread). Reference only; the current revision of the standard on your order governs.
Reading the part number.
| Element | Meaning |
|---|---|
| First dash | Diameter code: 03 = #10, 04 = 1/4, 05 = 5/16, 06 = 3/8, 07 = 7/16, 08 = 1/2, 09 = 9/16, 10 = 5/8, 12 = 3/4 |
| Second dash | Grip or length, from the sheet table |
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
Do these replace AN73 through AN81?
Yes. The MS20073 and MS20074 sheets superseded the AN73 through AN81 drilled-head bolts.
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.