AN173 through AN186 close-tolerance bolts
The close-tolerance version of the AN3 bolt, with a ground shank for light-drive fits, #10-32 through 1-12 UNF-3A.
AN173–AN186, machined to the standard.
AN173 through AN186 is the close-tolerance aircraft machine bolt: the same hex head and fine thread as AN3 through AN20, with the shank held to a close tolerance for joints that see load reversal and vibration. The head is marked with a triangle to identify it. The AN sheet was cancelled in 2021 and is now NASM173 thru NASM186; part numbers are unchanged.
- 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.
AN173–AN186 at a glance
| Detail | Specification |
|---|---|
| Standard | AN173 thru AN186, now NASM173 thru NASM186 (active) |
| Title | Bolt, Machine, Close Tolerance, Aircraft |
| Material | Alloy steel, cadmium plated (corrosion-resistant steel and aluminum codes inactive for design since 1952) |
| Thread | UNF-3A, #10-32 through 1-12 |
| Head | Hex head, triangle marked; drilled head and shank as coded |
| Strength | Same rated loads as AN3 thru AN20; 125,000 psi minimum tensile |
| Typical use | Structural joints subject to load reversal and vibration, light-drive fit |
Part numbers covered: AN173, AN174, AN175, AN176, AN177, AN178, AN179, AN180, AN182, AN184, AN186. Reference only; the current revision of the standard on your order governs.
Reading the part number.
| Element | Meaning |
|---|---|
| AN173 … AN186 | Diameter: AN173 = #10-32 through AN186 = 1-12 |
| Dash number | Grip or length, from the sheet table |
| A after the dash | Undrilled shank |
| H before the dash | Drilled head and shank; with A after the dash, drilled head only |
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
What makes a close-tolerance bolt different?
The shank diameter is held to a tighter tolerance than a standard AN bolt so the bolt fits the hole with little or no clearance. The standard calls for a triangle mark on the head.
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.