NAS6304 bolts
NAS6304 is the 1/4-28 UNJF-3A size of the NAS6303–NAS6320 close-tolerance hex head bolt: A286, short thread, 160 ksi. Machined to order in Houston.
NAS6304, machined to the standard.
NAS6304 is one diameter in the NAS6303–NAS6320 series. The last two digits give the diameter in sixteenths of an inch, so NAS6304 is the 1/4 in. bolt, threaded 1/4-28 UNJF-3A. The dash number that follows gives the grip length in sixteenths: NAS6304-10 has a 5/8 in. grip.
NAS6303 through NAS6320 is the corrosion and heat resistant counterpart of NAS6203: the same close-tolerance hex head bolt with a short thread and reduced major diameter, made from A286 (AMS 5731, 5732, 5737 or 5853) and heat treated to 160 ksi minimum tensile. Cadmium plated by default, with an unplated passivated option.
- 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.
NAS6304 at a glance
| Detail | Specification |
|---|---|
| Part number | NAS6304 |
| Thread | 1/4-28 UNJF-3A |
| Nominal diameter | 0.250 in. |
| Standard | NAS6303 thru NAS6320 (current) |
| Material | A286 per AMS 5731, 5732, 5737 or 5853; cadmium plated (default) or passivated unplated (U) |
| Strength | 160,000 psi minimum tensile |
| Head | Low-profile hex head; drilled shank (D), drilled head (H) |
| Dash number | Grip length in sixteenths of an inch |
Reference only; the current revision of the standard on your order governs.
Reading a NAS6304 part number.
A complete callout is the base number, a dash number for grip, and code letters for options: NAS6304-10 is the plain bolt with a 5/8 in. grip. The table shows the code letters this series uses.
| Element | Meaning |
|---|---|
| NAS6304 | 1/4 in. diameter, 1/4-28 UNJF-3A thread |
| Dash number | Grip in 1/16 in. increments |
| U | Unplated, passivated |
| L | Self-locking element |
| D / H | Drilled shank / drilled head |
NAS6304 dash numbers and grip lengths
The dash number is the grip, the unthreaded length under the head, in sixteenths of an inch. The standard lists the dash numbers available for each diameter; longer grips continue the same rule.
| Dash | Grip | Dash | Grip |
|---|---|---|---|
| -1 | 1/16 (0.0625) in. | -25 | 1-9/16 (1.5625) in. |
| -2 | 1/8 (0.125) in. | -26 | 1-5/8 (1.625) in. |
| -3 | 3/16 (0.1875) in. | -27 | 1-11/16 (1.6875) in. |
| -4 | 1/4 (0.25) in. | -28 | 1-3/4 (1.75) in. |
| -5 | 5/16 (0.3125) in. | -29 | 1-13/16 (1.8125) in. |
| -6 | 3/8 (0.375) in. | -30 | 1-7/8 (1.875) in. |
| -7 | 7/16 (0.4375) in. | -31 | 1-15/16 (1.9375) in. |
| -8 | 1/2 (0.5) in. | -32 | 2 in. |
| -9 | 9/16 (0.5625) in. | -33 | 2-1/16 (2.0625) in. |
| -10 | 5/8 (0.625) in. | -34 | 2-1/8 (2.125) in. |
| -11 | 11/16 (0.6875) in. | -35 | 2-3/16 (2.1875) in. |
| -12 | 3/4 (0.75) in. | -36 | 2-1/4 (2.25) in. |
| -13 | 13/16 (0.8125) in. | -37 | 2-5/16 (2.3125) in. |
| -14 | 7/8 (0.875) in. | -38 | 2-3/8 (2.375) in. |
| -15 | 15/16 (0.9375) in. | -39 | 2-7/16 (2.4375) in. |
| -16 | 1 in. | -40 | 2-1/2 (2.5) in. |
| -17 | 1-1/16 (1.0625) in. | -41 | 2-9/16 (2.5625) in. |
| -18 | 1-1/8 (1.125) in. | -42 | 2-5/8 (2.625) in. |
| -19 | 1-3/16 (1.1875) in. | -43 | 2-11/16 (2.6875) in. |
| -20 | 1-1/4 (1.25) in. | -44 | 2-3/4 (2.75) in. |
| -21 | 1-5/16 (1.3125) in. | -45 | 2-13/16 (2.8125) in. |
| -22 | 1-3/8 (1.375) in. | -46 | 2-7/8 (2.875) in. |
| -23 | 1-7/16 (1.4375) in. | -47 | 2-15/16 (2.9375) in. |
| -24 | 1-1/2 (1.5) in. | -48 | 3 in. |
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 thread is NAS6304?
1/4-28 UNJF-3A. The bolt has a 0.250 in. nominal diameter.
What does the dash number on NAS6304 mean?
The grip length in sixteenths of an inch. NAS6304-8 has a 1/2 in. grip and NAS6304-16 has a 1 in. grip.
What material is NAS6304?
A286 per AMS 5731, 5732, 5737 or 5853; cadmium plated (default) or passivated unplated (U). Minimum tensile strength is 160,000 psi.
Does Cyclone stock NAS6304?
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.
Is DFARS-compliant material available?
Yes, on request. This refers to material sourcing; state the DFARS clause on your purchase order.