Measure what you can. Leave the rest blank.
Thread diameter is measured across the threads with a caliper. Length is measured to within ±1.5 mm, so a reading of 16 will also find 15 and 17.
e.g. NAS1102-4-20 or NAS1351N3-8
Which standards this page can answer for
The last nine rows, and the numbers 11.14 added to MS24693, MS24694, MS35206/207 and MS51957/958, come from the Skybolt 2017 AN-MS-NAS catalogue tables, not from this aircraft’s parts catalogue. The card says which.
| Standard | Screws | What it is | Head |
|---|---|---|---|
| NAS1102 | 137 | 100° flat head, cruciform recess, full thread | |
| NAS1801 | 101 | Hex head with cruciform recess — takes a socket | |
| NAS1100 | 96 | Pan head, cruciform recess | |
| MS51957/958 | 34 | Pan head, cross recessed, CRES | |
| MS35206/207 | 101 | Pan head machine screw | |
| MS24694 | 89 | 100° flat countersunk, structural | |
| MS24693 | 137 | 100° flat countersunk, cross recessed | |
| NAS514 | 87 | 100° flat head machine screw | |
| NAS1351 | 60 | Socket head cap screw — hex key | |
| NAS1101 | 43 | Pan head, cruciform recess | |
| NAS1096 | 42 | Hex head recessed screw | |
| NAS1352 | 30 | Socket head cap screw, coarse thread | |
| NAS517 | 26 | 100° flat head, close tolerance | |
| NAS1802 | 26 | Hex head, coarse thread | |
| NAS600–604 | 63 | Pan and flat head machine screws | |
| NAS623 | 17 | Pan head, cruciform recess | |
| MS35265/266 | 117 | Fillister head, slotted, drilled for lockwire (AN500/AN501 equivalents) | |
| AN526 | 108 | Truss head, cruciform recess | |
| AN500/501 | 100 | Fillister head, slotted, drilled | |
| AN515/520 | 94 | Pan head, cruciform recess (MS35206/207 equivalents) | |
| AN507 | 85 | 100° flat head, cruciform recess (MS24693 equivalent) | |
| MS27039 | 81 | Pan head, structural, cruciform recess | |
| AN509 | 80 | 100° flat head, structural (MS24694 equivalent) | |
| AN525 | 52 | Washer head, cruciform recess — superseded by MS27039 | |
| MS35214/215 | 19 | Pan head, brass, black oxide — instrument screws |
REFERENCE ONLY — not authorized for maintenance, repair or return-to-service. Torque values reproduced from FAA AC 43.13-1B Table 7-1 (public domain). A torque published in a maintenance task is the one to use. Figures are clamping torque for the nut, dry and oil-free: with a self-locking nut the prevailing torque is measured and added, and a lubricated joint takes 80% of the dry value. Screws reached through a FIN are the ones in that FIN’s parts catalogue figure, the whole assembly drawing, not necessarily the ones holding the item. Thread sizes are decoded from the part number, not published per part number by this site. Head diameter and height are catalogue figures for the standard, not a measurement of the screw in your hand \u2014 use them to know whether a head will sit flush or foul, and measure when it matters.