The decoder
Runs in your browser. Try AN470AD4-6, MS20426DD5-8, CR3213-4-02, QQ-A-250/4, AN4C12A or MS21047L08. For nutplates, add a quantity to weigh the batch.
What it reads, and from where
Solid rivets. AC 43.13-1B Figure 4-4 breaks MS20470AD4-7 into head type (MS20470), material code (AD), diameter in 1/32 in (4) and length in 1/16 in (7). Its table gives the codes: A 1100, AD 2117, D 2017-T, DD 2024, B 5056, E 7050, M Monel. Paragraphs 4-57 and 7-1 give the links. MS20470 supersedes AN470, MS20426 supersedes AN426, and all protruding-head rivets (AN430 round, AN442 flat, AN455 and AN456 brazier) may be replaced by MS20470.
CherryMAX. In CR3213-4-02 the middle dash is the diameter in 1/32 in and the last the maximum grip in 1/16 in. CR3212 is the 100° head, and CR3243 and CR3242 are the oversize series.
Sheet specifications. MIL-HDBK-5J tabulates the material specifications for each alloy and product form. For bare 2024 sheet and plate it lists AMS 4037, AMS 4035 and AMS-QQ-A-250/4. The decoder shows the other specifications listed for the same alloy and form. They are not declared interchangeable: tempers and requirements differ by document.
AN bolts and MS nutplates. These come from the AN bolt and nutplate data sheets, each transcribed from its standard. In AN4C12A, AN4 is 4/16 in, C corrosion-resistant steel, -12 the grip and length from the standard's table, A an undrilled shank. In MS21047L08K, L is dry film lubricant, 08 the thread size and K countersunk or dimpled rivet holes. The decoder draws the part to scale from its row, weighs a batch where the standard gives a weight per 100, and links to that row.
Why size first. Some standards code sizes in fractions of an inch, others in millimetres. A cross made by copying digits gives a wrong part. Every number here is turned into its physical size before any other number is shown.
Worked example
A 1983 repair drawing calls for AN470AD4-6.
- AN470: universal head. AD: 2117. 4: 4/32 = 1/8 in (3.18 mm). 6: 6/16 = 3/8 in (9.53 mm) under the head.
- AC 43.13-1B 7-1a: MS20470 supersedes AN470.
Order MS20470AD4-6: the same rivet under the number that superseded it.
Limits — when NOT to use this
- The SRM and IPC govern. A cross shown here is what a source states, not an approval to substitute on a given aircraft.
- Few families so far. AN bolts beyond AN8, NAS nutplates, other blind fasteners, European LN and NF L numbers and Airbus ASNA numbers are not covered until we hold the documents that define them.
- Specifications are not part numbers. Two specifications for the same alloy and form can differ in temper, tolerances and testing.
Questions people actually ask
Is MS20470 the same as NASM20470?
The decoder reads NASM20470 with the same numbering as MS20470, but the relationship between the two standards is not in our primary sources, so it does not declare them the same.
Why no LN 9198 or ASNA cross?
Those are millimetre or Airbus-coded standards. We will add them when we hold the documents that define them, rather than crossing by rounding.
Sources
- FAA AC 43.13-1B CHG 1, Figure 4-4, par. 4-57 and 7-1 — rivet part number breakdown and material codes; MS20470 supersedes AN470, MS20426 supersedes AN426; protruding heads replaceable by MS20470; AN430, AN442, AN455/456 head types.
- MIL-HDBK-5J, Tables 3.2.1.0(a), 3.2.3.0(a), 3.6.2.0(a), 3.7.6.0(a) — material specifications and product forms for 2014, 2024, 6061 and 7075.
- AN3 thru AN20 Rev. 12, 14 Jan 1991 — Bolt, Machine, Aircraft — AN bolt codes, grip and length. Each MS nutplate standard is cited by revision on its own data sheet.
- Aircraft Spruce catalogue and CherryMAX distributor data sheets — CherryMAX dash numbering, grip ranges and the CR324x oversize series.