What it is
Where to buyFAA-H-8083-31B (pp. 4-54 and 4-55) groups Jo-Bolts, Visu-Lok, Composi-Lok, OSI Bolt and Radial-Lok as drive-nut blind bolts for high-strength joints. In installation the screw advances through the nut body, drawing the sleeve over the tapered nose of the nut; when the sleeve forms tightly against the blind side, the screw fractures in its break groove. The stem of the Jo-Bolt, Visu-Lok and Composi-Lok II does not break off flush: a screw break-off shaver tool must be used if a flush installation is required. The stem of the newer Composi-Lok 3 and the OSI Bolt breaks off flush.
The Composi-Lok II and 3 are for composite structure; the ASNA types ASNA0012 and ASNA0013 are titanium blind bolts of the Composi-Lok type for composite structure, and ASNA302 and ASNA303 are of the Radial-Lok type.
Reading ASNA0012S08150
ASNA0012S08150: ASNA0012 is the 100° countersunk head (ASNA0013 is protruding); S the material code (printed with no meaning in the standard); 08 the diameter code (1/4 in nominal); 150 the grip code: the maximum grip in thousandths of an inch, here .100 to .150 in. For the Radial-Lok type ASNA302 the code N covers N minus 75 to N plus 25 thousandths: ASNA302S08100 is .050 to .125 in.
Hole and drill by diameter code, ASNA0012
| Code | Nominal | Fastener | Hole | Drill |
|---|---|---|---|---|
| -05 | 5/32 in | 0.1645 in (4.178 mm†) | 0.165–0.168 in (4.191–4.267 mm†) | #19 (0.1660 in; 4.22 mm) |
| -06 | 3/16 in | 0.1985 in (5.041 mm†) | 0.199–0.202 in (5.054–5.130 mm†) | #7 (0.2010 in; 5.11 mm) |
| -08 | 1/4 in | 0.2595 in (6.591 mm†) | 0.260–0.263 in (6.604–6.680 mm†) | G (0.2610 in; 6.63 mm) |
ASNA0012 data sheet; the ASNA0013, ASNA302 and ASNA303 sheets give the same codes. Units were printed with no unit, so the inch values are our conversion; the drill is the one of the site drill chart that falls inside the hole range.
Questions people actually ask
Which Composi-Lok breaks flush?
The Composi-Lok 3; the Composi-Lok II does not and needs the break-off shaver tool for flush surfaces (FAA-H-8083-31B p. 4-55).
How is the grip code read?
On the ASNA0012 it is the maximum grip in thousandths of an inch; on ASNA302 code N covers N−75 to N+25 thousandths.
Limits of this guide
What the sources support, and no further.
- Composi-Lok maker numbers (and oversize types) are not given: only the ASNA type standards.
- No strength data for composite joints is given.
- Material code S has no stated meaning in the standard.
- Reference data, not approved data. The SRM, the drawing or the approved repair data governs over every figure here.
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Sources
- FAA-H-8083-31B, Aviation Maintenance Technician Handbook, Airframe, chapter 4 — Pp. 4-54, 4-55: drive-nut blind bolts, flush break.
- ASNA0012, ASNA0013, ASNA302 and ASNA303 standard sheets — Diameter and grip codes, fastener diameter, hole.