Reading an Eddie-Pin number
Where to buyEL120 5 N N 8-6 Y (the maker's example, p. 4): EL is the Eddie-Pin prefix; 1 the head configuration (100° reduced flush shear head); 20 the material and strength level (6Al-4V titanium, 95 ksi shear); 5 the pin series (generic, lubricated); N the finish (titanium, no finish); N the lubricant code; 8 the nominal diameter in 1/32 in (1/4 in); 6 the maximum grip in 1/16 in; Y the oversize indicator (1/32 in). A hex-recess pin ends there; a Spline-Lok recess is marked S at the end of the older number, or the family prefix is ELS in the newer one (pp. 5 and 6).
Head configurations include 1 (100° reduced flush shear), 2 (protruding shear), 3 (100° flush tension), 4 (protruding tension), 5 (flush MS20426 head), 9 (self-sealing head) and 90 to 93 for 130°, 120° and 100° flush shear and 130° crown shear (p. 7). Material and strength codes: 10 alloy steel 95 ksi; 20 6Al-4V titanium 95 ksi; 30 A-286 CRES 95 ksi; 35 Inconel 718 108 ksi; 38 Inconel 718 125 ksi; 40 PH13-8Mo 125 ksi (p. 7).
Finish codes include A (anodize), E (phosphate fluoride), H (aluminium coat), N (none on titanium, passivate on CRES and Inconel), P (cadmium), V and W (IVD aluminium coat) (p. 8).
Reading an Eddie-Nut number
EN 1 2 8 3 N D 8 Y (p. 9): EN is the Eddie-Nut prefix; 1 the system type (1 shear, 2 tension); 2 the configuration (1 standard base, 2 captive washer, 3 self-aligning, 4 self-sealing); 8 the material (0 is 7075-T73 or 7175-T73 aluminium, 3 A-286 CRES, 8 3Al-2.5V titanium); 3 the nut series; N the finish; D the lubricant; 8 the diameter in 1/32 in; Y the oversize indicator (pp. 9 to 11).
The nut has three external lobes that serve as driving lands; the free-running thread and the lobes make a foreign-object-debris-free installation (p. 2). Conventional hex nuts cannot be used on Eddie-Pins, and removed nuts are not reused (p. 24).
Recommended hole by fit, with the drill inside the range
| Dash (nominal) | Clearance fit | Close ream | Transition fit | Interference fit |
|---|---|---|---|---|
| -5 (5/32) | 0.164–0.167 · #19 (0.1660) | 0.1635–0.1645 · no standard drill inside: ream | 0.161–0.164 · #20 (0.1610) | 0.1595–0.1615 · #20 (0.1610) |
| -6 (3/16) | 0.190–0.193 · #11 (0.1910) | 0.1895–0.1905 · no standard drill inside: ream | 0.187–0.190 · #12 (0.1890) | 0.1855–0.1875 · 12/64 (0.1875) |
| -8 (1/4) | 0.250–0.253 · 16/64 (0.2500) | 0.2495–0.2505 · 16/64 (0.2500) | 0.247–0.250 · 16/64 (0.2500) | 0.2455–0.2475 · D (0.2460) |
| -10 (5/16) | 0.312–0.315 · 20/64 (0.3125) | 0.312–0.313 · 20/64 (0.3125) | 0.309–0.313 · 20/64 (0.3125) | 0.308–0.310 · no standard drill inside: ream |
| -12 (3/8) | 0.375–0.378 · V (0.3770) | 0.3745–0.3755 · 24/64 (0.3750) | 0.371–0.375 · 24/64 (0.3750) | 0.3705–0.3725 · no standard drill inside: ream |
| First oversize, 1/64 in | ||||
| -6 (13/64) | 0.203–0.206 · #6 (0.2040) | 0.2026–0.2036 · 13/64 (0.2031) | 0.200–0.203 · #7 (0.2010) | 0.1986–0.2006 · #8 (0.1990) |
| -8 (17/64) | 0.266–0.269 · H (0.2660) | 0.2651–0.2661 · 17/64 (0.2656) | 0.263–0.266 · 17/64 (0.2656) | 0.2611–0.2631 · no standard drill inside: ream |
| -10 (21/64) | 0.328–0.331 · 21/64 (0.3281) | 0.3276–0.3286 · 21/64 (0.3281) | 0.325–0.328 · no standard drill inside: ream | 0.3236–0.3256 · no standard drill inside: ream |
| -12 (25/64) | 0.391–0.394 · no standard drill inside: ream | 0.3901–0.3911 · 25/64 (0.3906) | 0.388–0.391 · 25/64 (0.3906) | 0.3861–0.3881 · no standard drill inside: ream |
| Second oversize, 1/32 in | ||||
| -6 (7/32) | 0.219–0.222 · #2 (0.2210) | 0.2182–0.2192 · 14/64 (0.2188) | 0.216–0.219 · 14/64 (0.2188) | 0.2142–0.2162 · no standard drill inside: ream |
| -8 (9/32) | 0.281–0.284 · 18/64 (0.2812) | 0.2807–0.2817 · 18/64 (0.2812) | 0.278–0.281 · K (0.2810) | 0.2767–0.2787 · J (0.2770) |
| -10 (11/32) | 0.344–0.347 · no standard drill inside: ream | 0.3432–0.3442 · 22/64 (0.3438) | 0.341–0.344 · 22/64 (0.3438) | 0.3392–0.3412 · no standard drill inside: ream |
| -12 (13/32) | 0.406–0.409 · 26/64 (0.4062) | 0.4057–0.4067 · 26/64 (0.4062) | 0.403–0.406 · Y (0.4040) | 0.4017–0.4037 · no standard drill inside: ream |
Hole limits in inches from the maker's table, p. 12; the drill is our pick of the number, letter or fraction drill whose size falls inside the range, closest to the middle, and “ream” where none does. Clearance fit is recommended whenever steel, titanium or composites are in the stack; close ream for net to minimal clearance; transition fit in aluminium where a close to slight interference fit is needed; interference fit in aluminium for improved load transfer and fatigue performance (p. 12 note). Fillet relief radius under the head: .025 to .035 in for -5, -6 and -8 protruding heads, up to .030 to .040 in for -10 and -12 (p. 14).
Recommended grip ranges
| Grip dash | Grip range, in |
|---|---|
| 3 | 0.126–0.188 |
| 4 | 0.189–0.250 |
| 5 | 0.251–0.312 |
| 6 | 0.313–0.375 |
| 7 | 0.376–0.438 |
| 8 | 0.439–0.500 |
| 9 | 0.501–0.562 |
| 10 | 0.563–0.625 |
| 11 | 0.626–0.688 |
| 12 | 0.689–0.750 |
Maker's table, p. 15. The grip gage (P/N EB2G1400) has a tapered probe hooked on the back of the material and is read to the nearest 1/16 in at the work surface; if the sheet line falls between values, round up to the next grip. A protruding-head scale and a notched scale for countersunk heads are on the gage (pp. 15 and 16).
Installing, inspecting and removing
| Step | What | Source |
|---|---|---|
| Hole | Drill and ream to the fit on the drawing; deburr every hole edge in the stack; hole angularity beyond 2° is to be avoided; the countersink angle is the fastener angle ±1° | Process manual pp. 13, 14 |
| Start | The pin is not pulled into the hole by the nut; wipe excess sealant off the thread; hand-start the nut at least 3/4 turn and spin it down to the structure | p. 17 |
| Drive | Tool with a centre Spline-Lok or hex key to stop the pin turning in clearance, close ream or transition holes; driver bottomed on the nut base, square to the fastener; it turns free when the lobes have been swaged into the flutes | p. 18 |
| If it fails | Replace pin and nut if the pin spins; an incompletely swaged nut is removed and replaced with its pin, never re-swaged | p. 18 |
| Seat | The head contacts the countersink so that a .002 in feeler gage cannot enter; it must wedge before touching the shank; shaving a flush head to meet flushness is not permitted | p. 19 |
| Protrusion | Check with the MAX / MIN gage after the nut is installed and with no gaps in the structure: too short means the next longer grip, too long the next shorter | p. 20 |
| Remove | Remove the nut with a hand or power removal tool; a key holds the pin in clearance holes; after sealant sets a power tool cannot be used; nuts are not reused and the pin is replaced | pp. 23, 24 |
The Eddie-Bolt 2 is installed with a hand or power driver that has an internal three-sided shape (pp. 25 and following). The FAA handbook describes it as usable in clearance or interference-fit holes (FAA-H-8083-31B p. 4-53) and as a natural choice for carbon-fibre composite structure (p. 7-46).
Questions people actually ask
Which hole for an Eddie-Bolt in aluminium?
The maker recommends transition fit where a close to slight interference fit is needed and interference fit for better load transfer and fatigue life (Eddie-Bolt Process Manual p. 12). In steel, titanium or composite stacks it recommends clearance fit.
What do X and Y at the end of the number mean?
X is a 1/64 in oversize pin and Y a 1/32 in oversize pin; each has its own hole table (p. 12).
Can I re-torque a nut that did not swage?
No. An incompletely swaged nut is removed and replaced with a new nut and pin (p. 18).
Limits of this guide
What the sources support, and no further.
- Strength values: only the shear levels of the material code are given here (95 to 125 ksi); no joint allowable.
- Other codes: the lubricant letters and the nut-series chart are in the maker's manual; only those read are given.
- Equivalents: no public cross to another make was found; the FAA handbook only says it looks like a Hi-Lok.
- Reference data, not approved data. The SRM, the drawing or the approved repair data governs over every figure here.
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Sources
- Eddie-Bolt Process Manual (Howmet Fastening Systems) — Pp. 4 to 11 part number system; p. 12 recommended hole diameters; pp. 13, 14 hole preparation; p. 15 grip ranges; pp. 17 to 20 installation and inspection; pp. 23, 24 removal.
- FAA-H-8083-31B, Aviation Maintenance Technician Handbook, Airframe — P. 4-53 Eddie-Bolt 2 pin; p. 7-46 Eddie-Bolt fasteners.