Composi-Lok II
Monogram · Blind bolt
The composite blind-bolt standard — biggest blind footprint, high clamp-up.
aka CompositLok · Composilok · composite blind bolt
P/N: MBF21xx · e.g. MBF2112-06-500
Schematic cross-section, not to scale. Orange = the large blind-side upset; high clamp-up.
Shear
75–75 ksi
Blind bulb
large
Max service
≤ 900°F
Lead-time risk
High
Diameters
5/32, 3/16, 1/4, 3/8"
Datasheet strength · 75 ksi shear (6-4 Ti screw); double-shear 4,600 lb min — Monogram catalogue.
Head styles
- Protruding
- 100° flush
Standards
- NAS (Composi-Lok series)
Materials & galvanic compatibility vs CFRP
| Alloy | Shear | vs CFRP | Notes |
|---|---|---|---|
| Titanium (Ti-6Al-4V) | 75 ksi | low | 6-4 Ti screw/nut, preferred for CFRP |
| A286 CRES | 75 ksi | med | stainless sleeve |
Install tooling & training
- Tool
- Monogram installation tool (hand or compact power)
- Special / proprietary
- Special tooling · proprietary
- Training
- Specialty training — clamp-up control is critical on composite.
- Inspection
- Pintail break + protrusion; verify upset.
Longer sleeve + corebolt form a very large blind-side upset at standard air pressure; installs and verifies entirely from one side.
Sourcing
Lead-time risk: High — Specialty fastener; lead times run long, especially titanium.
- Peerless Aerospace Fastener ↗
Largest dedicated aerospace fastener inventory; approved source for major OEMs + DoD; multi-year fixed pricing, bonded storage, designated hold-shelf, min/max + safety-stock programs.
- Incora ↗
Authorized distributor for 60+ manufacturers; AS9100 / EN9120 / FAA AC 00-56; strong vendor-managed-inventory (VMI) and kitting programs.
- FDH Aero ↗
Single-source partner across hardware, electrical, consumables and licensed products; vendor-managed inventory.
Need a price or lead time?
Build a spec-complete RFQ and send it to distributors who stock Composi-Lok II.
Strengths
- +Engineered for composites — very large blind-side footprint
- +High controlled clamp-up without delamination
- +Qualified on 75+ aircraft programs
Trade-offs
- −Specialty installation tool (cost + training)
- −Long lead times, especially titanium
- −Higher unit cost
Typical applications
- · High-strength composite airframe structure
- · Control surfaces, spars, splice joints
- · Composite-to-metal primary structure