Name: Visu-Lok
Brand: Monogram

Blind (one-sided), threaded blind bolt: “Torque is applied to the screw while the DRIVE NUT is held stationary.” (Monogram Visu-Lok II brochure, p.3, How They Work)

Shear: 50-112 ksi
Blind bulb: standard
Install: One-side install
Diameters: 5/32, 3/16, 1/4, 5/16, 3/8"
Lead-time risk (SpecLok assessment): High

Typical applications

·Metallic structures (Monogram catalog)

Strengths

+"Self inspecting" from one side: break-off height and seating torque (brochure p.2)
+"Guaranteed 20% minimum pre-load" (brochure p.2)
+Alloy steel, CRES (A-286), H-11, titanium and aluminum series (brochure p.8-12)

Trade-offs

−Monogram positions it for metallic structures (catalog)

Also called VisuLok, Visu-Lok II, PLT series. P/N: PLT5 series · e.g. PLT5170-06-05 (100° flush head, titanium) / PLT5270 (hex head, titanium)

Datasheet strength: Rated 75 KSI (titanium, Monogram catalog chart); "as high as 112 K.S.I. available" (Visu-Lok II brochure p.2); double shear by material on brochure p.4.

Standards

NAS1675 (procurement: aluminum, alloy steel, A-286)
PLT 5000 (other materials)

Materials and galvanic compatibility vs CFRP

Alloy	Shear	vs CFRP	Notes	Source
A286 CRES	75 ksi	low	A-286 nut, screw & sleeve (PLT5x2x)	Derived: brochure p.4 double shear (Ti & A-286 4,600 lb at -6) ÷ shank area; catalog chart rates Ti 75 KSI
Titanium	75 ksi	low	6-4 Ti nut & screw, CRES sleeve (PLT5x7x)	Monogram catalog chart: 75 KSI; brochure p.4
Alloy steel	85 ksi	high	4130/4140/8740 nut & screw (PLT5x1x)	Derived: brochure p.4 double shear 5,240 lb at -6 ÷ shank area
Alloy steel	112 ksi	high	H-11 (5% Cr) nut & screw (PLT5x5x)	Derived: brochure p.4 double shear 6,900 lb at -6; brochure p.2: "as high as 112 K.S.I."
Aluminum	50 ksi	high	7075 nut, alloy-steel screw (PLT513x), -5 to -8 only	Derived: brochure p.4 double shear 3,100 lb at -6 ÷ shank area

vs CFRP: MIL-STD-889C Table I, graphite column: high = incompatible in all environments; low = compatible except sea-water immersion; unrated = SpecLok has not read a rating for this material.About derived ksi

Derived ksi values are min shear ÷ nominal shank area, computed from the datasheet's lbf/kN figures; the datasheet itself publishes no ksi.

Specs source: Monogram Visu-Lok II brochure ↗: p.2-3 description & drive-nut install; p.4 strength tables; p.6 NAS cross-reference; p.7-12 head/material/grip tables. Metal-structure positioning & footprint: Monogram catalog. Lead-time risk is SpecLok's sourcing assessment, not a datasheet value.

3 head styles

Not redrawn: no head dimensions for this variant in the documents on file. The data at right is from the cited document.

100° flush head · 100°

PLT5110: Alloy steel (gold drive nut). Table 4: nut & screw alloy steel, sleeve 303 or 304 CRES
PLT5120: CRES (black drive nut). Table 4: nut, screw & sleeve corrosion & heat resistant steel, A-286
PLT5150: H-11 (red drive nut). Table 4: nut & screw 5% chrome steel H-11, sleeve A-286
PLT5170: Titanium (light gray drive nut). Table 4: nut & screw 6Al-4V titanium, sleeve 303 or 304 CRES-6 to -12. Grip dash = nominal grip in 1/16"; shortest grip -2 (-6), -3 (-8), -4 (-10, -12) (Table 1, Table 3).
PLT5130: Aluminum series: 7075 aluminum nut, alloy steel screw, CRES sleeve (Table 3)Monogram Visu-Lok II brochure, p.11 "Visu-Lok II 100° flush head, aluminum series" ↗

Sizes and grip: 4th digit = "D" dia shank configuration: 0 standard dia, 1 1/64th oversize, 4 ground shank (Table 1)

Head-specific tooling

MGF-( ) Flush head round gage (break-off check), PLT 5110, 5150, 5170 (Monogram PLT5002 Rev N, Table 11 ↗)

Source: Monogram Visu-Lok II brochure, p.7 "Visu-Lok II, 100° flush head series"; p.8 part number code (1 = flush head) ↗

From the Visu-Lok II brochure (2003). Later PLT drawings may add series not in it.

Head styles (manufacturer terms)

100° flush head (PLT5110, PLT5120, PLT5150, PLT5170, PLT5130)
Hex head (PLT5210, PLT5220, PLT5250, PLT5270, PLT5230)
100° reduced flush head (PLT5410, PLT5420, PLT5470)

Expanded view of the fastener (screw, sleeve and nut), with parts broken away and in axial section to show the construction.US 3,643,544, High-strength structural blind fastener for use in airplanes, rockets and the like (Massa), Fig. 2 ↗ · US patent drawingWhy this family: US 4,836,062: "The Visu-Lok type of blind fastener is disclosed in U.S. Pat. No. 3,643,544." Huck's US 5,603,592: fasteners of the type shown in 3,643,544 "have been sold under the trade names Visu-Lok and/or Jo-Bolt". Joseph H. Massa, National Screw and Manufacturing Co., 1972.

Axial sectional view, with portions in elevation, showing the fastener in position in two members to be secured together. — Expanded view of the fastener (screw, sleeve and nut), with parts broken away and in axial section to show the construction.US 3,643,544, High-strength structural blind fastener for use in airplanes, rockets and the like (Massa), Fig. 2 ↗ · US patent drawingWhy this family: US 4,836,062: "The Visu-Lok type of blind fastener is disclosed in U.S. Pat. No. 3,643,544." Huck's US 5,603,592: fasteners of the type shown in 3,643,544 "have been sold under the trade names Visu-Lok and/or Jo-Bolt". Joseph H. Massa, National Screw and Manufacturing Co., 1972.

Compare every family's mechanism

Installation verification and preload

Installed preload

Guaranteed minimum preload: 20% of minimum ultimate tensile strength (Visu-Lok II brochure); 3/16" Ti (PLT5170-06): 280 lb min · 1,200 lb typical (Monogram catalog chart)

This is the number behind the "Visu" self-inspection claim: break-off height gauging indicates correct grip, and a specified seating torque (4 in-lb at -5 to 30 in-lb at -12, PLT5002 Table 12) indicates clamp-up. Flush heads carry small recesses specifically so seating torque can be checked after install.

What to check after install

Stem break-off position vs head/skin per PLT5002 Table 11, e.g. PLT5170 flush: -5 +.020"/-.068", -6 +.015"/-.073", -8 +.010"/-.078"; protruding PLT5270: -6 +.098"/+.010".
Break too high = fastener too long; too low = too short. Remove, re-check grip, replace.
Seating-torque check (counter-clockwise, do not exceed) confirms clamp.

Check gauges (2) and sources.Details

Flush head round gages (MGF, MGFA, MGFB, MGR) and protruding head leaf gages (MGP), by part number and size (PLT 5002 Table 11). Gage rocks = break-off too high; does not rock on the low end = too low (PLT 5002).
Torque adaptors MHTFDN-( ) and MHTPDN-( ), -5 through -12, for the seating torque check (PLT 5002 Table 12).

Sources: PLT5002 installation spec · Visu-Lok II brochure · Monogram catalog (preload chart). Acceptance limits belong to the controlling spec; verify against your program's process documentation.

Print a shop verification card for the floor

Tool: Monogram installation tool engaging wrench flats and DRIVE NUT (Visu-Lok II brochure p.3); "use of existing NAS1675 tooling" (Monogram catalog)
Special / proprietary: Special tooling · proprietary
Training: Not stated in the cited documents.
Inspection: "Gauging the corebolt break-off height relative to the skin surface is an indicator of correct grip. The application of a specified torque load ... is an indicator of clamp-up" (brochure p.2).

"Torque is applied to the screw while the DRIVE NUT is held stationary ... causing the sleeve to be drawn up over the tapered nose of the nut ... When the sleeve forms tight against the blind side of the structure the screw will fracture in the break groove" (brochure p.3). Guaranteed 20% minimum pre-load (p.2).

The published install tool and nose for each size, other access options, and the gauges that check the install, from the manufacturer's own tool tables.

Dia.	Published tool + nose	Other access	Gauges
-5	MP550DN-5AA (MP550 + MPP-08 + MP-05)	Right angle, Close quarter	VLS-1A, MGF-05, MGP-05, MHTFDN-( ) / MHTPDN-( )
-6	MP550DN-6AA (MP550 + MPP-08 + MP-06)	Right angle, Close quarter	VLS-1A, MGF-06, MGP-06, MHTFDN-( ) / MHTPDN-( )
-8	MP550DN-8AA (MP550 + MPP-08 + MP-08)	Right angle, Close quarter	VLS-1A, MGF-08, MGP-08, MHTFDN-( ) / MHTPDN-( )
-10	MP550DN-11AA (MP550 + MPPDN + MP-10)	Close quarter	VLS-1A, MGF-10, MGP-10, MHTFDN-( ) / MHTPDN-( )
-12	MP550DN-12AA (MP550 + MPP-12 + MP-12)	Close quarter	VLS-1A, MGF-12, MGP-12, MHTFDN-( ) / MHTPDN-( )

Full tool tables, envelopes, clearances and source notes Compare tooling burden across all 25 families

Monogram PLT5002 Rev N (Visu-Lok II), §8.0 and Figure 9 (RK5000 kit)

“Visu-Lok II may be removed with the tooling shown in Figure 9 of this specification. Complete kits are available from Monogram Aerospace Fasteners. Contact factory for details.” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.17, §8.0 ↗
“Corebolt protrusion should be milled flush prior to removal.” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.12, Figure 9, Table 9, RK5000 Fastener Removal Kit ↗
“A complete tool consists of the air motor module, a nose piece module and a carbide.” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.12, Figure 9, Table 9, RK5000 Fastener Removal Kit ↗
“One blank receptacle #RC3076 should also be ordered for use with the depth to facilitate set up.” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.12, Figure 9, Table 9, RK5000 Fastener Removal Kit ↗

Cautions

“If a fastener has been removed, the same diameter Visu-Lok II can be reinstalled provided the hole has not been damaged. In the event that the hole has been damaged, the next larger diameter Visu-Lok II should be used. (Note: for flush head fasteners the countersink will have to be deepened).” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.13, §4.6 ↗
“This kit is used to remove alloy steel, titanium, aluminum, H-11 Visu-Loks and similar material. Contact factory for details.” Monogram PLT5002 Rev N (Visu-Lok II install spec), p.12, Figure 9, Table 9, RK5000 Fastener Removal Kit ↗

Removal tooling and drill sizes

Nominal diameter	Nose piece, flush	Nose piece, protruding hex	Carbide star drill	Drill size dia. +.0000/.0005	Depth gage
-5 (.1635)	RM3081-05	RM3082-05	RM3050-05	.1540	RC3031-5
-6 (.1980)	RM3081-06	RM3082-06	RM3050-06	.1890	RC3031-6
-8 (.2580)	RM3081-08	RM3082-08	RM3050-08	.2500	RC3031-8
-10 (.3105)	RM3153-10	RM3152-10	RM3050-10	.3020	RC3156-10
-12 (.3735)	RM3153-12	RM3152-12	RM3050-12	.3590	RC3156-12

Monogram PLT5002 Rev N (Visu-Lok II install spec), p.12, Figure 9, Table 9, RK5000 Fastener Removal Kit ↗

None of the removal procedures on file gives a composite-specific removal caution. The Monogram specs address composite at the hole instead: holes "reasonably round and free from burrs (metallic structure) and delamination (graphite/epoxy type structure)" (MBF2003 §5.1).

PLT5170
Diameters 3/16", 1/4", 5/16", 3/8" · 11 grip lengths
Every dash number Plan grips for your stack

Manufacturer: Monogram
Category: Hex-drive blind bolt

Datasheet (PDF) ↗
Manufacturer page ↗
Monogram Visu-Lok II brochure ↗: p.2-3 description & drive-nut install; p.4 strength tables; p.6 NAS cross-reference; p.7-12 head/material/grip tables. Metal-structure positioning & footprint: Monogram catalog.

Find the part number for your stack

DiameterStack thickness, in

Enter your stack thickness and diameter to get the PLT5170 dash number.

Dash numbers and grips: Monogram Visu-Lok II brochure p.7-8 (Tables 1 & 3) ↗

QtyInclude install tooling

Sourcing

Lead-time risk (SpecLok sourcing assessment): High

Get quotes: SpecLok sources this from authorized distributors and returns price, lead time and certs.You buy from the authorized distributor, who is named on your returned quote. SpecLok is free for buyers.

Supply signalfor this family

1,936 NSNs carry a part number of this family, recorded by 46 CAGE codes (FLIS, March 2025).
Last DoD award for RIVET,BLIND items (FSC 5320): 2026-06-26; 3,082 awards since 2025-10-01.
No SpecLok quotes yet.

A signal from records SpecLok holds, not availability, stock or a lead-time promise. FLIS lists who has recorded a part number for the item, not who makes it today. DoD awards carry no NSN or part number, so award activity is for the item name's class.

Sources: DLA FLIS Data Electronic Reading Room (PUB LOG) ↗, DLA PUB LOG ↗, USAspending.gov award search API ↗; DoD award data 2025-10-01 to 2026-07-06; compiled 2026-09-28.