8 Bolt Couplings

Eight bolt couplings are used on eight bolt hole gearbox output flanges. Spigots or pilots can be either male or female. Isoflex couplings are configured to the most common flanges. On Isoflex 8 bolt couplings, special steel spigots, pilots or registers are fitted to maintain absolute dimensions.

Note: certain couplings need a T-bush kit. Isoflex can supply certain adapters.

* Spicer bolt pattern


ModelGearbox Flange
Bolt Circle
Diameter (mm)(in)
Gearbox Flange
Bolt Size
Gearbox Flange
Index Ring
Gearbox Flange
Index Ring
Diameter (mm)(in)
Isoflex Coupling
Diameter (mm)(in)
Isoflex Coupling
Diameter (mm)(in)
Isoflex Coupling
Thickness (mm)(in)
Heavy Duty (Nm)(ftlb)Medium Duty (Nm)(ftlb)Pleasure Craft (Nm)(ftlb)Data Sheet
IFC-8100-HT190.5 [7 1/2"]7 1/2M16 SHCSM16 SHCS [5/8" approx.]MM152.4 [6"]627510.83953.74381 1/285006260127509390Use MediumUse MediumDownload
IFC-8100-95190.5 [7 1/2"]7 1/2M16 SHCSM16 SHCS [5/8 approx.]MM152.4 [6"]627510.83953.74381 1/268505040102757570Use MediumUse MediumDownload
IFC-81610-HT*155.6 [6 1/8"]6 1/83/8" UNF3/8" UNFFF168.28 [6 5/8"]6 5/82208.66501.97281.103700272055004050Use MediumUse MediumDownload
IFC-81710-HT*184.15 [7 1/4"]7 1/43/8" UNF3/8" UNFFF196.85 [7 3/4"]7 3/42419.50742.93281.1Download
IFC-8200-HT190.5 [7 1/2"]7 1/2M16 SHCSM16 SHCS [5/8" approx.]MM152.4 [6"]62429.53953.74381 1/279005820118508730Use MediumUse MediumDownload
IFC-8200-95190.5 [7 1/2"]7 1/2M16 SHCSM16 SHCS [5/8" approx.]MM152.4 [6"]62429.53953.74381 1/24500331067504970Use MediumUse MediumDownload
IFC-8300-95152.4 [6"]6M16 SHCSM16 SHCS [5/8" approx.]MM95.25 [3 3/4"]3 3/41957.68732.87381 1/2300022104500331051003750Download
IFC-8400-HT2007 7/8M16 SHCSM16 SHCS [5/8" approx.]MM1104.3327510.83752.95381 1/285006260127509560Use MediumUse MediumDownload
IFC-8400-952007 7/8M16 SHCSM16 SHCS [5/8" approx.]MM1104.3327510.83752.95381 1/270005150105007730Use MediumUse MediumDownload
IFC-8534-95222.25 [ 8 3/4"]8 3/43/4" UNC3/4" UNCMM127 [5"]531512.40752.9545.01 3/485006260127509390Use MediumUse MediumDownload
IFC-8600-952309.06M20M20 [3/4" approx.]MM1505.9131512.401003.9445.01 3/486506370129759560Use MediumUse MediumDownload
IFC-8690-95228.6 [9"]93/4" UNC3/4" UNCMM152.4 [6"]630011.81953.7445.01 3/486506370129759560Use MediumUse MediumDownload
IFC-8695-HT241.3 [9 1/2"]9 1/23/4" UNC3/4" UNCMM152.4 [6"]633012.99953.7445.01 3/41335098302010014810Use MediumUse MediumDownload
IFC-8695-95241.3 [9 1/2"]9 1/23/4" UNC3/4" UNCMM152.4 [6"]633012.99953.7445.01 3/490006630135009940Use MediumUse MediumDownload
IFC-8700-95280117/8" UNC7/8" UNCFF200 [7 7/8"]7 7/835513.98752.9550.021000073701500011050Use MediumUse MediumDownload
IFC-8800-9534013.391" UNC1" UNCMM1807.0945517.911305.1260.02.3622500165803375024870Use MediumUse MediumDownload
IFC-8900-9530011.807/8" UNC7/8" UNCMM1807.0940015.751305.1250218300134802750020260Use MediumUse MediumDownload