Product Description
Martin Quadra-Flex® Type “B” Bushed Flange
Martin Sprocket & Gear — 10 Sizes, Taper-Lock Bushed
The Quadra-Flex® Type “B” Bushed flange is designed for larger shaft sizes and higher torque applications where a standard clamp-hub (Type S or J) won’t reach. It uses an interchangeable taper-lock bushing to grip the shaft, giving you a wider bore range per coupling size and the ability to swap shaft sizes by changing only the bushing — not the entire flange.
Each Type B flange mates with the same Quadra-Flex sleeve elements (JEM, Neoprene, Hytrel, etc.) used across the entire Quadra-Flex family. Two flanges plus one sleeve make a complete coupling assembly. The bushing and bushing bolts are ordered separately to match your exact shaft diameter and keyway.
Available in 10 sizes (6B through 16B) covering torque ratings from 585 to 47,250 in-lb. Select your coupling size above — the suffix indicates the required bushing type (JA, SH, SD, SK, SF, E, F, or J).
- Interchangeable Bushing — change shaft sizes by swapping the taper-lock bushing, not the flange
- Larger Bore Range — accommodates bigger shafts than Type S or J flanges of the same coupling size
- Taper-Lock Grip — positive concentric clamping eliminates set screw damage and shaft fretting
- Split Taper Design — easy installation and removal without pulling the coupling off the shaft
- Fail-Safe Interlock — coupling halves mesh so the drive continues even if the elastomer sleeve fails
- Bushing Bolts Available — each size has a matching bolt set variant for convenience
| Size | Bushing | Rated Torque | Max RPM | Sleeve Size | Max Bore | Flange Wt. |
|---|---|---|---|---|---|---|
| Type “B” Bushed Flanges — Torque & Bushing Reference | ||||||
| 6B | JA | 585 in-lb | 5,850 | 6 | 1" | 1.4 lb |
| 7B | JA | 940 in-lb | 4,950 | 7 | 1" | 1.9 lb |
| 8B | SH | 1,475 in-lb | 4,350 | 8 | 1-5/8" | 3.2 lb |
| 9B | SD | 2,340 in-lb | 3,600 | 9 | 2-1/8" | 5.0 lb |
| 10B | SK | 3,735 in-lb | 3,000 | 10 | 2-7/16" | 7.0 lb |
| 11B | SF | 5,890 in-lb | 2,500 | 11 | 3" | 12.0 lb |
| 12B | E | 9,360 in-lb | 2,100 | 12 | 3-3/8" | 18.0 lb |
| 13B | F | 14,750 in-lb | 1,800 | 13 | 4" | 30.6 lb |
| 14B | F | 23,400 in-lb | 1,500 | 14 | 4-15/16" | 48.8 lb |
| 16B | J | 47,250 in-lb | 1,200 | 16 | 6-1/2" | 120.0 lb |
Understanding the Bushing Types
Each Type B flange is designed for a specific taper-lock bushing series. The bushing slides into the flange bore, and tightening the bushing bolts draws the tapered surfaces together to lock concentrically onto the shaft. Order the bushing separately to match your shaft diameter.
| Bushing | Used On | Bore Range | OD | Length | Bolts |
|---|---|---|---|---|---|
| JA | 6B, 7B | 3/8" – 1" | 1.562" | 1.50" | 2 × 1/4"-20 |
| SH | 8B | 1/2" – 1-5/8" | 2.000" | 1.75" | 2 × 5/16"-18 |
| SD | 9B | 1/2" – 2-1/8" | 2.500" | 2.25" | 2 × 3/8"-16 |
| SK | 10B | 1/2" – 2-7/16" | 2.875" | 2.75" | 2 × 3/8"-16 |
| SF | 11B | 5/8" – 3" | 3.438" | 3.25" | 2 × 1/2"-13 |
| E | 12B | 5/8" – 3-3/8" | 3.875" | 3.50" | 2 × 1/2"-13 |
| F | 13B, 14B | 3/4" – 4-15/16" | 4.875" | 4.38" | 2 × 5/8"-11 |
| J | 16B | 1" – 6-1/2" | 6.625" | 5.25" | 2 × 3/4"-10 |
Ordering:
- Select your coupling size (e.g. “10B-SK”) to get the flange
- Add the “-BOLTS” variant for the matching bushing bolt set
- Order the taper-lock bushing separately to match your shaft bore and keyway
- Order the Quadra-Flex sleeve element separately (see Coupling Sleeve product)
- Two flanges + one sleeve + two bushings = one complete coupling
Where Type B Bushed Flanges Excel
- Large-Shaft Pump Drives — motor-to-pump on 2"+ shafts where Type S flanges can’t reach the bore size. Taper-lock eliminates set screw shaft damage on expensive pump shafts.
- Conveyor Head Shafts — gearbox-to-head-shaft connections on heavy belt conveyors. Size 12B–16B handles the torque and the 3"–6.5" shafts common on aggregate and mining conveyors.
- Irrigation & Water Systems — vertical turbine pumps, booster stations, and pivot drives. Bushed design allows field bore changes when repurposing motors.
- Oil & Gas Production — pump jack drives, rod pump connections, and compressor shafts. Taper-lock grip handles cyclic loading without fretting.
- Mill & Crusher Drives — hammer mills, roller mills, and jaw crushers. Size 13B–16B provides the torque capacity and shock absorption these applications demand.
- Generator Sets — engine-to-generator connections on standby and prime power installations. Fail-safe interlock keeps the gen running even if the sleeve deteriorates.
1 Flange only — taper-lock bushing, bushing bolts, and Quadra-Flex sleeve ordered separately.
2 Bushing bolt sets available as “-BOLTS” variants for each size.
3 Two flanges + one sleeve + two bushings = one complete coupling assembly.
4 Torque ratings shown are for the complete coupling assembly with JEM/N type sleeves. Hytrel sleeves increase torque capacity.
5 Max bore is determined by the taper-lock bushing, not the flange itself.
6 All Quadra-Flex components are manufactured by Martin Sprocket & Gear, Arlington, Texas, USA.
