GENIE 109940.0001.S, SPRKT,50T,3/8P,3/4B,SVCE
The Genie 109940.0001.S is an OEM replacement chain sprocket designed for Genie commercial door operators. Featuring 50-Tooth #35 Chain Sprocket, 3/8 inch Pitch, 3/4 inch Plain Bore, Service Replacement, this part meets Genie factory specifications for reliable drivetrain performance. Manufactured from carbon steel sprocket body; plain bore finish suitable for set screw retention; no special outer diameter coating on this variant to withstand commercial duty cycling. Key dimensions: 50 teeth, 3/8 inch pitch (#35 chain), 3/4 inch bore, pitch diameter approximately 5.97 inches. Mounting method: Plain 3/4 inch bore; set screw retention; no keyway.
Key Features
- 50-tooth #35 ANSI chain sprocket rated for 3/8 inch pitch chain
- 3/4 inch plain bore sized for direct shaft installation in the field
- Plain bore with set screw retention - no keyway machining required
- Service replacement part for Genie commercial door operator drive trains
- Carbon steel construction for durability in commercial cycling applications
- Distinct variant from keyway-equipped 50T 3/4 inch bore part 108181 - not interchangeable
Compatibility Guide
- GCL-MH
- GCL-MJ
- GCL-T
- GCL-GT
- GCL-GH
- GCL-Fire
| Feature | Specification |
|---|
| Model | Genie 109940.0001.S |
| Item Type | Chain Sprocket |
| Materials | Carbon steel sprocket body; plain bore finish suitable for set screw retention; no special outer diameter coating on this variant |
| Dimensions | 50 teeth, 3/8 inch pitch (#35 chain), 3/4 inch bore, pitch diameter approximately 5.97 inches |
| Mounting | Plain 3/4 inch bore; set screw retention; no keyway |
Frequently Asked Questions
Q: Does this sprocket include a keyway for positive shaft locking?
A: This sprocket uses a plain bore with set screws for shaft retention. It does not include a keyway, so rotational lock relies entirely on the set screw clamping force against the shaft. For applications requiring a positive rotational lock, refer to part 108181, which is the 50-tooth, 3/4 inch bore sprocket with a keyway.
Q: Is this sprocket interchangeable with Genie part numbers 108173 or 108181?
A: No. Although all three are 50-tooth #35 sprockets, part 108173 has a 1 inch bore with a keyway, part 108181 has a 3/4 inch bore with a keyway, and part 109940.0001.S has a 3/4 inch plain bore with no keyway. These differences make them non-interchangeable, so confirm your shaft diameter and keyway requirements before ordering.
Q: What chain pitch is required for this sprocket?
A: This sprocket is designed for ANSI #35 chain, which has a 3/8 inch pitch. Using it with #25 (1/4 inch pitch) or #41 (1/2 inch pitch) chain will result in improper meshing, accelerated wear, and potential operator failure. Always match the chain pitch to the sprocket specification.
Q: What does the 'Service' designation mean in this part number?
A: The 'Service' designation indicates this part is intended for field service and replacement installations. It typically means the sprocket ships ready for direct installation on an existing shaft using set screws, without requiring broaching or additional machining for a keyway.
Q: What maintenance is recommended for this replacement sprocket?
A: Carbon steel sprockets should be inspected regularly for tooth wear, hooked or pointed tooth profiles, and set screw tightness. Because this plain bore variant relies on set screws rather than a keyway, periodically check that the set screws remain torqued to specification to prevent shaft slippage during operation.
