What the Graco 866212 Square Key Is For
The Graco 866212 Key, Square, 3/16 x 1.35 is a precision square drive key used in mechanical drive systems to secure rotating parts like sheaves, gears, and couplings on sprayers and fluid drive motors where a 3/16″ square keyway is needed. It’s a critical alignment and torque transfer component.
Compatible Machines
This square key is referenced as a service part in the internal parts breakdowns of several Graco units that use keyed drive shafts or gear assemblies:
- Airlessco / Graco TS1500 Series Airless Sprayer — motor/gear drive assemblies include square key 866212.
- Graco Airless Sprayers with keyed gear drives — units using square drive connections on sheaves and couplings.
- Graco Sprayers with Internal Gear/Motor Assemblies — typically older or industrial models where keyed shafts and gear sheaves require this key.
Specifications & Details
| Part Number | 866212 |
| Type | Square drive key |
| Dimensions | 3/16″ (width) x 1.35″ (length) |
| Use | Torque transfer on keyed shafts and couplings |
Frequently Asked Questions
It fits into a keyway on a shaft and mates with a corresponding keyed hub, coupling, or sheave to prevent rotation slippage and transfer torque reliably.
Square keys are not wear parts per se, but they can shear or deform under extreme overload; if you replace gears or hubs, verify the key’s condition.
This key fits applications with a **3/16″ wide keyway and 1.35″ length**. Always check your machine’s parts diagram or service manual to confirm the key size and use.
