

The Graco 100681 Nut is a genuine OEM jam hex nut designed for secure locking of fittings and components in Graco drum and pump systems.
The Graco 100681 is a thin jam hex nut commonly used to lock fittings or components against vibration. It appears in multiple Graco assemblies; see verified machines below and always confirm with your equipment’s parts list.
Confirmed usage where 100681 is listed in the official parts breakdown:
Also used across select Graco drum/supply and pump systems wherever a jam hex nut of matching spec is called out. If your sprayer/system manual lists 100681, this is the correct replacement.
| Graco Part # | 100681 |
|---|---|
| Type | Nut, Jam / Hex (thin lock nut) |
| Typical Thread | 5/8-11 UNC (verify per your manual) |
| Common Use | Locks a fitting or primary nut to resist loosening from vibration |
| Material | Steel (finish may vary by assembly) |
| Question | Answer |
|---|---|
| What exactly is the Graco 100681 Nut? | It’s a jam hex nut (thin profile) used as a lock nut in various Graco assemblies to prevent loosening. |
| Does it fit my airless sprayer? | If your model’s manual lists 100681 in the parts breakdown, then yes. If not listed, use the specified nut from your manual. |
| Is the thread always 5/8-11 UNC? | That size is commonly referenced, but always verify the thread spec called out for your exact assembly. |
| Can I substitute a standard full-height nut? | Not recommended. A jam nut has a thinner profile designed to lock against a primary nut or fitting without altering stack height. |
| Any installation tips? | Clean threads, torque per the manual, and use a second wrench to hold the primary fitting while tightening the jam nut to lock it securely. |