AMT 1784-001-00 Impeller Lock, 7/16-20 Stainless Acorn Nut
The AMT 1784-001-00 is the genuine impeller lock — a 7/16-20 stainless steel acorn nut that threads onto the end of the shaft and holds the impeller in place. The acorn (domed) form is not decoration. The closed dome covers the exposed shaft thread, which keeps liquid out of it, stops corrosion building in the thread roots, and gives the nut a smooth profile that will not catch rag or fibrous debris passing through the suction.
This one fastener carries every bit of load the impeller generates. It has to hold the impeller hard against its shoulder so the two turn as one unit, and it has to do that while the impeller is being pushed backwards by discharge pressure and hammered by anything solid that comes through. If the nut loosens, the impeller starts to move on the shaft — it fretts the shaft end, wears the drive key or flats, goes out of balance, and can eventually shear the shaft or wreck the casing.
Stainless steel is specified because this nut sits permanently in the pumped liquid at the wettest, most exposed point in the pump. Replace it rather than reusing one that has been cross-threaded, galled, or rounded off by a badly fitting spanner, and tighten it to the value in your manual — guessing is how impellers come loose. Listed for AMT models 4897, 4906 and 4907 high-head pedestal pumps.
Key Features
- Genuine AMT (Gorman-Rupp) service part — correct thread and seating form
- Stainless steel construction for permanently wetted, exposed duty
- 7/16-20 thread, acorn (domed) form
- Closed dome shields the shaft thread from corrosion and sheds rag and fibrous debris
- Holds the impeller hard to its shoulder so the assembly turns as one
Applications
- AMT 4897 high-head pedestal pumps
- AMT 4906 high-head pedestal pumps
- AMT 4907 high-head pedestal pumps
- Fitted with every impeller replacement
- Marine, dockside, dewatering and general water transfer service
Specifications
- Brand: AMT (Gorman-Rupp)
- Manufacturer Part Number: 1784-001-00
- Part Type: Impeller lock nut
- Style: Acorn (domed) nut
- Thread: 7/16-20
- Material: Stainless steel
- Quantity Used Per Pump: 1
- Condition: New
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct part before you order.
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