Calpeda 14003630000 Impeller Key - 4 x 4 x 12 mm UNI 6604
The Calpeda 14003630000 is the genuine impeller key, a parallel key measuring 4 x 4 x 12 mm made to UNI 6604 in the round-ended type A form. It is the small rectangular bar that sits half in the keyway machined into the shaft and half in the matching slot in the impeller boss, and it is the only thing actually transmitting the motor torque into the impeller. The impeller nut clamps the impeller axially; the key is what stops it turning independently of the shaft.
For a part that costs so little it carries a surprising load, and it takes that load in shock rather than steadily. Every start of a direct-on-line motor applies the full breakaway torque in a fraction of a second, and anything that momentarily jams the impeller - a stone, a rag, a piece of weed - transmits straight through this one small bar. Keys that have been overloaded or have been running in a worn keyway show rounded edges, a burr pushed up along one face, or a visible rock when the impeller is refitted. A key like that is already partway to shearing, and when it goes the impeller spins freely on the shaft, output collapses to nothing, and the keyway in the shaft is usually damaged in the process.
Fitting a new one is straightforward and worth doing on principle whenever the impeller comes off. The key should slide into the shaft keyway with light hand pressure and be a snug side fit, not a hammer fit and not loose enough to rattle. Check the keyway in both the shaft and the impeller for wear or burrs before assembly, because a new key in a spread keyway simply repeats the failure. Dimensions are what identify this part, so match 4 by 4 by 12 rather than working from a pump model name.
Key Features
- Genuine Calpeda spare part
- 4 x 4 x 12 mm parallel key to UNI 6604, round-ended type A form
- Transmits full drive torque from the shaft to the impeller
- Correctly sized for a snug side fit, so the impeller cannot rock on the shaft
- Inexpensive to replace on every impeller removal, unlike the shaft it protects
- Identified by dimension, independent of the pump model name
Applications
- Calpeda centrifugal pumps using a 4 x 4 x 12 mm impeller key
- Impeller replacement, mechanical seal work and full wet-end overhaul
- Replacing a key that is rounded, burred or has been overloaded
- Rebuilding a pump after an impeller jam or foreign object strike
- Workshop spares stock and service kits
- Marine, dockside, industrial and agricultural pump service
Specifications
- Brand: Calpeda
- Manufacturer: Calpeda Spa
- Manufacturer Part Number: 14003630000
- Part Type: Impeller key, parallel
- Dimensions: 4 x 4 x 12 mm
- Standard: UNI 6604
- Form: Type A, round ended
- Quantity Used: One per impeller
- Condition: New
Frequently Asked Questions
Q: What does the type A round-ended form mean in practice?
It means both ends of the key are radiused rather than square, so it drops into a keyway that was cut with an end mill and has rounded ends of its own. A square-ended key will not seat fully in that kind of slot and ends up bearing on its corners.
Q: Should the key be a tight drive fit into the slot?
No. It should be snug across the width but slide in by hand. A key driven in with a hammer distorts and can spread the keyway, and it also makes the next removal far harder than it needs to be.
Q: Can I file a longer key down to length?
It is possible but rarely wise. Cutting leaves square ends that will not sit in a rounded keyway, and hand-filed faces are seldom parallel enough to bear evenly. A key that bears on part of its face carries the load on that part alone.
Q: My old key came out with a twist in it. What does that indicate?
It indicates the key has been yielding under load, usually because the keyway has worn or the impeller has been running slightly loose. Fit a new key by all means, but inspect both keyways carefully first - a twisted key is a symptom, not the disease.
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 key size before you order.
CLRMarine
