Berkeley S23036 External Tooth Lock Washer - 3/8 in. 410 Stainless
The Berkeley S23036 is the genuine external tooth lock washer used throughout Berkeley pump assemblies, with a 3/8 in. inside diameter and made from 410 stainless steel. It sits under the head of a bolt or under a nut, and the twisted, spring-tempered teeth around its outer edge bite into the fastener face on one side and the component on the other as the joint is tightened. Those bite points resist the small rotational creep that vibration and thermal cycling otherwise use to work a fastener loose over time.
The material choice is deliberate and worth understanding, because it is a compromise rather than an upgrade. A lock washer only works if it holds a spring temper, and the familiar 300 series stainless grades such as 304 and 316 cannot be hardened by heat treatment, so they make poor lock washers. 410 is a martensitic stainless that can be hardened, so it holds the spring while still offering far better corrosion resistance than the zinc-plated carbon steel washer found in a general hardware drawer. It is not as corrosion resistant as 316, but a plated washer in a wet pump room loses its coating, rusts, and the teeth round off - and a lock washer with dull teeth is just an expensive flat washer.
Treat these as consumables. Once the teeth have flattened out against a hard surface they will not develop the same grip again, so the sensible practice is to fit fresh ones during an overhaul rather than reusing what came off. It matters more on a pump than on most machinery: a loose fastener on a casing joint shows up first as a weep that no new seal will cure, and a loose fastener on a mounting foot quietly pulls the drive out of alignment and destroys bearings and couplings. Keep a few in the spares box, and pair stainless washers with stainless fasteners so you are not setting up a galvanic couple in a damp or salt-air installation.
Key Features
- Genuine Berkeley (Pentair Pump Group) service part
- 410 stainless steel - hardenable, so it holds spring temper while resisting corrosion
- 3/8 in. inside diameter to suit 3/8 in. fasteners
- External tooth design places the bite points on a larger diameter for greater resistance to loosening
- Holds its grip under the vibration and thermal cycling normal to pump duty
- Suited to damp, splash and salt-air environments where plated steel fails quickly
Applications
- Berkeley centrifugal pump assemblies using 3/8 in. fasteners
- Casing joints, bearing frame hardware and mounting feet
- Replacing corroded or flattened lock washers during an overhaul
- Marine, dockside and raw water installations
- Irrigation, dewatering and transfer pump service
- Pump repair shops and maintenance spares stores
Specifications
- Brand: Berkeley
- Manufacturer: Pentair Pump Group
- Manufacturer Part Number: S23036
- Part Type: Lock washer, external tooth
- Material: 410 stainless steel
- Inside Diameter: 3/8 in.
- Fastener Size: 3/8 in.
- Condition: New
Frequently Asked Questions
Q: What is the difference between external and internal tooth?
An external tooth washer carries its teeth on the outer rim, working on a larger diameter and giving more locking effect, which is why it is the usual choice under a hex head or nut. An internal tooth version hides the teeth beneath the fastener head and is chosen where marking a visible surface matters more than maximum grip.
Q: Can I substitute a split ring lock washer?
They are not equivalent. A split ring digs in at one small point, while a toothed washer spreads many bite points around the whole joint. Use whichever type the pump parts list specifies rather than whatever happens to be in the drawer.
Q: Will it mark the parts it is fitted against?
Yes, and that is exactly how it works - the teeth are meant to cut into the mating faces. Expect witness marks on paint or on a soft surface. A plain flat washer underneath will protect the finish, but you give up the locking action on that side of the joint.
Q: Do I need thread locking compound as well?
Usually not, since the two work in different places - the washer at the bearing face and the compound on the threads. Using both together is not harmful, but it makes the fastener considerably harder to release the next time the pump needs opening.
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 lock washer before you order.
CLRMarine
