Bonded Sealing Washers are used primarily for load distribution and anti-loosening under a bolt or nut. This page lists the industries and assemblies where they are specified, the selection criteria that matter for each application, installation practice, and the cases where a different fastener type is the correct choice. Parts are supplied to Trade series (bonded seal washer, Dowty pattern). Stocked across roughly M4 to M36, they cover general to heavy-duty work.
Typical Applications for Bonded Sealing Washers
The most common settings where these are specified:
- Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.
- Bolted structural joints: spreading load over soft or oversized holes and protecting the surface.
- Vibration applications: spring and serrated types that maintain tension under cyclic load.
- Timber & soft materials: large-OD types that prevent pull-through.
- General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
How to Specify Bonded Sealing Washers for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M4–M36; check the full table below for the exact dimensions of each size.
- Type & OD: Select flat for load spreading, spring/serrated for anti-loosening, or fender/large-OD for soft or oversized holes.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This is a trade-series article rather than one covered by a published dimensional standard, so dimensions can differ between manufacturers. Quote the dimensions you need — or the part you are replacing — rather than a standard number.
Installation & Assembly Practice
- Place the washer under the rotating element (usually the nut) so tightening does not score the surface.
- Chamfered-hole side of a hardened washer faces the bolt head fillet.
- On serrated-flange hardware, do not add a plain washer — it defeats the serrations.
Common Selection Mistakes with Bonded Sealing Washers
- Relying on a spring washer for locking on class 8.8+ joints — at high preload it flattens and adds nothing.
- Choosing an OD too small for soft material, so the head pulls through or embeds.
Where Bonded Sealing Washers Are Not the Right Choice
A washer does not replace a locking feature on its own in severe vibration, and a spring washer adds little clamp on high-strength joints.
Custom manufacturing · Made to drawing
Need a bonded sealing washers outside the standard range?
Bearing area is usually the reason for a special washer: a larger outside diameter to spread load into a softer material, or a thicker section to resist dishing. Made by stamping or punching.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
