Decision Notes
What to confirm first.
- M6 washer quick size: 6.4 mm ID, 12 mm OD, 1.6 mm thickness is a common DIN 125 / ISO 7089 normal-series reference.
- M8 washer quick size: 8.4 mm ID, 16 mm OD, 1.6 mm thickness is commonly checked before matching M8 bolts and nuts.
- M10 washer quick size: 10.5 mm ID, 20 mm OD, 2.0 mm thickness is a frequent procurement check for DIN 125 flat washers.
- M12 washer quick size: 13 mm ID, 24 mm OD, 2.5 mm thickness is commonly used as a first RFQ reference.
- Confirm standard, material, finish, hardness, and packing before ordering washers by size alone.
Buyer Guide
Flat washers look simple, but washer dimensions affect bolt fit, load distribution, surface protection, and packing accuracy. Buyers often search for M6 washer size, M8 washer dimensions, M10 flat washer OD, or M12 DIN 125 washer thickness because they need a quick specification check before sending an RFQ.
Quick reference for common normal-series metric flat washers: M6 washers are commonly specified around 6.4 mm inside diameter, 12 mm outside diameter, and 1.6 mm thickness. M8 washers are commonly specified around 8.4 mm inside diameter, 16 mm outside diameter, and 1.6 mm thickness. M10 washers are commonly specified around 10.5 mm inside diameter, 20 mm outside diameter, and 2.0 mm thickness. M12 washers are commonly specified around 13 mm inside diameter, 24 mm outside diameter, and 2.5 mm thickness. Always confirm the exact standard, tolerance, and series required by the drawing or destination market.
DIN 125 and ISO 7089 are both widely used for metric flat washers, but buyers should not treat every washer marked by size alone as identical. The RFQ should confirm the standard, nominal thread size, inside diameter, outside diameter, thickness, material, surface finish, hardness expectations, and whether washers should be supplied together with matching bolts and nuts.
For stainless assemblies, SS304 and SS316 flat washers are often selected for corrosion resistance and clean appearance. SS316 is usually preferred when moisture, outdoor exposure, chemical contact, or marine-adjacent conditions are expected. For general industrial or construction use, carbon steel washers with zinc plating or other finishes may be more cost-effective.
When sourcing washers as part of a bolt set, confirm the matching bolt diameter, nut standard, washer quantity per set, packing method, and whether the project needs inspection documents. A clear RFQ reduces the risk of receiving washers with the right nominal size but the wrong thickness, material, or finish.
Use this guide as a starting point for procurement decisions, then confirm the final washer specification against your drawing, assembly load, environment, and target standard before ordering.
FAQ
Questions buyers usually ask next.
What is the common M10 flat washer size?
A common normal-series M10 flat washer reference is about 10.5 mm inside diameter, 20 mm outside diameter, and 2.0 mm thickness. The final requirement should still follow the drawing or specified standard.
Are DIN 125 and ISO 7089 flat washers the same?
They are closely related metric flat washer standards used in many sourcing requests, but buyers should still confirm the exact standard, washer series, dimensions, tolerance, material, and finish required by the project.
Should washers be quoted together with bolts and nuts?
For assembly projects, it is often better to quote washers with matching bolts and nuts so thread size, material, grade, finish, and packing can be checked as one set.
Which material is better for flat washers, SS304 or SS316?
SS304 is suitable for many general corrosion-resistant assemblies. SS316 is usually preferred for moisture, outdoor, chemical, or marine-adjacent environments where stronger corrosion resistance is needed.
What should a washer RFQ include?
Include the standard, nominal size, ID, OD, thickness, material, finish, quantity, packing method, matching fasteners, and any certificate or inspection requirements.