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Washers · DIN 125 A

DIN 125 A PTFE Flat Washers Specification

Dimensional table, tolerance classes and the DIN / ISO / ASME parts that supersede or match this standard.

DIN 125 A specifies the dimensions and tolerances for ptfe flat washers. The full dimensional table is reproduced below, followed by the DIN, ISO and ASME parts that match or supersede it.

Standard
DIN 125 A
Product
PTFE Flat Washers
Governing standards
DIN 125 A

Equivalence between national standards is dimensional, not always metallurgical. Check the property class separately when substituting.

DIN 125 A PTFE Flat Washers Specification reference image

DIN 125 A is the standard cited for ptfe flat washers. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.

DIN 125 A — Scope

The table below lists the dimensions catalogued for ptfe flat washers under DIN 125 A. The scope of DIN 125 A itself is not summarised here — where a figure matters, confirm it against the published document.

Tolerance & Product Grades

Product grade is a concept from dimensional fastener standards and does not apply to DIN 125 A. Tolerances for this part are the limits shown against each dimension in the table.

Dimensions Specified by DIN 125 A

Thread sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness s (mm)MaterialTemperature range (deg C)Reference standard
M33.270.5PTFE-200 to +260DIN 125 A series
M44.391.0PTFE-200 to +260DIN 125 A series
M55.3101.0PTFE-200 to +260DIN 125 A series
M66.4121.5PTFE-200 to +260DIN 125 A series
M88.4162.0PTFE-200 to +260DIN 125 A series
M1010.5202.0PTFE-200 to +260DIN 125 A series
M1213242.5PTFE-200 to +260DIN 125 A series
M1617303.0PTFE-200 to +260DIN 125 A series
M2021373.0PTFE-200 to +260DIN 125 A series

Companion Standards

A complete specification for ptfe flat washers normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. DIN 125 A is one of them, not all of them.

When to Specify DIN 125 A

DIN 125 A is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.

Custom manufacturing · Made to drawing

Need a washer to this standard in a non-standard size?

Parts built to DIN 125 A are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by stamping or punching.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

Custom washer manufacturingSend a drawing

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Dimensioned line drawing of M3 PTFE Flat Washers to DIN 125 A. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.
Inner diameter d1 (mm)
3.2
Outer diameter d2 (mm)
7
Thickness s (mm)
0.5
Material
PTFE
Temperature range (deg C)
-200 to +260
Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (DIN 125 A)

Thread sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness s (mm)MaterialTemperature range (deg C)Reference standard
M33.270.5PTFE-200 to +260DIN 125 A series
M44.391.0PTFE-200 to +260DIN 125 A series
M55.3101.0PTFE-200 to +260DIN 125 A series
M66.4121.5PTFE-200 to +260DIN 125 A series
M88.4162.0PTFE-200 to +260DIN 125 A series
M1010.5202.0PTFE-200 to +260DIN 125 A series
M1213242.5PTFE-200 to +260DIN 125 A series
M1617303.0PTFE-200 to +260DIN 125 A series
M2021373.0PTFE-200 to +260DIN 125 A series

Applications & Industries

What PTFE Flat Washers are specified for, industry by industry. Stocked from M3 to M20.

Industries that specify PTFE Flat Washers

  • Chemical & process Chemically resistant seating under a fastener.
  • Food & pharma equipment Non-marking, non-contaminating washers in washdown areas.
  • Electrical & electronics Insulating and isolating fixings in panels and boards.
  • Timber & construction Large-diameter washers that stop pull-through in softer material.
  • Rotating & vibrating plant Spring, tooth and wedge types that maintain or lock bolt tension.
  • Steel fabrication Spreading load under a head or nut and protecting the surface finish.

Typical applications

  • separating dissimilar metals to break a galvanic cell
  • protecting a soft or finished surface under a head
  • insulating a fastener electrically from the panel
  • protecting a painted or plated surface under a turned nut
  • maintaining bolt tension in a joint that settles
  • spreading clamp load over a soft or oversized bearing face

Service conditions to specify against

Marine and coastal
Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
Hardness matters
Under a high-strength bolt a soft washer embeds into the joint and preload is lost — specify a hardened washer for structural bolting.

Full application guide: where PTFE Flat Washers are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Can I substitute DIN 125 A for the corresponding DIN standard on a drawing?

On modern drawings the ISO standard is the master reference; the older DIN equivalent is a cross-reference. For most dimensional purposes the parts are interchangeable, but check tolerance grades and the head height — these are the most common points of divergence.

Which edition of DIN 125 A does this table follow?

The table reproduces the dimensions we supply ptfe flat washers to. We do not publish an edition year against it, so where the edition is contractually significant, cite the edition you require on the enquiry and we will confirm it against the table before quoting.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.