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Screws · Pan Head Screws

SEMS Screws with Captive Conical Spring Washers

8 catalogued sizes, dimensioned to DIN 6900-5 Z9 and DIN 6908. Pick any row and the technical drawing redraws to it.

SEMS Screws with Captive Conical Spring Washers to DIN 6900-5 Z9 and DIN 6908 are catalogued in sizes M2.5 to M12, with pitch 0.45-1.75 mm, thick 0.5-3 mm. 8 sizes are held in the table below, and the technical drawing redraws to whichever row you select.

Standard
DIN 6900-5 Z9 and DIN 6908
Size range
M2.5-M12
Pitch
0.45-1.75 mm
Thick
0.5-3 mm
Catalogued sizes
8

Dimensions are nominal values from the governing standard. Confirm the tolerance class for your application before ordering.

SEMS Screws with Captive Conical Spring Washers technical product image

Applications & Industries

SEMS Screws with Captive Conical Spring Washers are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M2.5 to M12.

Industries that specify SEMS Screws with Captive Conical Spring Washers

  • Instrument housings Small fasteners where repeated cover removal must not lose the washer.
  • Control panels Captive spring-washer screws on covers and electrical equipment.
  • Light machinery Joints that settle slightly during service and need maintained contact.
  • Appliances High-volume assembly with a washer that cannot fall away from the screw.
  • Food, pharma & cleanroom Stainless assemblies that are washed down, where the finish matters as much as the strength.
  • Machine building & OEM The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.

Typical applications

  • selecting the washer inside diameter, outside diameter and thickness together
  • combining a machine screw with a captive conical spring washer
  • using limited spring travel to maintain light joint contact
  • keeping the washer attached during panel and cover service
  • joints where the property class is stated on the drawing
  • clamping two machined faces to a calculated preload

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.
High load
Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
Torque and preload
The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.

Where to use something else

  • Do not use the conical spring washer as a structural flat washer or as a wedge-lock pair.
  • Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.

Full application guide: where SEMS Screws with Captive Conical Spring Washers are used, how to specify them, and the cases they are wrong for

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.

Sends the selected values to the quote form below.

Request a Quotation for SEMS Screws with Captive Conical Spring Washers

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

Request a Quotation

Specification
Business Information

Dimensions & Specifications (DIN 6900-5 Z9 and DIN 6908)

Every row below is a starting point for the customizer above — pick any size and the drawing will redraw to that row.

Thread sizePitch (mm)Washer inside diameter (mm)Washer outside diameter (mm)Washer thickness (mm)Material optionsReference standard
M2.50.452.25~2.355.7~6.00.5steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M30.52.75~2.856.64~7.00.6steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M40.73.6~3.728.64~9.01.0steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M50.84.55~4.6710.57~11.01.2steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M61.05.5~5.6213.57~14.01.5steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M81.257.4~7.5517.57~18.02.0steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M101.59.3~9.4522.48~23.02.5steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908
M121.7511.0~11.1828.48~29.03.0steel or A2 stainlessDIN 6900-5 Z9 and DIN 6908

SEMS Screws with Captive Conical Spring Washers conform to DIN 6900-5 Z9 and DIN 6908. As screws, they are specified by the dimensions in the table below; this page also covers materials, finishes and typical uses.

What Are SEMS Screws with Captive Conical Spring Washers?

SEMS Screws with Captive Conical Spring Washers are screws defined by DIN 6900-5 Z9 and DIN 6908. They are selected by thread size and the dimensional characteristics shown below, and are available in a range of materials and finishes to suit the application and environment.

Materials & Finishes

Common materials include carbon steel (typically zinc plated or hot-dip galvanized), alloy steel in property classes 8.8, 10.9 and 12.9, and stainless steel A2 (304) or A4 (316) for corrosion resistance. Specify the material, property class and surface finish appropriate to your load and environment.

Pricing

SEMS Screws with Captive Conical Spring Washers are supplied to order. Pricing starts from approximately US$0.060 per piece for standard sizes in carbon steel; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.

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

What is the controlling standard for SEMS Screws with Captive Conical Spring Washers, and what drive do they take?

SEMS Screws with Captive Conical Spring Washers are manufactured to DIN 6900-5 Z9 and DIN 6908 and use a cross recess (Phillips/Pozi) drive. The dimensional values on this page follow that standard.

Which sizes of SEMS Screws with Captive Conical Spring Washers does Engineering Hardware supply?

The table on this page lists 8 sizes for SEMS Screws with Captive Conical Spring Washers, ranging from M2.5 to M12. Sizes outside the table can be quoted on request.

In which materials are SEMS Screws with Captive Conical Spring Washers supplied?

SEMS Screws with Captive Conical Spring Washers are supplied in alloy steel (typically 10.9 / 12.9 for socket screws), carbon steel and stainless A2 / A4, with finishes including zinc plating, hot-dip galvanizing and black oxide. Choose material and finish to suit the load and the service environment for SEMS Screws with Captive Conical Spring Washers.

How do I request a quotation?

Use the parametric drawing on this page to set the exact configuration (size, material, finish) and click "Request this configuration" — a specialist from Engineering Hardware will respond within one business day.