Disc spring tolerances are specified in four places: overall height, thickness, load and diameter. Each one lands somewhere different in your assembly. Height and thickness stack up over a column of springs, diameter decides how the spring sits on its guide, and load tolerance decides whether the force you calculated is the force you get. SCHNORR disc springs are manufactured to DIN EN 16983 for quality and dimensions and DIN EN 16984 for calculation.
Most disc spring problems are not calculation errors. They are tolerance surprises: a stack that will not fit the pocket, a preload that comes out low, a spring that rattles on its guide. Reading the tolerance set properly heads off all three.
Overall height
Overall height is the free height of the single spring, and it is the tolerance that multiplies. In a series stack, individual variations add up, so a column of eight springs carries eight times the scatter. If the housing pocket was dimensioned from a nominal calculation, that is where the interference appears.
Practical approach: budget the disc spring stack height from the tolerance extremes rather than the nominal, and make one abutment adjustable if the assembly allows.
Thickness
Thickness drives force. It also decides the material group: cold rolled carbon spring steels C67S and C75S are used for group 1 springs below 1.25 mm, above 1.25 mm the material is 51CrV4 in rolled condition, and above 6 mm it is used in forged form. So a thickness change on a drawing revision can quietly change the material and the process.
Load
Load tolerance is the one to check when the application is a preload rather than a travel. Spindle preload, valve set force and torque limiting all depend on the force being repeatable, and it is the load tolerance, not the height tolerance, that governs. Where a tighter band is needed, that is a conversation rather than an assumption.
Diameter
Inside and outside diameter tolerances control how the spring sits against its guidance. That connects straight to the guidance rules, which are worth writing on the drawing rather than leaving to assembly:
- A guide element is needed to prevent lateral movement.
- Inside guidance on a bolt or shaft is preferred, though outside guidance is acceptable.
- Guides and abutments should be hardened to at least 60 HRC with a minimum case depth of 0.8 mm, where possible.
- The guide surface should be smooth and, if possible, ground.
- For static applications, guides can be unhardened.
The standards on your drawing may be out of date
Disc springs are manufactured to DIN EN 16983 for quality requirements and dimensions and DIN EN 16984 for calculation. These replaced DIN 2093 and DIN 2092 respectively. Older drawing packs still carry the old numbers, and both refer to the same family of parts, so a DIN 2093 replacement callout on a legacy drawing does not need a redesign, only an updated reference.
A five line drawing note that prevents most problems
- Spring reference and standard, using the current DIN EN numbers.
- Material and surface finish.
- Required force at a stated installed height, with the acceptable band.
- Stack arrangement: how many in series, how many in parallel, and the assembly order.
- Guidance and abutment requirements, including hardness.
Add those five lines and the part can be quoted, made and inspected against the same intent. Standard sizes are in the Product Finder, and CAD drawings are available for the layout work.
- Disc spring tolerances are defined for overall height, thickness, load and diameter.
- SCHNORR disc springs are manufactured to DIN EN 16983 (quality requirements and dimensions) and DIN EN 16984 (calculation).
- DIN EN 16983 and 16984 replaced DIN 2093 and DIN 2092 respectively.
- C67S and C75S carbon spring steels are used for group 1 disc springs below 1.25 mm thickness.
- 51CrV4 is used in rolled condition above 1.25 mm, and in forged form above 6 mm.
- A guide element is required to prevent lateral movement, with inside guidance on a bolt or shaft preferred.
- Guides and abutments should be hardened to a minimum of 60 HRC with a minimum case depth of 0.8 mm, and can be unhardened for static applications.
Frequently asked questions
Which tolerances are specified for disc springs?
Overall height, thickness, load and diameter.
Which standards apply to disc springs today?
DIN EN 16983 for quality requirements and dimensions, and DIN EN 16984 for calculation. They replaced DIN 2093 and DIN 2092.
Why does thickness change the material?
Cold rolled carbon spring steels C67S and C75S are used for group 1 springs below 1.25 mm. Above 1.25 mm, 51CrV4 is used in rolled condition, and above 6 mm in forged form.
Which tolerance matters most for a preload application?
Load tolerance. Preload applications depend on repeatable force, so the load band governs rather than the height band.
What should a drawing say about guidance?
That a guide element is required to prevent lateral movement, that inside guidance on a bolt or shaft is preferred, and that guides and abutments should be hardened to at least 60 HRC with a minimum case depth of 0.8 mm and a smooth, ideally ground surface.