User login

Forgot your password?

Trueness of gauge

Coating solutions Markets Coaters Academy Press Company Glossary

Misc pages

Trueness of gauge

To ensure that a bolt rotates precisely within the thread it is necessary for both the thread dimensions of the bolt and the nut to offer enough “play” for the fastening process. This “play” is reflected in the trueness of gauge.

In practical use, trueness of gauge is guaranteed via precisely tailored tolerance systems, which also incorporate different surface coatings. If surface protection is to be applied, the threads of bolts should be produced smaller and those of nuts correspondingly larger, to ensure functional capability.

Characteristics of thread gauging

This procedure is undertaken using a DIN EN ISO 1502 gauging, which often results in problems occurring in practice, although these can be avoided if a number of aspects are taken into account:

  • “Used” gauges should be employed for the outgoing inspection, as the dimensions of “new” gauges are lower than the thread maximum (see DIN EN ISO 1502).
  • The thread should be inspected prior to application of the surface coating. If the thread gauge is difficult to apply - for example in the case of scaled or blasted surfaces - a drop of oil is permitted and helpful.
  • In the case of zinc flake coatings the surface may be scratched/loosened by the thread gauge, resulting in the “jamming” of the ring. Cleaning and re-application is recommended in this case.

A further problem occurs in the gauging of internal threads: as nuts in the bath in particular are “retaining parts”, this leads to concentration in the thread base. Although gauging may not be possible, the nuts can still be fastened securely. However, according to DIN EN ISO 10683 2014-10 ordering parties and coaters may negotiate other procedures. Regarding this, in the "Inspection of threadability of nuts with zinc flake coatings" guideline the Deutscher Schraubenverband introduced an alternative test pin that is already in use and is intended to be incorporated into a VDA regulation.

Misc pages

Curing in process
Conveyor belt oven (continuous oven)
Tray oven (continuos oven)
Chain conveyor oven
Chamber oven
Drying process
Cooling (after annealing)
Exhaust air treatment
KTL breakdown voltage
Condensed water test according to DIN EN ISO 6270-2
Sacrificial anode
Local element
Surface protection
Hot-dip galvanising
Flame spraying
Galvanic coating
Conversion layer
Dry-film coat thickness
Fastening properties
Gloss level
Artificial weathering test
Test procedures
Surface properties
Chemical resistance
Mechanical resistance
Natural weathering test
Physical properties
Passiveness, passive state
Protection, galvanic
Protection, temporary
Chromate Coating
Passivation coating
Rack coating
Bulk process
Partial production lot
Drum coating
Erichsen ball recess
Coating thickness, total
Coating thickness, local
Coating thickness, reference
Coating weight
Dry to the touch
Reference surface
Spray coating
Electroplated coating
Specific surface
Passive corrosion protection
Inorganic protective coatings
Organic protective coatings
Active corrosion protection
Forms of corrosion
Types of corrosion
Surface corrosion
Shallow pitting corrosion
Pitting corrosion
Contact corrosion
Bimetallic corrosion
Stress corrosion cracking
Hydrogen induced cracking
ISO 9001
Electro-dip painting (ETL)
Electrostatic powder spraying (EPS)
ISO 14001
Trueness of gauge
Coefficient of friction
Setting behaviour
Fastening and assembly
Kesternich test
Material effectiveness
Environmental management
Quality management
Magnetic induction measurement
Scaling protection
Powder coating
Coil coating
X-ray fluorescence analysis
Beta backscatter method
Mandrel bend test
Eddy current method (phase sensitive)
Eddy current method (amplitude sensitive)
Corrosion College
Powder sintering process
Zinc flake coatings
Dip coating process
Stone impact test
Process stages of KTL-seperation
Corrosion testing atmospheres conducive corrosion
Coat thickness and coat thickness measurement
Adhesion test according to DIN EN ISO 10683
Cross-cut test for adhesion
Thread tolerance
Pressure water jetting test
Fertiliser resistance
Anodic dip coating (ADC)
Cathodic dip coating (CDC)

Technical terms can not always be avoided. As corrosion experts, we not only want to give you comprehensive advice, we are also interested in making you a corrosion expert yourself.

The variety around the topic of corrosion and corrosion protection is also in our glossary at home: explanations from A as in Adhesion to T as in Thread tolerance. Have fun clicking through!