What are the different uses of caulking

The screw lock prevents a screw connection from loosening

There are different ways to secure a screw connection

Screw locking against loosening of the connection.

There are three types of backup:
  • Setting protection: Setting protection increases the elasticity of the connection and thus compensates for subsidence. The pre-tensioning force is largely retained, thus counteracting any loosening of the connection. The loosening of the connection in the event of forced relative movements of the components cannot be prevented.
  • Loose protection: They allow partial loosening, but prevent the connection from being dismantled on its own.
  • Loosening locks: They prevent the connection from loosening on its own.

- see also DIN 25201
Web tip: Wickipedia article screw locking

Pair of wedge lock washers

The washers have radial ribs on the outside and wedge surfaces on the inside, the pitch of which is always greater than the pitch of the thread. The washers, glued in pairs, are placed under the screw head and / or nut. Due to the radial ribs, a form fit occurs when tightening. The pair of discs is now firmly in place and movements are only possible between the wedge surfaces. Even the slightest rotation in the loosening direction increases the clamping force due to the wedge effect, the screw thus secures itself.

  • Screws M3 - M76 and 1/4 "- 3"
  • Suitable for high-strength screws up to quality 12.9 (see DIN 25 201)
  • Available in stainless steel 1.4404 (VA)
  • Can also be used with the use of lubricants
  • Special wedge lock washers for HV screw sets according to DIN EN 14399-4 and DIN EN 14399-8 are available
  • Junker vibration test according to DIN 65151 passed
Category: Anti-rotation device

Schnorr washer

Spring-loaded washer between head and workpiece. The disc is toothed on the top and bottom. The teeth dig into the workpiece surface and form a form fit. Therefore, the surface of the screw and workpiece is of crucial importance.

Category: Anti-rotation device

Polyamide washer

The polyamide washer is placed between the head and the workpiece. It deforms and presses into the cavity between the screw shaft and the bore. It forms a resilient element. During assembly, the panes behave plastically up to a certain point; if this point is exceeded, they assume an elastic behavior.

  • Temperature resistance
    • static: -60 ° - + 120 ° degrees
    • dynamic: -60 ° - + 80 ° degrees
  • For hexagon bolts: M3 - M52
  • For cylinder head screws: M4 - M24
  • Noise dampening
  • Isolating effect
Category: Loss insurance

Polyamide washer with toothed ring

The polyamide washer is placed in the toothed ring. The screw is pushed through and the nut is put on. The polyamide washer deforms under the high pressure of the nut, but can only spread to the metal collar of the toothed ring. Now the polyamide flows into the recesses of the toothed plate ring up to the through hole of the screw and into the screw thread. The mother rests on the toothed plate ring. The polyamide washer still has enough elasticity to prevent the screw from unscrewing.

  • Any nut from M4 - M24
  • Suitable for screws of higher strength
  • Can absorb any desired bolt force
  • Sealing effect
  • Damping effect
Category: Loss insurance

DSL double backup

DSL double fuse is a plastic washer made of polyamide with an injected toothed metal ring. The curved teeth penetrate the workpiece and nut, forming a force-fit connection. The polyamide also creates a preload and at the same time seals the connection by penetrating the screw hole and thread.

  • For hexagon screw / hexagon nut M5 - M30
  • For screws up to quality 12.9
  • High tightness of the screw connection
  • Safe electrical connection
Category: Loss insurance

Lock washer with ribs

On both sides of the disc there are ribs that have a circular segment-shaped cross-section. The pretensioning force pushes these ribs into the screw head and the contact surface. The resulting form fit and the fact that the angle between the circle segments and contact surfaces ("W" in the picture) is greater than the angle of the pitch of the thread prevents the connection from loosening.

Category: Anti-rotation lock

Spring washers DIN 6796

The spring washer has a slightly conical shape like a disc spring. Due to their spring action, tensioning disks have sufficient preload for short and axially loaded screws in order to compensate for settling phenomena in the axial direction. They do not offer any protection for loosening mechanisms in the radial direction.

Category: Setting protection

The following elements were used as security elements. However, they only have very poor security properties, if at all, and are only listed here for the sake of completeness.


Tip for do-it-yourselfers among them:

It is summer time, the gardening calls and one or the other is planning to build a small structure in the form of a garden shed or a terrace. The special conditions that apply to an outdoor project must be observed here. The woods used such as pine, larch, Bangkiraietc. require the right lanyards. Stainless screws should always be used outdoors. There are also special terrace screws made of stainless steel. The end of the thread, with which the screw dips into the wood, has a particularly pointed shape so that it is easy to grip even in hardwood. In addition, the terrace screws have a second thread in front of the screw head so that the components to be connected remain permanently connected.
I hope you enjoy building.

Author: Uwe Koerbitz

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