Notes on bolted connections with self tapping screws - AH00.00-P-0007-01SF

General: 

Terms: 

"Self-forming" is the generic term and includes both "thread-forming" and "thread-cutting". Only thread forming screws of the globally applicable "TAPTITE" standard are dealt with in the following.

Properties: 

Thread forming screws create a screw-in thread in prefabricated core holes, usually by means of beveled crests.

The screw-in threads that are created by thread-forming screws can accommodate screws with ISO metric threads (standard screws) without problems.

Self-tapping screws are automatically centered when they are first manually screwed in.

The screw-in threads must be cleaned with compressed air; safety glasses must be worn when doing so.

Repairs and replacements: 

• The reuse of an existing or another used thread rolling screw is permissible if the screw is undamaged.
• The assembly of a new thread rolling screw in a screw-in thread that already exists is permissible.
• A thread-forming screw may be replaced with a new or used standard screw. The length of the standard screw must be three threads (tapping point) smaller than the length of the originally installed thread forming screw.

With safety-relevant components (e.g. front axle integral carrier), no standard screws/bolts may be used. Only the self-tapping screws can be installed here.