Notes on bolted connections with self tapping screws - AH00.00-P-0007-01SF
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General:
Terms:
"Self-forming" is the generic term and includes both "thread-rolling" 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 thread has to be cleaned using compressed air; wear safety glasses while doing so.
Repairs and replacements:
- The reuse of an existing or another used thread rolling screw is permissible if the screw is undamaged.
- It is permissible to fit a new thread rolling screw into a screw-in thread that already exists.
- A thread-rolling 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 rolling screw.
With safety-relevant components (e.g. front axle integral carrier), no standard screws/bolts may be used.
Only self-tapping screws may be installed here.