Sheet metal screw
A tapping screw is generally used for screwing a member to a sheet , the holes without thread at the appropriate locations has. The tapping screw does not have a metric thread like other metal screws , but is conical like a wood screw . It can usually be distinguished from this by the more compact shape and that its thread extends to the screw head.
The external thread of the sheet metal screw forms its nut thread when screwing in without machining the screwed components. The material, sheet thickness and manufacturing process all play a role in determining the diameter of the core holes . Holes made by machining or dicing can be slightly smaller than those made by forming (such as with a mandrel ). The sheet metal thickness must be greater than the thread pitch of the screw.
For sheet metal screws there are the standards DIN ISO 1478 to DIN ISO 1483.
literature
- Peter Kiehl (Ed.): Introduction to the DIN standards, Springer, Berlin 2001, pp. 378–379. ISBN 9783519263012