When working on a technical drawing project, I couldn't find the exact dimensions of the following screw

enter image description here

In particular, I don't understand the $0.5:1$ to $\emptyset 15$ indication.

Is this screw in any DIN/ISO (maybe DIN 914 or ISO 4027) standard?


2 Answers 2


Expanded from Solar Mike's answer:

The screw is 8mm in diameter, 22mm long, has a thread every 1.25mm, and the tip is 5mm in diameter, tapered down from the full screw diameter (8mm) with 0.5(H): 1(V) tapering.


That says taper point diameter 5 to the full diameter.

It is 22 long M8

  • $\begingroup$ I'm sorry, english is not my first language. What do you mean by diameter 5 to the full diameter? The taper begins with a diameter of 8, and then for every mm down, the diameter of the taper shrinks by 0.5 mm until it has diameter 5? $\endgroup$
    – alexp9
    Sep 11, 2021 at 22:31
  • $\begingroup$ Doesn't really answer the question, specifically how the taper callout works. $\endgroup$
    – Drew
    Sep 11, 2021 at 23:13

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