03:02 Jan 14 

Dear Stefanie & Charles,
Thank you very much for your useful ideas. You are English native speakers, whereas English is my second language, what I said is what I learnt in books, so I need some more comments from English native speakers.
Best regards

22:37 Jan 13 

Thank you for the further context. I think that is the type of use that Charles and I are both referring to, where it is common and acceptable to use tightenings. These are countable acts of tightening - not a subsitute for fastenings as a type of thing/concrete object.

18:52 Jan 13 

in this cas it is used as a noun. Automatc screw drivers are used to fasten a number of joints with screws. In the manual of the screw driver the word "tigtenings" is used for the number of work cycles of the tool.

16:35 Jan 13 

Consider, for example, a screw that is repeatedly tightened and then removed. You could say that after many tightenings, the hole becomes enlarged and the screw becomes loose. Here is a similar case:
"Unfortunately, the plastic screw can't stand too many tightenings before it breaks"
http://forums.dpreview.com/forums/readflat.asp?forum=1010&me...

If you were determined at all costs to avoid using "tightenings", it could be done; you could say "the screw can't stand being tightened too many times". But there is nothing wrong with the statement as quoted.

16:03 Jan 13 

Generally speaking, it is true that gerunds do not have plurals. The apparent exceptions tend to be cases which are not really gerunds but words of the same form used as count nouns, such as Jack's fastening (a device that fastens something) or feeling, for example. However, gerunds can become count nouns when they refer to occasions on which an action is performed or takes place. An occasion on which you are beaten is called a beating, and children used to suffer regular beatings. In principle, if this can be done with the verb "beat", there is no logical reason why it should not be done with the verb "tighten".

"Tightenings" is a very well established usage in the sense of uterine tightenings in pregnancy, similar to, but not the same as, contractions. It is no use objecting that people shouldn't say this; they do, and they are not going to stop. The word is needed.

I suspect that you are interested in whether "tightenings" can be used in other contexts. In principle, a tightening could be an occasion on which something is tightened, such as a screw, and so you could speak of a number of tightenings. I don't see why not.

08:20 Jan 13 

...which is a perfectly valid word. And fastenings can be tightened. Maybe this is the word the writer of this document should have used?

07:14 Jan 13 

They are quite right - there is no plural form. If you can give us the sentence it comes in, perhaps we can help you construct the translated sentence so that you don't feel you are missing the terminal -s.