I am reading Heidegger, and he uses Gestell, which is frame, but he uses it as a verb, "enframing" (which translates to Umrahmung). This is rooted in "Rahmen".
Which is the best word for the phrase "enframing is danger" ?
Heidegger is known to be extremely creative with the usage of terminology, he commonly takes standard terms and puts them in a specific contextual meaning in his works, but with a strong tendency to neglect the definition. Sometimes, you are actually better off to just call the term 'x' instead of looking for any meaning in the word itself outside of Heidegger's works. There is a saying that goes like:
Heidegger hatte die ärgerliche Gewohnheit, deutsch zu sprechen
(Leaving the annoying task of being expected to understand what he meant to the poor German-speaking world)
I am not sure if it makes a lot of sense to translate such terms in Heidegger's works - And if yes, you should use standard translations - Typically, Gestell in Heidegger's works is translated to enframing (the substantive). So no, he doesn't use it as a verb. Gestell does not have a closely associated verb in German (so it is a bit misleading that translators seem to have agreed upon a substantiation of a verb in the English translations).
So your translation should simply be
Das Gestell ist eine Gefahr
(Which doesn't make a lot of sense without context to me)