So my tech priest has picked up Trade (Armourer) to make guns and armour. But now I want to make common tech items, too: magnoculars, vox-thieves, that kind of thing. But there's no tech skill for it. Trade (Wright) is for buildings and vehicles. Trade (Technomat) is specifically not for building things. None of them cover mundane tech items, even .

Should there be another Trade skill, and if so what should it be called? Or does this fall under the almighty Tech Use skill? Or should Trace (Wright) be expanded to cover it? Any ideas?

Another few that are missing:

Trade (Servitors)
Trade (Implants)

if you want to make i sevitor i would say you should make some medicae, some amourer and som smith rolls to see if it has worked.

and if you want to make new items make som tech-use and amourer/smith rolls, IF the person have som plans over what he wants to make

I don't see why you couldn't make up something like Trade (Electrician) or something along those lines. Then combine it with smithing and armourer.

As far as the RAW goes, "Tech Use" is the skill for not only used for repairing but also creating technological items (see page 108 Core rules).