My only big gripe with the current system is that tech use isent broken down into subdivisons like lores are. It seems silly that a lowly mechanic would also have the know how to fix a starship engine core.

I think it would be better if tech-use was divided into things like tech-use-Weapons, Tech-use Veihicles, Tech-use Starship.

Does anyone else think this is a good idea?

Have you seen the new rules for Repairing vehicles? Starship repair would require more than just Tech-Use. Common Lore (Adeptus Mechanicus) at the least, and maybe a starship related lore skill in a campaign centering on ground-based soldiers.

Also, the general WH40K RPG rules have been moving in a direction away from many, many, many skills, and have been consolidating them - splitting up Tech Use would be counter to this.

As Galaga said though, just because you have Tech Use doesn't mean you can automatically fix something. Other skills can and should be called into the equation, with a lack of such skills meaning negative modifiers at the least, and being entirely unable to fix it at most.

There is also the matter of scale, one man is not enough to repair even a 1km escort Destroyer's plasma drive. I don't care how skilled you are, you need a small army of Tech-Adepts plus servitors and ratings for muscle to do that kind of work.

I agree with everyone above, I think it would complicate things to have subdivisions of Tech-use, and it should be something the GM is handling on his/her side when assigning the difficulty of the task the PC is attempting to do. I think it's the kind of thing where it should be case-by-case and in view of the PC's background/history rather than having a bunch of subrules.

There were many threads on the DH forums trying to figure out just which tech-skill did what. Tech-Use, Common Lore (Tech), Trade (Technomat) and others, with various descriptions suggesting one might let you know how to operate things, one might let you maintain with rites, and one might let you actually know how to fix broken stuff, and even build things. But then examples contradicted this, and in the end tech-use seemed to be used for everything

So yeah, why not?