I'm working on a Tinker Archetype Alchemist and while going through my Knowledge list I had a sudden realization. For someone who can make constructs and focuses on the clockwork subtype why doesn't the Alchemist Tinker get Knowledge (Engineering) as a skill?
It just seems odd to me, is all. After all, according to Knowledge (Engineering): (buildings, aqueducts, bridges, fortifications); This is the most important skill with regard to technological subjects. Knowledge (engineering) can be used to identify a robot’s abilities and weaknesses. Knowledge (engineering) is also used to identify and understand unknown technological objects in a similar manner to how Spellcraft is used to identify the properties of a magic item. The DC to correctly identify and understand an unknown technological object is equal to the object’s Craft DC. An object with a Craft DC of 15 or less can be automatically identified and understood by someone trained in Knowledge (engineering) who also has the Technologist feat.
And about Clockwork constructs they're identified as: Clockwork constructs are the technological cousins of golems, constructed with a combination of magic and precise technologies dependent upon the internal churning and turning of thousands of intricate springs, screws, and gears.
So it seems like not including Knowledge (Engineering) is more of an accidental omission than an deliberate one.
That's just something I've noticed. Though if there's been an Errata to correct that I haven't seen it.
Tinkerer alchemists have an affinity toward clockwork constructs; these fall under Knowledge (arcana), which tinkerers do get as a class skill. They aren't inclined toward robots for the simple reason that they weren't designed with higher technology in mind. If your particular tinkerer is interested in such things, though, that's pretty much exactly what traits such as Structural Knowledge are for. (It is annoying that most Knowledge (engineering)-boosting traits are religion or campaign traits, but hopefully there's something that meets your needs.)
Maybe not what you're looking for, but I think the mathematician trait gives you it as a class skill.