i was wondering a couple things. What would you have a steam-powered melee weapon be when it's not working? I always ran with the idea of a chattersword being simply a greatsword when it's not on, and a buzzaxe being like a greataxe, but what about buzzsaws?
You could probably treat buzzsaws as some sort of axe, depending on the size... that's probably the closest equivalent to the toothed blade.
also, would it be a stretch to say that masterwork steam-powered weapons (including steam rifles and such) would run off clockwork engines, going with the whole 'masterwork is of a greater quality than standard' idea? i guess it would be only thematic, with the exception of rarely (if ever) needing water anymore and them not being as loud, but... what do you think?
I think that's a great thematic idea.
Also, would a masterwork steam engine (Either a coglayers or a steamborg's) be clockwork as well, how much would it cost to make it so, and would it have any added bonuses? I'd say a clockwork steam engine for a steamborg would negate the hide penalties, but what for coglayers? +1 on rolls using steam powers attached to said engine?
If you take tables 2-13 and 2-16 from DragonMech and work out the typical cost ratio by size, a clockwork mech's labor cost and materials cost averages 2.6x that of a steam powered mech. So you could easily use 2.6x as the multiplier. The standard d20 "masterwork item" rule is +300 gp, so maybe use +300 gp or 2.6x the cost, whichever is more. I agree about negating hide penalties. For coglayers I wouldn't go so far as to give bonuses to rolls, but I'd treat it more like masterwork armor, which simply reduces penalties. Of course, there aren't a lot of penalties (such as armor checks) with steam powers, but maybe each item built onto a clockwork powered engine could have a size value of 1 lower, to reflect the lighter weight due to lack of water pumps, hoses, etc. (By "1 lower," I mean it goes from "Tiny (6)" to "Tiny (5)", not a full increment lower.)
Also, would a clockwork engine even really need water anymore? I know mech clockwork engines need the water and fuel just to recharge, but what about a hand-held clockwork engine?
For a handheld clockwork engine, you could just require a Strength check to rewind it -- maybe once a day it has to be rewound with a DC 20 Str check, or something along those lines.