good fucking GOD gears are annoying. I have 25 workshops and 30 smelters and it still takes hours to make enough to be useful(such as nabbing Printing Press, much less the 10 or so Steamworks to make use of it). It wouldn't be so bad if they didn't need 15 steel, which requires 100 iron and coal(the coal is the sticking point, as at this point of the game you can only get it from mines and burning wood, so it comes in pretty slowly)
Only for a very brief window. Gears benefit from the workshop conversion bonus
twice. 10 gears times 15 steel is 150 steel, times 100 works out to a base cost of 15,000 coal plus 15,000 iron for 10 gears. But with 25 workshops, your 2.5 multiplier is applied twice instead of just once. So instead of 15,000 / 2.5 = 6000 each of coal and iron, it's actually much less:
3600 / 100 = 36 conversions, times 2.5 = 90 steel. 95 steel / 15 = 6 conversions, * 2.5 = 15 gears.
You only need 3600 each coal and iron instead of 6000. And the more workshop you have, the more that double application works in your favor. So max your workshops, and gears become not such a big deal. Plus, I find that I don't need many gears. Steamworks production rates are very slow. Unless you're doing a lot of overnight afking, I don't see a lot of reason to build very many of them. Plus, some of the upgrades aren't as important as others. The coal consumption reduction is n't a big deal, for example, since if you're afking overnight, you're going to cap coal anyway and it doesn't really matter if you cap in 20 vs 30 minutes. And the plate production upgrade, while definitely useful, pales in comparison to the inevitable mass plate production you get later from the zebras you end up spamming every winter to get titanium. So it's not terribly important. Really, the manuscript production is the only upgrade I find very useful, and even that the production rates are so low that again, unless your'e doing a lot of overnight afking, it's probably not worth building many steamworks to take advantage of it.
Basically, don't sweat the steamworks too much.
Starcharts and scaffolds are both much worse.
what the hell should I do with all the excess steal those smelters produce?
Stockpile it. You'll need it in stupidly large quantities (much) later to convert titanium into alloy.
Though note that if this is your first playthrough, it's possible that you might end up resetting before you get to that point, so don't stress over it too much.
EDIT:
Wait, that was a typo. You meant iron, not steel, right?
Excess iron, use to make lumber mills, and convert anything extra beyond that into plates. Wood is a major bottleneck through every part of the game I've reached, and lumber mills are good to have. Plates will be used 150/each for ships, plus several hundred at a time for harbors. Those will be needed in largq quantities, and while yes you do end up having loads of iron dumped on you by the zebras (I had 14,000 iron dumped on me with a single click of "trade all" maybe 5 minutes ago, for example) it's nevertheless convenient to have a few thousand plates on hand already once you get to that point. Reason being, the zebra gives you iron and plates that you don't care about, but do anyway because it gives you titanium too. The titanium trade is increased by the number of ships you have, and you need plates to build ships. So once you have it going, it's self perpetuating (except for starcharts which are a pain) but having a few thousand plates ready and waiting when you get to that point will help you jumpstart the process.