So I was looking at the craft rules and it seems like you pretty much need a metric but-load of advantage in order to build anything with more than a slight upgrade on the base item stats. Or maybe I'm missing something. So I was wondering if there was a way to convert success to advantage to be able to build a truly tricked out custom item?

I looked at custom tools and I can get one free success and advantage if I create those first and a schematic can reduce the difficulty one. Are there any oyher tools that an help? Inventor will give a boost per rank and brace can remove a setback for the environment but are there any other talents that can help? Any other options to help I may have missed?

there's a talent in some of the special modifications specializations that lets you swap success for advantage (Eye for Detail I believe is what it's called).

The crafted Gadget "Specialist tools" with the "Safety Feature" effect, thats already been mentioned.

The "Eye for Detail" talent already mentioned.

The "Inventor" talent already mentioned.

The " Journeyman Tools Inc. Custom Tool Kit" that add a boost die.

A Shipboard Workshop adds an automatic Advantage.

Getting the "Schematic" effect enough times to bring the checks down to Simple for the template you want to craft.

Other than that i think it's pretty much just the "Practice Makes Perfect" and "Lessons Learned" effects from crafting

Things that you can do that I have found :

Force Power Tree : Manipulate (Endless Vigil) has a Control power which lets you turn force points into advantage, and a Mastery that turns two force points into advantage, as part of a Mechanics check.

Sentinel : Artisan has Master Artisan to reduce difficulty and Natural Tinkerer to reroll Mechanics once per session (as well as the over the top good Intuitive Improvements - though you'd cheesily use that when repairing so you can spent the force points on Manipulate).

Inventor - As you say, I think there are 7 ranks available.

Eye for Detail - As Klort says there are 3 (2 in Droid Tech, 1 in Cyber Tech)

Smuggler Gambler tree has Double of Nothing, which can double the number of advantages (and triumphs with Supreme), and has Second Chances to allow some rerolls.

Technician Signature Ability: Unmatched calibration is handy for rerolling just particular dice.

Smuggler Signature Ability: Unmatched fortune is another great dice changer.

Most (all?) crafting lets you spend 1 advantage for one boost on the next Mechanics use that session, with Practice Makes Perfect, which is uncapped by RAW.

With great luck (with Manipulate Mastery, small luck) you can make a Specialist tool that adds Success, Advantage and upgrades the check.

GM could get you a workshop (Special Modifications), which can convey various bonuses.

You can get a Mechanics skill cyber implant (Special Modifications) to increase Mechanics, and a Brain implant to increase Intellect. A Cyber Tech can overcharge both with Supreme Overcharge.

Make sure you increase your Intellect and Mechanics too of course, and get some unskilled assistance for another Boost dice.

Of course, you'd need stupid levels of xp to manage all this, so just go with what seems fun. Whilst Gambler -> Force Sensitive X -> Artisan -> Cyber Tech -> (others) might be the best crafter path in the end, it won't be good for a long while.

Personally I have an Artisan / Cyber Tech, who hasn't yet got Supreme Overcharge or Intuitive Improvements or Natural Tinkerer or taken Manipulate powers. He does have a specialist tool that adds Success/Advantage, and Mechanics/Brain Cyberware. His best roll (on some Segmented Armour) was 10 advantages and 1 triumph (on the second set he made, first set he traded advantages to learn schematic, lessons learned to reduce next difficulty and I think 3 boost dice for next try from Practice Makes Perfect - note that you cannot overcharge AND use practice makes perfect, as it is also a Mechanics check)

Hmm, lack of cap on Practice makes Perfect and Double or Nothing is a dangerous combination, means every Boost die could give 1.33 boost die to a next roll !

There is a cap, it's called a GM that doesn't let Princess Snowflakes get away with power gamer mmo video game BS.

Oh, I agree, though I'd have preferred it had a cap in the rules, as it does for most crafting results.

Hmm, we have a home based and I want to put a workshop in there so I'll have to run that by the GM to see if I can install the "ship version". What book is that in?

I never would have considered that you could get the boost die more than once. I don't recall it mentioning that you could.

I was pretty sure you could only do schematic once. I recall it saying that.

I'll have to look for an eye for detail. Somehow I have the feeling it's not in any trees that I had been considering.

3 minutes ago, Darzil said:

I'd have preferred it had a cap in the rules, as it does for most crafting results.

That in itself is a very strong clue that it's supposed to have no limit. It's a deliberate design decision. You can argue over whether it was playtested enough, or whether 10+ boosts are abusing the system, but it's working as intended.

You can only do schematic once per crafting attempt. So you can gradually whittle them down to simple (-)

2 minutes ago, Ahrimon said:

Hmm, we have a home based and I want to put a workshop in there so I'll have to run that by the GM to see if I can install the "ship version". What book is that in?

SM:95.

7 minutes ago, Darzil said:

Oh, I agree, though I'd have preferred it had a cap in the rules, as it does for most crafting results.

You'll find more than one instance in the game rules where it's intentionally left broad and that's on purpose. It's too hard in some cases to hit the exact sweet spot for certain mechanics so they don't try and leave that to GM's, which is what GM's are for. All that is required in this instance is for a GM to feel there needs to be a cap, and there is. RAW aren't dogma.