For all you people powerleveling this profession for this glove enchant (or any other tinker), this is NOT a random discovery in it's current state after the bugfix. This is not like alchemy where you create a couple hundreds of potions that are grey and suddenly make a discovery.
Do not make the same mistake as I did...powerleveling Engineering and as soon as you hit 450 starting to crank out either Electrified Ether or Obsidian Bolts. While making the Ethers I discovered 3 tinkers, but got no more skillups after 365. Coincidentally I also did not discover any more tinkers after making about 30 Ethers while it was grey. After that I started with Obsidian Bolts, did about 100 grey crafts but did not discover any tinkers. Cursing Blizzard for bringing this RNG, I continued leveling Engineering. My next craft was one with 5 skillups and immediately discovered a tinker. I did 2 more 5 skillup crafts and there it was..the Synapse Springs tinker.
TL;DR - if you do not get this enchant at 450, continue to skillup Engineering. Do not make low material grey crafts hoping you discover this tinker.