GENERAL INFO

Tinkering is a Gnome racial ability that starts off at the skill level of 50, and can be raised once the player level reaches 16 or higher.  Currently the skill improvement rate is similar to the research skill(?), which means a formula of:   5 x (level - 15). So the maximum skill that one can obtain is:
...

LEVEL-----SKILL
32----------85
33----------90
34----------95
35----------100
36----------105
37----------110
38----------115
39----------120
etc.

Other races besides Gnomes can tinker, but will never gain any skill, making it very difficult if not impossible to make the high difficulty items.

INFO FOR BEGINNERS

To begin learning the skill, visit Bom Knotwood at the windmills in the Steamfont Mtns. and Rylin Coil in Ak'Anon. These two merchants carry most of the tinkering parts you will need, including the tinkering books and the toolbox, which you will need to combine the parts in to make new items.

Below is a general outline of the items and trivial level, ranked from smallest to highest. Note: some of these numbers are estimates!
 

• Animated fishing bait - 50 -- Effect: fishing bait
• Firewater - 50 -- Effect: tinkering component
• Fireworks - 50 -- Effect: Fireworks(1-4) 1 charge each, light display
• Compass - 50 -- Effect: Sense Heading skill (right click for item description)
• Thermal Cloak - 50 -- Effect: +?AC, +SV COLD cloak
• Collapsible fishing pole - 53 -- Effect: 0.3wt, fits in all containers fishing pole
• Mechanized lockpicks - 68 -- Effect: better lockpicks for Rogues (+?? skill?)
• Flameless lantern - 68 -- Effect: greater lightstone power lantern, must be used in 2nd melee slot
• Standard bow cam - 75 -- Effect: bow cam for fletching skill, can make these cheaper than buying them from a merchant with a good skill (80+)
• Spyglass - 95 -- Effect: Glimpse spell, unlimited charges
• Stalking Probes - 102 -- Effect: Stalking Probes, 5 charges Eye of Zomm spell
• Gemcutter - 120 -- Effect: Item for jewelcrafting skill?
• Aqualung - 148 -- Effect: 50 charges of Breath of the Dead spell
• Rebreather - ??? -- Effect: Unlimited underwater breathing, wear on head slot

ITEM PLANS

The formulas for the items:

• Animated bait - 1 cork, 1 spricket
• Firewater - 1 water flask, 1 Gnomish spirits (drink bought at bars)
• Fireworks - 1 metal shaft, 1 bat wing, 1 firewater
• Compass - 1 pie tin, 1 skewers, 1 water flask, 1 static orb, 1 cork (smiths and potters can make pie tins and skewers)
• Thermal Cloak - 1 Tattered Gnomish Cloak, 1 firewater, ? metal rods (small patchwork cloak = tattered Gnomish cloak? No formulas thus far have worked)
• Collapsible fishing pole - 3 metal rods, 1 Gnomish bolts
• Mechanized Lockpicks - 1 lockpicks, 1 gears, 1 sprockets, 1 rat ears (kill Steamfont rats for these)
• Flameless lantern - 1 large lantern, 1 metal twine, 1 firewater
• Standard bow cam - 1 gears, 1 grease, 1 Gnomish bolts
• Spyglass - 1 collapsible fishing pole, 1 bottle, 1 metal twine, 1 metal rod, 1 reflective shard
• Stalking Probes - 2 gears, 1 firewater, 1 metal rod, 1 bottle
• Gemcutter - 1 metal rod, 1 diamond dust, 1 standard bow cam, 1 metal fastening, 1 firewater, 1 grease
• Aqualung - 1 fine coral mesh, 1 Silk Lined Steel Helm, 1 metal twine, 1 Gnomish bolts, 1 metal rod, 1 fresh fish
• Rebreather - 1 aqualung, 1 lime coated meshing, 1 sharkskin tubing, 1 medium size platemail helm, 1 firewater, 1 metal fastening

Credits go out to all the gnomes who have spent countless platinum pieces figuring out this skill since EQ was released.