Wrench

MeleeToolTiers I–IV

Spawns a turret that shoots bullets dealing 10 (+80% Engineering) damage
Spawns a turret that shoots flames dealing 8x5 (+33% Engineering) burning damage
Spawns a turret that shoots piercing bullets dealing 20 (+125% Engineering) damage
Spawns a turret that shoots explosive bullets dealing 25 (+150% Engineering) damage in an area

Unlock: Available from the start
Starting weapon for: 24 characters

Community builds that use it

ApprenticeLevel-ups give every damage stat, so hybrid weapons pay off: Plank, Lightning Shiv and Cacti Club, or SMG/Double Barrel Shotgun and Slingshot for ranged. Take Luck to reach the higher Max HP level-ups.
ArtificerExplosion build: start Shredder and move to Rocket, Grenade or Nuclear Launchers, or use Planks; stack Explosion Size and Elemental Damage, which also enlarges explosions. Wrench and Screwdriver became viable after Tool weapons got +100% damage in 1.1.0.0.
BabyNo level-up stats, so all stats come from the shop; Sticks are the standard choice because base damage grows with each Stick held, and survivability needs Armor, Dodge and Max HP. XP Gain items and a broad mixed melee loadout are alternatives.
CyborgKeep the Minigun, add guns that scale with Ranged Damage and Engineering weapons (Wrench or Plank), and put upgrades into Ranged Damage rather than Engineering, since Ranged Damage converts to Engineering mid-wave.
DroidEngineering turret build on Wrench and Screwdriver with Mecha evolution; stacks Engineering, Dodge and Armor.
EngineerSix Wrenches (or Screwdrivers) and every turret item, putting level-ups into Engineering, Armor and HP Regeneration rather than weapon damage.
EntrepreneurThe -50% Damage modifier pushes most guides to an Engineering build with Wrench turrets, which ignore it; Support weapons such as Sickle and Pruner exploit the boosted Harvesting. Spend all materials every shop because they are lost at the start of the next wave.
ExplorerEngineering avoids the -40% Damage penalty, with Pocket Factory the key item; Cacti Club spines also cut down the extra trees. Shredder explosion builds and Sticks are other recommended starts.
Mad ScientistTurret build on Wrench and Screwdriver that also uses Evolution items; stacks Engineering, Dodge and Attack Speed.
MultitaskerTwelve Sticks is the standard build because each Stick raises the others' base damage; get % Damage back to positive after filling the slots. Guns, elemental weapons with Snake and Scared Sausage, and 12-turret Engineering builds are reported alternatives.
OldThe small map favours Engineering: Wrench turrets and Landmines stay on screen, so stack Engineering and defensive stats. Double Barrel Shotguns are the gun alternative because enemies bunch up; guides also report Taser/Wand elemental builds.
StreamerStand still with a ranged weapon (SMG early, Revolver late, or Slingshot) and invest in Ranged Damage, or run an Engineering Wrench build that never levels damage stats; every structure item adds Armor. Do not start waves holding very large material piles.
TechnomageEngineering with Wrench turrets is the reported easier route after the XP nerf, while elemental builds use Taser or Plank and buy every structure. Strange Book converts Elemental Damage to Engineering.

Stats by tier

Tier I Common
Damage
12 (+100% Melee Damage)
Cooldown
1.7s
Crit
x2 (3% chance)
Range
175
Tier II Uncommon
Damage
16 (+100% Melee Damage)
Cooldown
1.64s
Crit
x2 (3% chance)
Range
175
Tier III Rare
Damage
20 (+100% Melee Damage)
Cooldown
1.55s
Crit
x2 (3% chance)
Range
175
Tier IV Legendary
Damage
24 (+100% Melee Damage)
Cooldown
1.49s
Crit
x2 (3% chance)
Range
175

Damage in brackets is added from your stats before %Damage multiplies the total; see the damage formula or the calculator.

DPS at tier IV

16.6 DPS with no stats, 30.4 at 20 Melee Damage and 51.2 at 50 (single target, every projectile hits, crits averaged): #54 of 58 weapons that scale with Melee Damage. Full ranking or your own stats.