Mechanical inclinations have, for various reasons, traditionally been forte of men. The Wrench Wench is a girl who sets out to change all that. This can sometimes extend to pure electronic devices, but a Wrench Wench is more likely to be found with a blowtorch and ratchet set. She will always be confident about her own work, but because she's technically an enormous geek she sometimes has trouble with other things. She might also have Machine Empathy and can diagnose problems just by listening to the motor. She has been known to be Curious as a Monkey in the presence of new and interesting machines — or Constantly Curious, if inspection is impossible.
Usually too self confident to ever need a Beautiful All Along plot, but very likely to have at least one She Cleans Up Nicely moment even though she's often an Unkempt Beauty anyway. Tick her off and a Wrench Whack may be in the offing.
Can be used as a contrast to show that she's not as feminine as she first appears. She's often a Ms Fix It. Can also be The Blacksmith. When a Wrench Wench's talents go above and beyond the practical or realistic, she's also a Gadgeteer Genius. If it's computers and the Internet instead of mechanics, she's a Hackette. If her skills wax more technical than mechanical, chances are she's a Hot Scientist, though overlap can exist when dealing with things like mecha and androids which encompass both elements.
The Hood Ornament Hottie is a related trope, where the woman may be dressed or posed as if she was the mechanic, but actually is simply intended to be Eye-candy. A subtrope of The Engineer.
Ikuyo in Hanaukyō Maid Tai is the hand maid of the main character's Maid Corps and invents all sorts of inventions for the main character, which unfortunately have a tendency to explode or malfunction.
Miyuki Kobayakawa of You're Under Arrest! practically built her mini patrol car from the ground up, and maintains Natsumi's motorcycles.
Leyte in Tengen Toppa Gurren Lagann is the chief mechanic for team Dai-Gurren and is responsible for the majority of the upgrades to the mechs and the battleship.
Kana in Haibane Renmei is a tomboy who works in a clocktower and loves to work on machines.
Fio from Porco Rosso - who turns out to be the heiress of four generations of female aircraft builders. (Her great-grandmother wields a mean tinsmithing hammer.) The entire workforce of Piccolo Aviation are women, since the men are all abroad looking for work.
Rally Vincent in Gunsmith Catsis a gunsmith after all, and she's shown teaching May in the manga. She's never shown working on her own cars though, though she does wank over its capabilities at times.
Charlotte E. Yeager from Strike Witches. Before joining the witches she worked on motorcycles and airplanes, consequentially her striker unit is heavily modified. Even after joining the witches she spends her spare time in the machine shop and making further modifications to her striker unit.
Nae Aki in Medarot Spirits; she never was anything near fanservicey, but, in another hand, had Ikki slightly fawning over her. Justified by the fact that she's the granddaughter of Dr. Aki, the modern Medarot inventor. Thing is, if you considers the series' existence at all.
Hilde Schbeiker from Gundam Wing, who has her own scrapyard and is quite proficient with computers.
Bulma from Dragon Ball is this. She's handy with gadgets, and, along with her father, is usually responsible for creating spaceships, as well as Trunks' time machine.
Rikako Ota from Wangan Midnight, the daughter of RGO shop owner Kazuo Ota. She could dismantle and rebuilt a whole engine by herself down to the crankshaft, and is in fact slated to inherit her father's shop..
Miki Jounouchi from Future GPX Cyber Formula is a tomboy and chief mechanic for her racing team. She once takes out the damaged turbine engine from Super Asurada AKF-11 while it is still hot and injures her hands for doing that.
Chinatsu from Jormungand is a villainous example. When she's not gunning people down as part of her hitman duties, she apparently likes to build complex mechanical torture devices... including one designed to shoot a bound captive in the knee. In the same spot. 27 times.
Nanvel Candlestick from Burn Up W/Excess. Quirky but genius inventor and still as busty as most of her squad.
Hozuki from Galilei Donna actually carries wrenches around with her. And uses them to build some pretty crazy stuff, most notably an airship shaped like a goldfish.
The Ooarai Girls High School Automotive Club in the anime Girls und Panzer is made up of four highly skilled teen girl mechanics who not only work on cars but also maintain the school's motley collection of WWII tanks. In the later episodes they get to crew the notoriously cantankerous Porsche Tiger tank, doing as well as warriors as they did as wrench wenches.
Jane Buxton, in Secret of Cerulean Sand, attempts to follow her brother's tracks by building several flying machines and succed in the end.
Betty Cooper, from Archie Comics, is absurdly talented with auto repair and other forms of masculine expertise. This makes her either more or less attractive to the boys, depending on the story.
"Ma" Hunkel, the original Red Tornado from the Golden Age of The DCU, worked as a riveter during WWII. All that heavy labor probably helped with her right hook.
Maggie Chascarrillo, a.k.a. Maggie the Mechanic, from Jaime Hernandez's half of Love And Rockets.
Chassis was more of driver, but she certainly knew her way around the underside of a bonnet.
Courtney "Cover Girl" Krieger from G.I. Joe was a former high-fashion model who enlisted and became a missile-tank driver. Who does the upkeep and repair work on her own tank.
The ElfQuest title "Rebels" has Chandra. One example: she and Scorch take apart part of a top-secret space engine -and put it back together within twenty minutes.note A military ramship is excellent motivation
Olga Romanoff, an Air Policewoman in Ankh-Morpork, is also a largely self-taught broomstick technomancer who stands apart from other witches in that she knows what makes one go and is prepared to roll up her sleeves and really work on souping up the standard model. She and her friend and fellow flight technomancer Irena Politek operate a hangar full of customised broomsticks in City Watch service. working with Dwarf brothers the Messers Schmidt and Zlobenian dwarf Mig Oyeff, they currently fly ME-109's and the MIG-21 broomsticks. The prototype ME Schmidt 262 is going to be revolutionary. The girls appear in Slipping Between Worlds and other tales in the Discworld'' Expanded Universe.
Sky Bolt from The Dusk Guard Saga works as an engineer for an airship company. She is a compassionate tinkerer, working on improving deep water pumping in her spare time, among dozens of other projects. Her latest design, The Alicorn, had to be reverse-engineered, because nobody understood how it worked exactly, and so she would have been the only one able to maintain it.
Films — Animated
As bizarre as it may sound, Disney seems to be taking Tinker Bell, of all characters, in this direction with her CGI movie. The reasoning is actually fairly logical—why else would she be named Tinker Bell? Plus, the novel Peter Pan is based on states that Tinker Bell is a tinker who mends the pots and pans. It's not like Disney pulled this out of nowhere.
Jimmy Neutron Boy Genius: Jimmy Neutron's mother is seen working under the family car at one point. She also pointed out a flaw in one of Jimmy's inventions and explains it in full Techno Babble. It turns out she was very right.
Audrey from Atlantis: The Lost Empire is chief mechanic of a huge submarine despite being a teenager, and loves Machinery in general.
Films — Live-Action
Mikaela (Megan Fox) in the live-action Transformers is extremely good with cars but hides it from her boyfriend and friends to remain popular.
Mikaela: Guys don't like it when you know more about cars than they do.
Not that she ever gets dirty, or even works on cars all that much. It seems this was mostly an excuse for Bay to have her bend over a lot for the camera.
Kay and Hazel, the female leads in Swing Shift, both become wrench wenches after joining a munitions facility during World War II.
Mary in The Muppets is very good at working with cars and electricity.
The main character of C. E. Murphy's Urban Shaman trilogy is one of these, being a dedicated car enthusiast who restored a 1969 Mustang all by herself, and worked as a mechanic for the Seattle Police Dept. She even continues to use the idea of fixing a car to work her healing magics (fixing a broken windshield, replacing a flat tire, using windshield wipers to clear her vision, etc.).
Nadia Chernyshevski of the Red Mars Trilogy was a nuclear engineer in Siberia before her job building mankind's first base on Mars. Her skills in solving technological problems earned her the nickname "Universal Solvent".
Mercy Thompson, a.k.a. Mercedes the Volkswagen mechanic. She got started at 16 when she was sent to do community service fixing up cars, and now she owns and runs her own garage.
Samella Connel from Douglas Hill's Col Sec Trilogy, although her particular talent seems to be mostly with computer hardware and programming.
Linda Connor, from Swedish SF author Anders Blixt's dieselpunk spy adventure Iskriget (The Ice War), is a trained mechanic with a solid professional reputation in her home town. She "saves the day" with her skills at several occasions during the story. She usually wears workmen's clothes and has a male haircut, both for purely practical reasons.
Although Alice has spent most of her life studying sorcery her real gift is with watches and mechanical things, including her creating TheWitch Watch.
As both she and her father are highly ranked engineers, Laeshana from Quest Of The Unaligned has traces of this.
Second Lieutenant Cynthia Robbins of The Flight Engineer trilogy. In addition to being second-in-command of Invincible's fighter maintenance crew she developed an advanced prosthetic hand for her boss, Commander Peter Raeder, that led to him being able to fly again.
Leo's mom, Esperanza Valdez, was a mechanic and fell in love with the god of forges, Hephaestus. She received a college degree in mechanical engineering but never received a job in that field because because she was never taken seriously as a mechanic since she was a woman.
Nyssa was a daughter of Hephaestus. She was leader of the cabin of Hephaestus' children. As a child of this god, she could manipulate machines, as well as being an expert mechanic and builder. She could also sense machines, mechanic or metal and identify machinery types by a touch.
This is Lizzie's character in Spider Circus, technically she's called a 'wiredancer.'
Fae is the head mechanic in The Osmerian Conflict, and is almost always found in either the hanger or the electronics room doing some form of maintenance or mechanical checks.
Kaylee of Firefly and Serenity, as quoted above. Kaylee actually joined the crew because the captain walked in on her having sex with the ship's mechanic in the engine room. She diagnosed the engine's problem while in the act, and fixed it on the spot when Mal showed up. He fired his mechanic and hired her as she was getting dressed.
There are numerous hints (including dialog by the first ship's mechanic) that her major motivation in having sex with him there was to get up close and personal with the ship's engine room and grok it, she being a technophilic homebody / ground-pounder up to that point.
Bester: Engines make her hot, you know?
(Later, after Kaylee fixes the engine in two seconds flat:)
Bester: What'd you do?
Mal: She fixed it! Where'd you learn to do that, miss?
Kaylee: Just do it, is all. My daddy says I got natural talent.
In "Shindig" when Mal and Kaylee go to a ball she cleans up and gets to wear a fancy dress. She becomes an instant hit at the party when many of the men present find out that she works on engines and knows almost anything there is to know about them. Despite the fancy clothes it is still a frontier world and a technical whiz like her is highly respected, and the other female partygoers look to be socialites with little to offer but small talk.
Turns into a CMOF when a young man asks her to dance and everyone else tells him to leave her alone, she's talking about engines!
Gilina Renaez from Farscape is a technical specialist for the private army she works for.
B'Elanna Torres from Star Trek: Voyager. Although Star Trek engine rooms tend to be cleaner than a modern-day operating theatre, she does still manage to get covered in dirt and grease on a fairly regular basis.
Theora Jones of Max Headroom is of the high-tech variety rather than the grease-monkey variety.
Ashley Hammond in the Power Rangers Turbo episode "The Turn of the Wretched Wrench". Conversely, this was the day job of her Japanese counterpart, Natsumi Shinohara from Gekisou Sentai Carranger: she's good enough to dismount a moving bike.
One scene showed her working closely with a mechanical object very intently, as with her it's likely an alien device of some kind. The camera pulls back to reveal tuning up her bike.
Sanctuary has Dr. Helen Magnus, also played by Amanda Tapping, who again falls under this trope. Very obvious in episode 21, where they get stuck in an old oil rig and need to MacGyver their way out.
While we didn't get to see much of it "on panel," DG from Tin Man seemed happiest either drawing or fixing stuff with her robotic foster dad.
In one episode of Home Improvement, car enthusiast Tim gets a new mechanic who is one of these, which leads to him becoming slightly attracted to her. Of course, the fact that she's played by pre-crazy Jenny McCarthy doesn't hurt, either.
In Degrassi Goes Hollywood fashion model Mia, who tags along on the journey to L.A., later ends up helping fix the broken down bus with her expensive leggings, saying it was an old trick her mom taught her.
The Audiobooks for The Sarah Jane Adventures make this into Sky's way to assist the team, in a much cuter and less fanservicey way. Her ability to sense and understand energy being part of it, but she just understands machinery.
When the family starts fixing up a car for Matt in season 3 of 7th Heaven, it's boy-crazy Lucy who is shown to be an idiot savant when it comes to cars.
The Cold Case episode "Factory Girls" featured a troop of these building planes to be used in World War 2.
All the girls on Mythbusters. The most famous, Kari Byron, is actually a lighter example than the other two, being an artist by training. Scottie Chapman from the earlier seasons is a much straighter example, being a welder and metal worker. Jessi Combs, who filled in for Kari when she was on maternity leave, is a metal fabricator.
Given her heritage, Marti in Slingers would be expected to be technically skilled, and so far she's demonstrated a definite affinity with spaceship power systems (and the disabling thereof).
In The Protomen (a rock opera based on the Mega Man (Classic) series), Dr. Light's lover works in a factory. Keeping her safe from a dangerous job is part of his motivation for creating the robots central to the series. Of course, Dr. Wily has other plans.
The entire first verse from Felt's "Dirty Girl" is about this. Lines include "Standin' there holding that drippin' dipstick/With a firm grip, yet so delicate/And the way you took that orange oil rag and wiped it clean/Its guaranteed to get repeated in my dreams" and "Got so lost in your smile when you asked me what the mileage was"
The Beach Boys' "Car Crazy Cutie" is an ode to a woman who shares her beau's enthusiasm for automobiles:
Well, my steady little doll is a real live beauty
And everybody knows she's a car-crazy cutie
She's hip to everything, man, from customs to rails
And axle grease embedded 'neath her fingernails!
The music video for Girls Aloud's "Long Hot Summer" is set in a mechanic's shop with the girls sporting boiler suits and working on cars.
Led Campbell from Septerra Core is a genius mechanic, her weapon is literally an enormous wrench, and she's so hot that total strangers will give her money or items..
Tali'Zorah from Mass Effect who's part of an alien race called the quarians. Quarians are the whole race of incredibly skilled engineers. And even among the quarians, she is counted one of the best engineers and geth specialists.
Like most character tropes involving the squad, Fem Shep can qualify for this one too - just make her an engineer.
They are joined by Samantha Traynor in Mass Effect 3, though she's more the communications officer and spends her time cracking code.
Moira Brown from Fallout 3. You, yourself, qualify as well if you're the female version of the Lone Wanderer and spend up on Repair skill points.
Veronica has a bit of this going on as well. She can even function as a mobile Workbench that lets you craft items on the spot.
Licca Kusunoki in Gods Eater Burst fits this to a tee, in charge of maintaining the Far East Branch's God Arcs. complete with oversized gloves and a tendency to hug the protagonist when they do something stupid.
Wave the Swallow in Sonic Riders, who is the one responsible for building the boards for the Babylon Rogues.
When Starkiller first lays eyes on Juno Eclipse in Star Wars: The Force Unleashed, she is working on his ship, The Rogue Shadow. The comics also show her working on other equipment.
Robin from The Iconoclasts is a mechanic in a world where mechanical engineering is illegal.
Touhou Project gives us Rika in it's 2nd installment, who builds tanks, and is rarely seen without her wrench in fanart.
Kawashiro Nitori from Touhou 10 Mountain of Faith, like most kappa in the series, is a Magitek engineer who dons optical camouflage, extendible robots arms, and missiles. She's really fond of human technology that falls across the Great Hakurei Border and, according to common fanart, has her own lines of electronics.
When Sunny Gurlukovich/nee Emmerich first appeared in Metal Gear Solid 4 she was a shy computer hacking expert with a No Social Skills and a slight stutter, but by the time Metal Gear Rising: Revengeance rolls around, she's become a capable and confident engineer who helped develop the fastest suborbital thruster the world has ever seennote Capable of reaching speeds in excess of Mach 23 and is actively working on a spacecraft able to make the journey to Jupiter within her guardian's lifetime.
Borderlands 2 gives us an unusual example, Ellie. Although she is one of the most obese characters in the game, speaking to other characters and listening to audiologs reveals that there are some poeple on Pandora who like it that way.
Pella the dwarf, from Looking for Group. She fashions Rayd a replacement arm after the Black Dwarves dismember him while torturing. Rayd then uses it to "keep a promise" that he made them in a subsequent battle with the Black Dwarves.
Faye from Questionable Content recently entered these waters when she built a mini T-Rex that poops espresso, and was originally going for a two-ton T-rex with Hemi power.
Dora, too, has managed to do similar, but from a more computer nerd end of the spectrum, like fixing Pintsize back together after an unfortunate cake mix incident.
Marigold builds her PCs, has taken over the Pintsize fixing, is a webmaster as her real job, and seems to be rather skilled at all things computer.
Shelly from Wapsi Square worked at a garage earlier in the strip's run.
Agatha Heterodyne, from Girl Genius is a perfect example of this trope, and she has only become more so as the series has progressed. Before she discovered she was a Spark, she used to sleepwalk and construct massive mechanical devices while clad only in her underwear.
Jade Harley from Homestuck qualifies as she built a freakin robot copy of herself that allows her to do stuff while asleep, useful for a narcoleptic
Sasha in Sluggy Freelance is able to understand and often improve on Riff's inventions.
Katherine Blanco from Survival of the Fittest version three was the best mechanic in her school until she was killed by a hornet's sting on the island.
Sharon from Darwin's Soldiers used to work in the magnetic materials research division at Pelvanida. After she got fired, she worked as an electrician and a mechanic in Southport.
Tex, actually, of Red vs. Blue. She's repaired Sheila at least twice, built a bomb out of spare parts (including some more ... personal items), and even upgraded her own armor while wearing it. Apparently, this was part of her Freelancer training. It tends to be overshadowed by her repeatedly kicking everyones' asses, though.
There are quite a few female gadgeteers, devisers and general scientists in the Whateley Universe, but special mention goes to Loophole, whose power is 'understanding rules'. Any and all rules.
Gaia Online brings us Sam, the young lady who runs the automotive shop "Sam's Body and Parts".
Gretchen Grundler and Ashley Spinelli in Recess. Spinelli was taught by her older brother how to work on cars and helped fix a broken down bus in one episode. "Regular, or ratchet?"
Sari from Transformers Animated, in a way. Pre-upgrade, she's the Allspark's deputized Angel of Phlebotinum, then post-upgrade she shows a real talent for Cyber-diagnostics.
The second season of Transformers Prime involved finding ancient Cybertronian weapons created by Solus Prime, one of the 13 original Primes created by Primus, who was also the archetype for female Transformers to come. She preferred a big hammer over any old wrench.
Molly from Ōban Star-Racers is a competent mechanic. She even figured out the problem with a pod-racer when it had previously stumped a professional.
Cover Girl from G.I. Joe (especially in her Devil's Due comic incarnation). After all, when your primary duty is as a missile tank driver, it pays to know how to keep your fighting vehicle in good condition.
Star Wars: The Clone Wars: Ahsoka has apparently taken a level of this over the course of the series' sporadic timeline; by the time of the Mortistrilogy of episodes, she's capable of fixing a badly crashed shuttle by herself and modifying it as needed.
Gadget Hackwrench, proving that when it comes to ingenuity and mechanical marvels, size doesn't matter.
Scootaloo is shown doing mechanical work on a parade float in the My Little Pony: Friendship Is Magic episode "One Bad Apple." Later, in "Twilight Time," she's shown developing these skills further under Twilight Sparkle learning how to disassemble and reassemble unicycles and scooters.
Luanne in King of the Hill was bad in beauty school and the community college, but she was good with a wrench. In early episodes, the men in the alley would move out of the way and let her fix cars.
Rosie the Riveter from the U.S. World War II propaganda. And, obviously, all the female mechanics used in propaganda.
Elizabeth Hawes' book about working in an aircraft plant during WWII is titled Why Women Cry; or Wenches With Wrenches.
Mike Holmes has made a point of supporting women going into construction trades on his shows Holmes On Homes and its sequels. He hired Corin "Pinky" Ames on air after she completed an internship with him, and Kate Campbell and Mike's daughter Sherry are regular members of his crew.
There are self-help bike repair shops in Germany (and possibly other places in Europe) where you have to repair your bike by yourself and only pay for the materials used. They are run by volunteers who help you if you're stuck, and many of these volunteers are girls who do this in their free time.
Ada Lovelace, the first computer programmer. In the first half of the 19th century (she was Lord Byron's daughter). That's right: even before the first computer - she invented algorithms for Charles Babbage's Analytical Engine, which is considered the "ancestor" of modern computers.
Note that her mother directed her education towards maths (and music) since she thought the "poetic tendencies" from a typical woman's education of the day were "dangerous" (which is to say she thought poets were trouble; having married Lord Byron, she was probably right)—a course of action with which Lord Byron totally agreed, since young Ada was excellent at maths. Lovelace was nevertheless as feminine as the age required, marrying a count and giving him three children.
Pornstar Phoenix Marie is a lovely and feminine woman ...who rebuilds classic cars, rides and maintains Harleys and plays soccer and baseball in her spare time.