Any gambler who’s watched a vintage movie about Las Vegas has probably seen a traditional mechanical slot machine. While most games are now based on a random number generator to guarantee a completely random outcome when playing, traditional slot machines used actual moving parts and mechanics to accomplish this for many years.
Since their invention in the late-19th Century, slot machines have undergone numerous changes and technological advances. However, for decades players won and lost slot tokens and cashed in for jackpots based on the actual mechanics within these popular games.
Keep reading to find out a bit on how these mechanical slot machines worked and if they can be found for playing today.
How Do Mechanical Slot Machines Work?
Most slot players take the act of popping a few dollars in a slot machine or opening up their mobile phone or laptop to spin some reels for granted. It's pretty easy to get in on the action and modern games feature plenty of “bells and whistles” – from high-definition video with mind-blowing graphics to cinema-style sound effects to easily-changeable betting options.
But these types of options weren’t always the case. Early machines featured single denominations of stakes and very few bells and whistles (although bells were a common symbol on early machines). Despite these limited options, early slots were highly popular with gamblers. Machines are the main draw and gambling revenue drivers for most casinos around the world.
“There has never been any other gambling device which has produced such enormous profits with so little effort on the part of the operator,” Scarne’s New Complete Guide to Gambling notes. The author adds: “The slot machine is the only mechanical device with a mechanical banker that collects losing bets, pays off winning bets, and makes fewer mistakes than any human dealer in any casino banking game.”
Early machines were manufactured in machine shops and made use of mechanical gadgets instead of techno-wizardry, although there definitely was some skilled engineering to make these gambling devices work. Many of these classic games made use of typical machine-style components including:
a cabinet (often metal in early days) to encase the mechanics
gears
levers
metal shaft to support the spinning reels
notched discs
kicker
connected stoppers
Classic machines may vary a bit, but this is the general idea on how the mechanical inner workings of a slot machine work. A metal shaft is a key part of the machine’s functions by supporting the reels (usually only three on older machines), which display various symbols and signify a certain action such as a win, loss, or jackpot.
The shaft is connected to a handle protruding from the machine (hence the nickname “one-armed bandit”). Some modern machines feature a handle as well, although they really only activate the slot’s computer software. But in these older machines, the handle actually worked to get the mechanical reels spinning and in motion.
A braking system brings the spinning reels to a stop to signal a win or loss. Later machines also made use of sensors to enable payouts based on the position of the reels. More advanced mechanical reels eventually also used coin detectors to initiate the game after a coin was inserted into a “slot” – giving the games the name “slot machines.” This mechanism released a brake so a player could move the handle and go for a spin.
What is the Kicker and Stoppers?
There’s a bit more to this mechanical process with devices called “kickers” and “stoppers” playing a major role. The three reels on the central shaft also house three notched discs. A second shaft supports the slot kicker.
This piece is made up of three paddles that intersect with and push against the disc notches. This second shaft also supports several connected stoppers, which protrude into the disc notches. The kicker and stoppers are joined to springs, which lock them in a “standby” position.
When the handle is pulled, these are released until they come to a stop and the reels display that spin’s results. Line them up just right and some slot token or cash are headed your way. The actual specific mechanics of the machine varied by manufacturer, but as noted, this is the general idea of how mechanical slots work overall.
It seems as the world became more industrialized and new manufacturing processes gained favor, creating a machine that mixed entertainment and gambling just seemed inevitable. Who knew how immensely popular these games would actually become?
“With the emphasis on streamlined production and mechanization that came with the Second Industrial Revolution in the late 19th Century, it was only a matter of time before someone invented a machine that could help people gamble faster and more efficiently,” author David Schwartz notes in Roll the Bones: The History of Gambling.
Which Pays Better, Video or Mechanical Slot Machines?
Part of the fun of playing a slot is the hope that a nice win is heading your way. But cash payouts weren’t always the case. Charles Fey invented the first coin-paying slots in San Francisco in 1895. Earlier machines were more mere amusement devices and paid out prizes such as:
cigars
chewing gum
candy
more free spins on the machine
free drinks
But Fey’s machine revolutionized the gaming industry, transforming this amusement device into a gambling slot machine. His first machine, known as the Liberty Bell, paid out 50 cents when three bells lined up across the three reels.
Slots can now be found in casinos throughout the globe as well as online on real-money gaming platforms and in social media mobile gaming options. Gaming options have changed dramatically but the general idea that payouts come via finding fortuitous luck on those spinning reels remains.
Obviously, as advances were made, payouts advanced beyond that initial 50-cent win on a Liberty Bell. Players could wager higher denominations and also win on multiple lines.
Modern video slots offer much easier ways to win at much higher denominations. However, players must also be willing to wager more per spin because of so many paylines now available to players.
Modern slots also offer the chance to win progressive jackpots as well, which can reach staggering sums. These are reached by games being linked across numerous locations and jurisdictions. A small portion of each spin is put into the progressive payout pool and players getting extremely lucky can take all or even a smaller share of that total.
In general, players now have many more opportunities to win on a video slot machine or a game with spinning reels but also using modern software and technological engineering.
How Do Mechanical Slots Produce Random Results?
The mechanics of a mechanical slot help produce random spins based on the actual spinning of the reels. The kicker and stoppers eventually help bring them to a stop as the reels begin to slow. Is this truly random?
That depends on one’s perspective. But in the age of computer software, probably not a perfectly random outcome. The mechanics of these games may have favored certain results occasionally but manufacturers were working with real machine parts and worked to make these results as random as possible. Gaming commissions also worked to make sure these were fair games.
This is much different than modern slots. These games make use of a random number generator (RNG) to predetermine an outcome before a player even spins the reels. The software predetermines the outcome based on algorithms for a completely random result. Modern slots are much more computer and software than an actual machine.
What Happened to Mechanical Slot Machines?
As computers became more in use in the 1980 to 2000s, slot began to transform. Slowly those mechanical inner workings were replaced by more modern technology. Developers could create more entertaining and innovative games using new technology.
Even the use of coins and slot tokens faded away. Players could use cash and then be paid out in vouchers which could easily be used in other machines. All these changes revolutionized the industry and this saw a surge in the games’ popularity. Players loved numerous new features such as:
user interactivity
video clips
multiple paylines
bonus rounds
free spins
pop culture tie-ins such as movies, TV shows, and musical acts
Many slot machines began featuring a narrative element or at least a common theme, such as ancient mythology, animals, or almost anything else imaginable that might resonate with players.
This new breed of slot machines began replacing those older machines featuring real mechanical reels and inner workings. Many were scrapped but some vintage games remain sought after by collectors. Perhaps you’ve seen one in a friend’s game room or in a museum such as the Mob Museum in Las Vegas.
A few Las Vegas casinos still offer the chance to gamble on some vintage machines. Some may feature a bit of computer technology but offer the best chance to gamble on classic mechanical slots. For those looking to play some slots of a bygone era, the best place to find some is probably in downtown Vegas. Grab a bucket of quarters, drop a few in the “slot,” pull the handle, and hopefully a nice win is heading your way.
Frequently Asked Questions
How do mechanical slot machines work?
These older machines make use of gears, levers, discs, and other mechanical inner workings to determine the results of a spin of the reels. Early machines featured only machine inner workings whereas today machines make use of software and technology to determine wins and losses.
Can players win more on a mechanical slot or modern video slot?
Modern machines offer numerous ways to pay, high denominations to wager (and win), and the opportunity to win progressive jackpots.
Did mechanical slots feature random results?
The outcomes of a slot were as random as possible based on the technology at the time. The reels spun after pulling the handle and eventually stopped due to the mechanics found inside the slot cabinet.
