How to open locks
So you bought a non-working pinball machine somewhere, or stumbled upon a warehouse find with dozens of pinball and other arcade machines—but the keys are missing. What are your options for opening the locks?
First, check my other page about opening pinball machines to understand where the locks are located and how they operate (which way to turn, etc).
Most pinball machines don’t use sophisticated locks. While many operators replace the default installed lock, these upgrades are not necessarily highly secure. Even security locks mostly require just more time and a better drill.
Disclaimer: This information should only be used to open a machine YOU OWN! Do not try these methods on someone else’s game (e.g., a game out on the street). Not only is this illegal, but the pinball business isn’t very lucrative anymore. Please respect the operators who continue to provide machines for public enjoyment, don’t give them another reason to stop!
Types of locks
As far as I know, nearly every pinball machine originally came with the same cheap lock model. It was up to the operator to install a more secure version. Many operators use a matching series of locks across all machines to simplify access with a single key. Leaving the default lock in place also meant that someone else with the same key could open their machine, since key combinations were limited.
I even read on rec.games.pinball that some manufacturers once shipped all machines of a specific game with identical locks, so one key could open every unit of that game type. So never throw out old keys, they might come in handy!
When I visited Tim Arnold in Las Vegas, he showed me his wall of keys. I believe he has every number of key for the default lock used on Gottlieb pinball machines, neatly arranged and numbered (from 1 to 999).
Here is a picture of a typical pinball lock. Most machines use a similar setup: just one small metal plate on the back of the lock, which catches the edge of the coin door. It's secured with a screw. Since the cabinet wood isn’t very thick, the lock itself isn’t very deep (about 3cm).
Default locks usually have flat keys, although some operators use round-key locks, which offer slightly better security. These cannot be opened with the screwdriver method, and picking them often requires special tools.
Lock Picking
Picking the lock is the cleanest method to open a door. People who know how claim it’s easy on pinball machines due to their simple design. That may be true, I just can’t do it myself!
If you want to learn to pick locks, search online. Plenty of websites and tools are available. But be cautious: lock picking tools are illegal in some regions, so check your local laws first!
Brute force
I saw an operator use this method on a machine he sold to me, although he didn’t have the key with him (and yes, he was the legitimate owner—not selling stolen property!).
He said the locks were cheap and susceptible to brute force. He began tugging on the coin door, and after a few minutes, it popped open! The metal latch inside bent just enough to release the door.
If you use a screwdriver or flat metal object, it's even easier: just wedge it between the edge of the coin door and the frame, and put pressure on the frame. Keep in mind this method WILL cause some damage to the door or frame.
The screwdriver method
Picking didn’t work, and you don’t want to use brute force that could damage the frame? If the default lock is still in place and it’s not a recent model, you might be able to open it using a large flat screwdriver.
Insert the screwdriver into the key slot and twist with force. Success may vary depending on your strength. The pins inside a default lock are made of soft metal. If you apply enough pressure, the pins bend or break, allowing rotation.
A similar method involves hammering the screwdriver through the inner part of the lock. This breaks the pins and lets the lock turn freely.
I've heard (but haven't tried it myself) that some people use a nail file. Using a thing metal nail file, it should be possible to damage the internal pins until the lock can rotate.
Drilling locks
This is my go-to method for opening any lock. Use a drill with a metal bit and drill straight through the center of the lock. It works for both flat and round-key types.
You have two approaches:
- Study the inner workings of a lock and drill only through the pins. These metal pins align with the key and control rotation. A small drill bit is usually enough for this targeted method.
- Use brute force: drill through the entire center of the lock. The screw holding the metal latch will eventually fall into the cabinet, unlocking the door. You typically don’t need to drill all the way—once the inner part is destroyed, the lock opens.
Locks use soft metals inside. I once drilled a modern “security” lock with a hardened metal exterior, but it was just a thin layer. It took extra time and a few drill bits to break through.
This method is effective because it only damages the lock. You’ll still need to replace the lock, but the coin door (which is expensive) remains intact.
Drilling a lock of a slot machine
Important Warning: Be very cautious when drilling the lock on a slot machine! Only do this if you purchased the machine without receiving the keys. Otherwise, avoid drilling!
Drilling a pinball lock is straightforward. Drill through the lock; the latch falls off and the coin door opens. There are multiple ways to do this:
- Use a large drill bit to destroy the inner rotating part—effective but messy.
- Use a medium drill bit and drill until you reach the screw securing the metal latch.
- Use a small bit and destroy only the internal pins—clean and minimal damage.
Slot machines and bingo games often contain more cash and are better protected. Instead of one small part, they use a full metal latch that locks the door along multiple points.
If you drill everything out, you risk not being able to rotate the lock or disengage the latch—making the door impossible to open without causing damage!
Here’s a picture of the slot machine lock I encountered. You must leave part of the inner mechanism intact to turn it. My lock used round keys, which are trickier. I didn’t know how the mechanism worked beforehand. I’m lucky I didn’t destroy the critical part. Had I drilled it completely, I might not have opened the machine at all.
Now that I understand the mechanism, I’d use a smaller bit and target strategic spots—just enough to allow rotation.
Note: Slot machine locks are deeper than pinball machine locks, so you may need to drill further in.
Why Brutal Drilling Doesn’t Work
Here are two images showing the internal mechanism of a slot machine lock. You’ll notice it doesn’t rely solely on one small latch. Instead, a long metal bar runs the length of the coin door, locking it in several places.
The first image shows the lock engaged (bar down), while the next shows it open (bar up). Several hooks secure the bar at different points. (left of the red lines in the first image) If you fully destroy the lock, the bar disengages and can’t move, leaving you stuck.
If you don’t know the exact mechanism and drill too aggressively, the only option left is to damage the machine exterior.
This lock is from my Bally slot machine made in 1966. Most slot machines use a similar system, though not an exact replica. But now you’re warned.
My Bally Safe Cracker pinball machine also uses a similar coin door mechanism. It locks not only on the side but at the top and bottom of the frame too. Lifting the door out of the frame won't work (or cause a lot of damage). Drilling through the lock completely will also leave the door locked at top and bottom.
Most vending machines (like Coca-Cola machines) use similar security: a large metal bar connected to the lock, which hooks into multiple frame locations. When drilling, you must leave a piece of the central lock intact to rotate and disengage the bar.
Fully destroying the lock causes the security hasp to loosen, and then you can’t open the machine without damaging the cabinet.
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