Introduction: Mills Vest Pocket Slot Machine Restoration

About: Design/Process Engineer who loves to make things

While cleaning out my grandparent's basement after the passing of my grandfather, I found an interesting 1930s nickel slot machine that was in rough condition.

The (ugly bright orange) paint was chipping off and the coin slot would not push in far enough to activate the mechanism inside.

As a prospective mechanical engineering student in college, I saw this as an opportunity to test some of my skills while also learning about mechanisms that were made around 80 years ago.

This project was also appealing since it is very similar to the premise of the History Channel TV series "American Restoration", of which I am a fan.

Step 1: Disclaimer

As a precautionary measure, I would like to stress that this Instructable will NOT be a perfect guide to restoring a classic slot machine to original, mint condition. This was a project that I embarked on to have some fun and put my skills to use.

The idea of making the slot machine functional and visually appealing also meant that I could potentially sell it sometime down the road for a nice chunk of change.

I simply did what I thought should be done in order to get the machine to a state where I would be happy with it. I'm not sure how I will affect the true value of the machine, but this project is more about the restoration journey than the monetary destination.

Step 2: Planning

Just like all good projects, this one began with me making a plan-of-action for restoring this slot machine. The key points I wanted to cover are:

- Get internal mechanism working
- Repaint outside of slot machine
- Clean worn/dirty parts
- Replace viewing window glass
- Replace reel strips

Step 3: Research

By reading the various markings on the slot machine, I was able to do a few quick Google searches to deduce the name and brand of the slot machine, as well as any other info that might be useful down the road.

It turns out that it's a "Vest Pocket" slot machine produced by the Mills Novelty company in the 1930s and 40s. Its claim-to-fame is that it is the smallest slot machine of its kind ever produced. It was also cleverly designed with a flap that covers the viewing window so that the reels and the machine's identity as a slot machine can be hidden.

After a few more google searches I was able to find a PDF version of the original owner's manual for the Vest Pocket. This helped me on several occasions with its diagrams of the slot machine's mechanism as well as tips for maintenance and repair.

This document can be found here:

Step 4: Tools and Equipment

- various size screwdrivers (mostly flathead)
- metal scraper
- various grits of sandpaper
- metal wire brush
- good lighting
- WD-40
- white vinegar (if rusting)
- primer
- paint
- clear coat
- painter's tape
- Adobe Illustrator (any similar drawing program will work)
- 1/8" Acrylic sheet

Step 5: Disassembly

One of the great aspects of this slot machine is that the entire mechanism is one unit that can be easily removed from the casing through the back panel. Once the internal mechanism was removed, I unscrewed the remaining parts attached to the casing such as the top and front flaps, the viewing window glass and its retaining bracket, and the rubber feet on the bottom.

Step 6: Fixing the Mechanism: Part 1

After removing the internals of the slot machine and inspecting its parts, I figured out that the coin slide was not pushing in all the way because a nickel was jammed inside one of the parts.

By taking out a few small screws I was able to use a hammer and a few small flathead screwdrivers to open the gap between the two parts wide enough for the nickel to fall out. With this jam cleared, the mechanism actually began to move for the first time.

Step 7: Fixing the Mechanism: Part 2

Now that the nickel was out of the mechanism, I was able to observe and play around with the different parts to see how they work together. I then used the diagrams from the owner's manual to check for missing parts. Seeing that nothing was missing I figured I would try to put a new nickel in the mechanism and see how it would work.

Long story short, it really didn't.

Step 8: Fixing the Mechanism: Part 3

Surprisingly, many of the parts actually did work, despite decades of disuse. The coin slide was now moving after clearing out the jammed nickel, and the fingers that stop the reels were clicking into place.

Unfortunately though, the reels wouldn't start spinning when they were supposed to. Reading through the owner's manual, I figured out how the reels were supposed to start spinning. When I examined the machine, I noticed that a small spring on the arm that turns the reels was deformed. After replacing it with a new one, the reels started spinning.

Step 9: Fixing the Mechanism: Part 4

To get everything working smoothly, I next used some WD-40 to lubricate all of the parts that move and grind against each other. I paid special attention to the gear train, as it has many teeth that grab each other and create lots of friction.

Step 10: Fixing the Mechanism: Part 5

After lubricating the mechanism I made some final tweaks like cleaning off parts and replacing springs. I also followed the owner's manual on how to fill the mechanism with nickels to prepare for play. I then began testing the mechanism to make sure everything was working correctly.

Step 11: Mechanism Testing

After emptying my coin jar of nickels, I read through the owners manual to see how to prep the mechanism for play. Without going too far into detail, I basically had to fill the retention cylinder with roughly 40 nickels, so that the mechanism would have enough to pay out if a person won.

Since the mechanism was now completely functional I spent probably 30 minutes playing it to make sure everything was running smoothly. This was actually one of the most rewarding parts of this project, since it was the first time the slot machine had worked in decades.

A video of me testing the slot machine can be seen on YouTube here:

Step 12: Replacing the Viewing Window

The old glass pieces for the viewing window were yellowed and cracked, so I traced them onto a sheet of acrylic and cut out two new pieces. I then test-fitted the new pieces and sanded them so that they would fit perfectly inside the bracket.

Step 13: Cleaning Parts

Several parts on both the inside and outside of the slot machine were rusting and/or covered in dirt and grease. To clean the dirty metal pieces, I used a metal wire brush and high grit sandpaper to remove dirt spots and reveal the shiny metal underneath. I then washed the parts with soap and warm water to clean off any remaining dirt or metal shavings.

The top flap that shows the payout combinations for the slot machine was rusting, but the paint on each symbol was still good. Since I wanted to preserve the original paint, I soaked the flap in white vinegar over night (roughly 12 hours) to help lift off the rust. I then used a small flathead screwdriver to scrape off the remaining rust, followed by sandpaper to restore the shine of the metal.

Step 14: Making New Reel Strips

One interesting aspect of the slot machine was that the symbols on the spinning reels were hand-painted onto a strip of paper on each reel. While this helped add to the 1930s era look, the symbols were fading and the paper was disintegrating.

While doing research on Ebay, I came across an auction for 3 printed paper reel strips for a Vest Pocket slot machine. Instead of paying the $15 and waiting for them to be delivered, I decided to make my own.

By using some simple math, I was able to figure out that the circumference of the reels is 7.5" while the width is 5/16". I then divided the circumference of 7.5" by 10 to get the spacing between the symbols, which is 0.75".

Using the program Adobe Illustrator, I then drew up my own reel strips, using a combination of symbols taken from the internet and some of my own design. I then printed them out on regular printer paper and laminated them so that the paper and the ink would last longer.

Step 15: Removing Old Paint

During the research phase of this project, I found it odd that I couldn't find a Vest Pocket online with the bright orange paint that mine had. This lead me to believe that the machine had been repainted at some point in the past.

This was actually a great advantage for me, since this already-flaking orange paint was easily removed by using a metal scraper. Once all the paint was removed, I sanded all the pieces until they were smooth.

Step 16: Prepping for New Paint

To prepare for my new paint job, I unscrewed and removed both flaps on the casing as well as the lock mechanism on the back panel. After taking all the paint off, I used various grits of sandpaper to remove any dirt and grease while simultaneously smoothing out the surfaces. This was done to all sides (inside & out) of the casing, back panel, top flap, and front flap.

I then sprayed 3-4 coats of primer (letting it dry for 10-15 minutes between coats) over everything so that the new paint would adhere well to each part. I chose to use Rustoleum brand spray primer simply because it was the best choice for this type of project at my local hardware store.

After the primer was completely dry, I sanded the pieces very lightly to smooth out the surfaces in preparation for paint. I then used a damp paper towel to wipe off the parts before painting again.

Step 17: Applying New Paint

Since blue is my favorite color, I chose to use a dark blue with metal flake to paint the slot machine. I again used Rustoleum brand spray paint and gloss clear coat to give the slot machine a case befitting of it's refurbished internals.

I sprayed on 4-5 coats of color, letting it dry for 10-15 minutes between coats. After the color dried over night, I sprayed 4-5 coats of clear, again leaving 10-15 minutes between coats.

Step 18: Reassembly

Once the paint had dried completely, I used some more WD-40 for final lubrication. I then screwed all extraneous pieces back into the case including the viewing window, top flap, front flap, and door lock. The entire mechanism was then put back into the case, and the door was locked shut.

Step 19: Finished Restoration

Overall this was an extremely fun projected that spanned roughly 3 weeks including weekends and nights after school. The sheer amount of satisfaction that came along with restoring an old, worn out machine and bringing it back to life is indescribable.

I was able to utilize many engineering skills that I've learned over the years to completely restore this 1930s slot machine. I was able to fix the internal mechanism back to working order, clean dirty metal parts back to original shine, repaint the shell and make new reel strips with custom symbols.

This project was so fun that I may attempt another restoration in the future should I find another item in need of help.

I also want to dedicate this project to my grandfather, whose slot machine it was, and who passed away this past summer.