Deep Hole in a Small Box, a Different Take on the Infinity Mirror.

First off I must give credit for the inspiration to these two Reddit posts, this is the first one I saw and this is the one that inspired that first one.

Having seen these I knew it was something I wanted to make. I hope this Instructable inspires you to pick up the tools and give it a go.

I completely messed up my first attempt by trying to use some beach and ash offcuts that I unsuccessfully jointed, this is version 2 and so much better.

The final product is impressive, even if I do say so myself.

Most of the supplies will depend on the size of the box you're planning to make.
I used some really nice B/BB plywood, this is such a great material and so different from the 'normal' plywood you get from the big box stores. Very few (if any) voids and with the B grade face it's pretty much blemish free. It's a little heavier and quite a bit more expensive, I would say it's worth it for any 'public' facing project.
The size of the box I made was determined by the mirror that my wife was throwing out, this was used as the bottom mirror.
You'll need enough wood (ply) to make the four side of the box to a height of about 325 mm (13 inches).
I decided to go for a bulkhead light for the inside of the box as I thought this was in keeping with a mine shaft. You'll also need a length of mains cable.
The bottom mirror is a standard mirror but the top is where the 'magic' happens.

To reinforce the bottom mirror I mounted it to a piece of 4 mm plywood using some double-sided carpet tape.
This gave a total thickness of 8 mm, you'll need to remember this measurement for later as this is the size of the router bit you'll need for the rabbet.

I had originally planned to get an old ladder and chop one of the rungs off. After searching Gumtree, Facebook marketplace and local skips I didn't manage to find anything cheap enough (free).

I wasted so much time looking around, it actually took me less time to make a quick single rung ladder.

Using a couple of 70 x 50 mm pine offcuts and an old broom handle I knocked up a little single rung ladder.
I distressed the pine by knocking it about with a hammer and painted it black to add to the mine shaft authenticity.

The height of you ladder will be determined by the space between your two mirrors, you want to make sure the ladder is tight up against the top mirror as any large gap will ruin the illusion. You also want to make sure the rung is in the middle for the same reason.

As I do with most projects I drew up the basic plan first. I've attached the Sketchup file of the plywood layout.

For added strength I decided to join the sides using super sized finger joints, to do this I made a quick jig, this allowed me to make multiple blade passes on my table saw, these were also at an exact 90º.
I started by measuring the end of the long sides and dividing it by 5 to get the size of the fingers. These were then marked out on both ends of the two longer sides. Once I had made the cuts to make the fingers I then used the cutouts to mark up the corresponding fingers on the short side pieces.

Using the cutouts to mark up the second pieces ensures that the fingers line up.
I dry fitted the box together to ensure a good fit before the glue up.

Using an 8 mm router bit mounted into my router table I routed a slot for the bottom mirror around the bottom of each of the four sides. In the shorter sides this slot was stopped before the edge, so I was not visible from the outside.

In one of the short sides I cut a 50 mm hole, this is centred around the bottom mirror slot, it's to allow the mains cable to pass past the mirror, through to the light.

Again, another dry fit, this time with the mirror in place.

I then routed a slot all around the top edge of each side, this slot was 4.5 mm deep as I was planning to use a 4 mm top mirror. The slot was cut to half the width of the sides, this gives the top mirror enough area to rest on.
All the top slots were stopped to line up with the corresponding slot on the joined piece.

Once I had routed the slot around the inside top edge I was able to measure up to get the top piece of glass.

I went to my local glass / mirror centre, having given them the measurements and told them what it was for, they strongly recommended I got toughened glass. This is a service they offer but there was a week delay.

Having collected my new piece of toughened glass it was time to make the top mirror.

Unfortunately I didn't get any pictures / video of me making the actual top mirror.
It took two attempts as I completely messed up the first one, I hadn't cleaned the glass well enough and managed to stick the mirror film to itself and crease it. I decided not to film my second attempt as I really needed to concentrate.

I'm pleased to say the second attempt went much better and I now had a serviceable top mirror.

Please take the time to watch the video, even if it's just for the trick on how to remove the mirror film backing.

All the sides had now been finished it was time to glue up the box.

DON'T FORGET TO PUT IN THE BOTTOM MIRROR. If you do you won't be able to add it in later. I also put the top mirror in place to make sure the box was square around it.

I used Titebond 2 wood glue but any PVA wood glue would work fine. Make sure you cover all the mating surfaces, if like me you're using plywood, make sure you use enough glue as the ply is thirst and you don't want a dry joint.

As shown in the second picture I made two corner blocks to allow me to put some clamping pressure across the box to square it up.

The box was then left for the glue to set.

The following day I sanded all the outside faces.

To the outside faces I applied 3 coats of Danish oil, sanding lightly between coats.

Again to maintain the illusion of the mine shaft I clad the inside of the box with some unfinished shiplap.
This was a great find because it was out of the bin at the timber merchants.

After this I hot glued the bottom of the ladder into position on the bottom mirror. I also ran a bead of hot glue down the back of each leg to hold it to the side.

On the opposite side to the ladder I passed the wire through the hole up to the bulkhead light. This was wired and screwed to the side, a 6 watt LED was installed and the top put on.

To lift the box off the floor I added some feet, these were made from some plywood offcuts.

The main reason was to allow the mains cable to pass out of the box without being squashed and damaged.

The end result was superb and exactly what I was hoping to achieve.

It must be convincing because I showed one person who proceeded to look under the box to see how this 'magic' was being done.

The 'magic' of this is how a 'one way' mirror works... As it was explained to me by the guy in the mirror shop is that the refection is always on the side of the mirror with the most light. This is why the police turn off the light when they are observing the interview from outside.
On the table when the light inside is off it just looks like a mirrored top, when the light is on you get the internal reflections, this is even more effective when the external light in the room is off too.

I hope this has inspired you to have a go too.