(1) Empty Altoids Tin
(3) Rulers, paint stir sticks, or I used banister rail spacers
(3) Guitar Strings (I used the top 3)
(1) Old BIC pen
(1) Some plastic (credit cards work well)
(3) 3/16 x 2 Eye bolts
(1) 1/8 mono jack
Drill with various drill bits
Hot Glue Gun
Make sure to outline the areas of the Altoids tin before you begin cutting. You need to make one cut at the base of the tin for the first ruler to slide into (see pic, sorry it's fuzzy).
WARNING! Make sure you are cutting on the correct side. You want the nice Altoids logo to be displayed correctly when playing it. I am right handed, so I made the cut on the right side of the tin.
I used a drill to put holes in the box. Then I used a small knife on my multitool to cut the box out.
Now you need to make holes for the strings. Again, mark the holes before you break out the drill. I used a 3/32 drill bit for this.
You also need to make a hole for the 1/8 jack. I used a slightly larger drill bit and then bored out the hole with a pair of needlenose plyers.
Now we are going to cut up a BIC pen. This will be used for the strings to rest on (instead of the side of the Altoids tin). You need to cut it down to about 1 and 1/2 inches in length. Then cut that in half and trim it down to fit on the end of the tin.
I also put 3 notches in the pen for the strings to rest in.
After that, get out the hot glue gun. Apply a nice layer of glue on the BIC pen piece and put it on edge of the lid, above the strings (see pic)
You need to attach the 1/8 jack before you insert the neck. You want to make sure everything fits correctly. I mounted the 1/8 jack and put an adapter in it to be 100% sure everything would fit.
NOTE: If the ground plug touches the case, this will not work.
After you know everything will fit, put some Gorilla Glue on the bottom of the case and slide in the ruler (only 1/2 way or as far as you can go without hitting the jack).
After that glue was set, I covered the whole thing with glue from the hot glue gun. Just to seal everything up and make sure the ruler will not come apart.
Cut the plastic (an old Skype card worked for me) down to the width of the rulers. Bend the plastic. We are going to insert this between the top and middle rulers to guide the strings. You will want to make the bend a little larger than the height of your ruler.
Cut the other 2 rulers you have down about 1 inch smaller than what is sticking out of the Altoids tin. Get out the hot glue gun. Glue down the first ruler. Then glue the plastic down with the tab sticking up. Then glue down the final ruler on both the plastic and the middle ruler.
Now we need to add holes for the eye bolts. Measure and mark before drilling. I used a 3/16 drill bit. You want to make a V with the bolts. Put two close to the neck and one on the end. Then, insert the bolts with the nut and washer on the top side. One nut will go on the bottom (you can add washers if you want more support).
Break the piezo from it's case. Be careful not to damage the piezo in the process.
Once it is freed, wire it to the 1/8 jack. Follow the diagram that came with your 1/8 jack to find out which is positive and which is negative.
Before I glued it to the case, I drilled a very small (1/16) hole in the lid. Center the piezo on the hole in the lid and hot glue it down.
Now we just have to string it up. Insert strings into the holes on the end. Once they have all been inserted, close the lid. Loop each string over the BIC pen and then thread them into the eye bolts. I looped the string 3 or 4 times in the eye, then allowed the slack to twist around the body of the bolt.
To tune, just turn the eye bolts to add tension to the string. Then tighten the nuts to keep the bolt in place.
Then plug in and play!