Intro: Creating a Jig for the Repeating Unit Bracelet
After making the Repeating Unit Bracelet shown in another of my Instructables, I decided that it would be useful to have a sturdier platform to use both to design the bracelet and to do at least one side of the rivets. This jig facilitates the process.
Tools and Materials:
- laser cutting machine (I made this at the TechShop: www.techshop.ws)
- vector art software
- USB stick
- 1/8” thick clear acrylic (min: 3-1/2” x 10” sheet)
- (4 or 5) 1/2” long, 1/4"-20 set screws
- (4 or 5) 1/4"-20 nuts
To make the jig:
1. Download the attached PDF and import it into whatever vector art program you are using to interface with the laser cutter. If you are using bracelet shapes that are different from those shown, where the area around the wire holes might be more than 3/8”, be sure to redesign the jig to move the set screws further away from your working area.
2. Cut out the acrylic pieces on the laser cutter. The bottom layer has only five holes; these accommodate the 1/4"-20 set screws. The middle layer has these five holes, plus eight small “channels” for the bracelet wires. The top layer again has the five larger holes, plus eight smaller holes for the bracelet wires.
To use the jig, follow the basic instructions in my Repeating Unit Bracelet Instructable, with the following modifications:
1. Cut the eight wires to whatever height you want your bracelet to be *plus* 1/2”.
2. On each of the wires, bend over ~1/8” on the end (not longer, and not much shorter), making sure that this small “hook” fits in the channel of the middle layer of your jig.
3. Assemble the jig by putting the long end of the wires through the top layer of your jig. Arrange the short ends radially, and add on the middle layer of the jig. Once you have the two layers seated fully, add the bottom layer of the jig. Screw the jig together with the 1/4"-20 hardware. I found that I didn’t need the fifth set-screw in the middle. If your hand is bigger, or your pieces are substantially larger, and you have to modify the overall spacing on the jig, you may want to use this middle hole to clamp the jig more securely.
4. Once you have assembled your design, tap the wires down to fully seat them in the channels of the jig; you want to be sure there is no slack for the wires to move while you make the top rivets.
5. Cut the wires off to *2x* the wire diameter above the bracelet pieces. This is substantially more than what you would leave to make rivets normally, but you will be making a “free-floating” rivet head, and accommodating any further slack in the wire being fully seated in the channels.
6. Make your top rivets. They should be substantial enough to keep the pieces from sliding off of the top of the wires, but they don't have to look especially pretty yet (if you *can* it will make the process easier, but you can also finish them at the same time you are finishing your bottom rivets). They will be “floating” above the top bracelet pieces by ~1.5x the wire diameter.
7. Disassemble the jig, noting that only the bottom layer will come off of the bracelet easily. The middle layer is still held to the top layer by the small bends in the rivet wire. While holding the jig in your hand, tap the top rivets until they are flush with the top bracelet pieces. This will free up the small “hooks” that were in the channels. Place the bracelet top-side down on your working surface. Cut the exposed “hooks” off with side cutters, and remove the middle layer of the jig. Remove the top layer of the jig.
8. You will have more wire sticking up than you need to make your bottom rivets. Cut the wire off to half the wire diameter above your bracelet pieces, and proceed as before in the basic instructions to finish the rivets on the bottom side.