Columbia's Collar

Here's what I used to make this:
1 External Tooth "Lock Washers" 1/4"
10 External Tooth "Lock Washers" Size #10
1 Knurled Nut Size 6-32
1 Screw size 6-32x3/8 (to secure the knurled nut)
10 Rhinestone Rivets 7mm
1 Jewelry Ring (about 5/8" diameter)
1 Jewelry ball with hole through it
1 Buckle (I used size 5/8")
Strip of leather cut 5/8" wide x 20" long (or you could use vinyl if it's thick enough to hold the rivets)
Gold spray paint (because most of these parts are silver)
1/8" Drive Hole Punch
3/16" Drive Hole Punch
...and a hammer

I cut my leather just a smidge over 5/8" with a rotary cutter and straight-edge, then I edge-stitched it on my machine with heavy-duty thread and a size 16 needle (I actually have a leather needle, but couldn't find it anywhere!!)

To install the jewelry, I made 11 holes with the 1/8" drive hole punch spaced 3/4" apart - the ring goes in the middle, and then 5 rhinestone rivets on each side.  Each rhinestone has a size 10 lock washer behind it (painted gold).

The center ring-piece is assembled as follows:  1/4" lock washer on the bottom, then the knuted nut with the ball glued to the top and the ring inserted through the ball.  Once the glue has cured you can paint the whole assembly gold/brass.

I secured the ring assembly to the center hole with a  size 6 screw from behind.

At one end I punched a 3/16" hole about 2" from the last rhinestone to install the buckle.  Then I used the smaller punch to secure it with a rivet.  At the other end, beginning about 1-1/2" from the last rhinestone I punched 4 3/16" holes to make the collar adjustable.

ETA:
Stainless Town has both sizes of Lock Washers (for pennies each), and the flat screws that fit into the knurled nut, which you can find at The Nutty Company.