I was looking for a retail display for necklaces, but none did everything I wanted.  My list was:

1. Adjustable
2. Modular

I took my design for the Dragon Display that I make and modified it for use with necklaces, bracelets or anything else you want to hand from a bar. You can check out the dragon tower here:

https://makerworld.com/en/models/1186054-display-tower-for-your-dragons#profileId-1197074

The base has a diameter of 253mm making it stable enough to hold the display stable.  There are 4 recesses in the bottom to allow you to add 12.7mm rubber pads to prevent the stand from shifting.  I use these pads. 

Scotch Clear Adhesive Bumper Pads 40 PCS, Self-Stick Rubber Pads 1/2" Round, Cabinet Door Rubber Bumpers, Designed to Protect Cabinets and Drawers, Sound Dampening, Transparent (SP951-NA)

https://a.co/d/dgrOg7h

I have this designed to allow you to create a display for different length neckalces.  If you use the just the base and top shaft, you can display a necklace that hangs about 12 inches (300MM) down.  You can add an intermediate shaft to raise the top about 4 inches (106MM) higher.  

You can really keep going however high you want.  You could also make it to have two spinning display arm sets allowing two different display areas.  Maybe bracelets on the top and necklaces at the bottom.  The possibilities are limited by you imagination. 

The spinner is my favorite part.  You can choose between 4 or 8 arms, and of course, they can be changed at will.  Each spinner is made of 3 components; top and bottom mount and hangers.  The mounts have slots and notches aligning the arms in the correct locations.  You simply insert the ends of the arm into the bottom circle and then sandwich them with the top.  Everything is just press fit and they hold together well.  The next shaft or top with keep them together.  The arms are build with strenght in mind, but if one does break, it is very easy to replace and move on.  

Building the whole display is pretty straight forward.  

Screw your desired length shaft onto the base.  After assembling the spinner, put it onto the shaft.  Screw the next shaft on and tighten until it reaches the spinner.  You can adjust how free the spinner moves by simply loosening the shaft by a little bit.  The nature of 3d printed threads allows for a “notched” feel, so once you have it set, it stays that way.  Now you just add another shaft, then spinner and finish it off with the top.  

I have two tops to choose from.  One has a notch for any sign you design, it just needs to have a 5mm base to fit into the slot.  There is also a top without a slot if you don't want to add a sign.  

As always, likes, collects, downloads and boost help me keep moving foward with designs.