I have been working on a project in a library. I am able to take a drink cup, but sometimes am short a hand for managing doors while carrying everything. This carrier suspends my cup from the bag for my supplies. A cup could also be suspended from a belt loop or a lanyard around one's neck.

Materials

3/16 inch rod
Links from 3/16 inch chain

Tools

Caliper
Hammer
Vise
Hacksaw
Welder
Grinder

Step 1: Measure the Cup

I used a caliper to determine the diameter of my drink cup in the area where I wanted to steel ring to support the cup. If the ring can be as high as possible, the cup will be more stable. This cup looks like a paper throw-away, but is actually plastic and double walled. It is from Bed, Bath, & Beyond.

Step 2: Bend the Rod to Fit the Cup

The rod may be formed around a piece of steel pipe. Instead, I made small crimping bends and fitted the resulting curve to the cup, making adjustments as needed.

Step 3: Does It Fit?

My plan had been to multiply the diameter of the cup by п (3.14). I even allowed a little extra, but still came up short.

Step 4: Chain to the Rescue

I cut the end from a link of chain and welded it to the two open ends on the ring. (At the end, I welded a short piece across the link of chain to keep the handle from sliding down around the ring.) The chain link allowed some final adjustment of the ring size. I could squeeze the chain link in a vise to make the ring a little smaller, or I could drive a wedge, like a cold chisel, inside the link to spread it and make the ring larger.

Step 5: Bend a Handle

I bent the end of a piece of rod like a shepherd's crook. The tool I used is described in this Instructable.

Step 6: Attach a Chain Link to the Handle

I opened another link of chain enough to slip the end of the rod handle into the opening. I slipped the link of chain over the link that closes the ends of the ring. I welded the handle rod to the chain link.