This is how you'd like your mandolin to be when you're playing, right? But what happens if I let go of the neck?
Oops! The mandolin has fallen to its naturally balanced angle. This is called "neck drop", and can happen with guitars, basses, and other instruments in the mandolin family too. David Benedict highlighted the problem in a Facebook post in September 2023. It only happens if you have the strap connected to something at the top of the body, such as the scroll, rather than to the headstock.
The problem can be simply fixed with a short piece of thin shock cord tied in a loop. You could also use leather cord (AKA thong),or maybe just a boot lace.
That's it! I used elastic shock cord that's 1/8" thick (3mm). Just tie the end of the strap to your belt. You have to experiment to get the cord the right length, as is depends on what height you have your mandolin on its strap.
Notice how I have connected the cord to the pin hole-and-slit in the end of the strap. On my first attempt I just looped the cord around the whole strap, but there was a danger of it pulling the strap off the mandolin altogether. That could be disasterous!
This method looks quite neat, but if you prefer to have your shirt hanging outside your trousers (pants),it can look untidy. Here's an alternative way of attaching the cord:
Here I have actually put a hole in my jeans! I made it neat by adding an eyelet (grommet) and it looks pretty cool. I've had to use a carabiner hook so that I don't have to tie and untie the cord loop every time I play the mandolin. A large size safety pin, kilt pin, or some other kind of clip would do as well.
Let me know if you come up with better ideas. David Benedict tried a solution devised by Josh Pinkham which involves hanging a 2lb weight (1kg) off the bottom of the strap. This seems to work OK, but it looks like a pretty clunky solution to me. Each to his own!