Anastar wrote:

The typewriter is a late-30s Royal portable. The bell doesn't ring until you only have three spaces left. How can I get it to ring when there are 7 or 8 characters instead?

I think the problem might be with this long piece that hangs off the right margin stop. It swings and dangles very loosely. Or is it supposed to dangle and swing like that....?

I don't see a model number on the typewriter, but it looks like this.
 

The model is "Aristocrat". There is no number associated with that model, although it is very useful to also give the year when talking about it because Royal used the Aristocrat name over decades for very different designs.

That piece you show relating to triggering the bell is supposed to be dangling and swinging loose, so that it can ride over the trigger lever with no resistance while returning to the left (viewed from the back) and resetting. It firmly moves the clapper while moving to the right (viewed from the back) and easily slides over it while returning.

The trick to setting the number of spaces before triggering the bell does involve that piece, which is attached to the right margin stop, and the position of bell clapper linkage. Inspection while operating the carriage back and forth in that area will show you how they are related and will suggest what you can manipulate to change things. There are no adjustment screws to do this; it is a matter of bending things to change their relations. Unfortunately, this usually affects the clarity of the bell, so it can be frustrating.

(It has always been a mystery to me how some typewriters have only a three-character warning and i have not ever actually changed that.)