There a many styles of saddle stops but most are light duty for small lathes where adapted micrometer barrels may stand the strain with their fine threads.
This one is was inspired by a Colchester lathe I used to use and would stay put even under auto feed trip loads.
Easily made on the lathe from 2.125 diameter bar stock 1.5 long and uses a .5 x 20 tpi UNF thread giving 50 thou per turn and a travel of 1.25 inch.
The spring clip on the end of the feed dial merely serves as a friction device and also keeps the dial in contact with the block.
I have a set of home made setting discs in common sizes to compliment its use, particularly when milling in the lathe where the top slide is of no use.
This one fits a South Bend but sizes can be tailored to suit your machine.