Not every machine can be set up with a hand crank. And you need a 9 spoke hand wheel. Singer made/sold machines with just hand cranks. The rail to which the crank was mounted was later used to mount a motor. I have never seen an original Singer hand crank in person, but the ones I've seen for sale (e.g. on ebay) are expensive. The reproduction hand cranks are all about the same, but they can be improved somewhat, i.e. opened up and greased.
Here are some threads on hand cranks:
Question about Bobbin Winder on Singer 99-13? - Quiltingboard Forums
Aftermarket Handcranks - Quiltingboard Forums
Hand Crank for Singer 27 - Quiltingboard Forums
Singer Model 99, Conversion to Hand Crank - Quiltingboard Forums