For a cheap and nasty fix you could use some .03 or so diameter soft iron wire wind it in the groove and around again and twist it lock it in place. Cheap and nasty but it works.
Home Depot sells these 'C' clips in those triangular rotating bins they have in the fastener section.
For real economy you should get the set in ala_xfires post, that can't be beat for value.
It's such a bargain I might buy them even though I do not need them.