When the quill lock wing nut is 'tightened' is compresses the wave washer until it is flat. Further tightening moves the sleeve against the domed washer that then bears against the interior web in the headstock. Without the woodruff key between the sleeve and the quill advance shaft hardly anything is resisting rotation of the shaft. The woodruff key provides a solid link between the shaft and all that stuff that is being squeezed. All that stuff does not want to rotate as the domed washer is acting like a brake disk.
I would start by looking for 1/8" thick keys.
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
