I initially thought your title was a typo as I couldn't find a manual at
https://www.singer.com/manuals I know some have used tandtrepair for slant needle machine parts and books and found him to be helpful. I think you are referring to the rubber feed dogs as seen at
http://site.tandtrepair.com/SingerFeedDogs.html I couldn't find a manual or other info for a 728 on that site. I did find a manual for a 708/728 at
http://www.sewingmachinemanual.net/S...ion_Manual.htm and
https://www.sewusa.com/Sewing_Machin...ng_Machine.htm and
https://manualsoncd.com/product/sing...uction-manual/
Janey - Neat people never make the exciting discoveries I do.
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