(Full disclosure: I know parts for both models' are pretty much discontinued for the most part but this was a foray into what may or may not work ) I just completed partial rebuild of each model, 29-4 circa 1915 and Adler 30-1 circa "who knows"(black paint/cast iron stand, no decals) feed motion area and thought I'd pass on what I found.  Stitch length was far from optimal but little or no play in either of the machines' Driving Lever(s) so I felt driver cam was within functional specs.  I