I have made some 3D printed upgrades to my 1949 Singer 29k-71 which can be used on other versions of the Singer 29K as well as other machines like the Consew 29, Cowboy CB29, Cobra 29, Techsew 2900 to name a few. The upgrade requirements: i) Simple ii) No holes to be drilled or tapped into either the sewing machine or the cobbler base. iii) Installed / removed in under 5 minutes with no special tools. 1) Photo 6 is a view from the pulley wheel side showing a Double 1 pound spool thread