Here are the pictures of my shoulder mount set-up on my Etrac. I removed the foot rest and arm-cuff. Used the screw from the arm-cuff to secure a small piece of aluminum bent at a 45 degree angle for the upper attachment point. Along with the anchor I cut a small piece of plastic to completely cover the open slot in the base where the arm-cuff was to keep dirt out. The shoulder strap, padded with swivel clips, was from an old carry bag, and the lower attachment is a velcro tool holder thingie from a big box lumber store.
I was able to use the entire Etrac lower and upper shfts because the first mod I only used the lower shaft and REALLY missed the infinite adjustment of the original. I found that the 7/8 (OD) inch rod of an old Tesoro MD fit so snugly into the shaft of the etrac that I prolly won't even drill and pin it. Could have put the coil wire inside by cutting a slot for it to exit but leaving it on the outside makes changing coils SO MUCH faster. I also found that the stock Koss HF where nice to use with their short cord because the machine never leaves my shoulder while MD so the short cord actually works out good. I even used my smaller ear buds with great success as the cord just lies on my back out of the way. All this was done with out one single permanent change to the Etrac. When digging the machine is slid over to my left for full access to the hole. The only change to what I useually have do is the coil and shaft is placed on my left instead of my right,,,,,,
I was able to use the entire Etrac lower and upper shfts because the first mod I only used the lower shaft and REALLY missed the infinite adjustment of the original. I found that the 7/8 (OD) inch rod of an old Tesoro MD fit so snugly into the shaft of the etrac that I prolly won't even drill and pin it. Could have put the coil wire inside by cutting a slot for it to exit but leaving it on the outside makes changing coils SO MUCH faster. I also found that the stock Koss HF where nice to use with their short cord because the machine never leaves my shoulder while MD so the short cord actually works out good. I even used my smaller ear buds with great success as the cord just lies on my back out of the way. All this was done with out one single permanent change to the Etrac. When digging the machine is slid over to my left for full access to the hole. The only change to what I useually have do is the coil and shaft is placed on my left instead of my right,,,,,,