Below is a picture of my Model 4E Jointer mounted on my Model 10ER. As you can see the Jointer's shaft does not align to the Headstock's Drive Sleeve. All Magna/Shopsmith Jointers from the Model 4E through the current model have the shaft from the Cutter Head in the same position and can be driven either by a pulley or the Hub and Power Coupler from a Headstock or Power Station. Having the Jointer mounted on the Jointer Mounting Kit you have to use the special Motor Pulleys and a Pulley on the Jointer. Incidentally the picture is showing a larger than 1-3/4" pulley on the Jointer as I hadn't found the correct one when it was taken several years ago when the Jointer was restored.
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Using Skip's SPT Mount and his special Drive Sleeve Pulley you should be able to use any SPT except the Mark Mount Planer on a Model 10. Do understand it may require different length Mounting Posts than the tool originally came with to achieve the correct alignment from the Headstock Drive Sleeve to the shaft of the SPT. Since Skip only has the one SPT Mount similar to the "A" Adapter you will have to adjust Mounting Posts for that. I cannot confirm if all the SPT's can work on this single Adapter. Skip would know.
The 2nd Power Mount Adapter Kit (see attachment PDF instructions below) came out as more Add-A-Tools (SPT's) were introduced and included an "A" and "B" Mount, the Special Headstock Pulley with Integral Hub and a pair of longer Mounting Posts for the Jointer. At the time all SPT's had straight Mounting Posts. Some with snap rings like the Jig Saw while others had stop collars like the Bandsaw. The stop collars allow more adjustment for use on the Power Mounts. Eccentric Mounting Posts could offer additional challenges.
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The original (1st) Power Mount Adapter Kit only had the "A" Adapter and was for use with the Jig Saw and Magna Sprayer. It was attached to the Base/Arm end of the Model 10 instead of the Headrest end and the original style coupler (no Hubs) was attached between the Quill's Spindle and the drive shaft of the Jig Saw or Sprayer. Due to their design and that of the Belt Sander they can be run from either side of the Headstock. The Jointer was to use the Jointer Mounting Kit and the 1st Power Mount Adapter Kit was designed for the Jig Saw and Sprayer. It was the addition of the Belt Sander and Bandsaw which prompted the 2nd Power Mount Adapter Kit and the Jointer Mounting Kit to be discontinued.

Power-Mount Adapter Kit 11-920 02-56.pdf