I would think to make one one would need to find a sprocket that one could modify to attach to the saw spindle and I would think it would be easer to modify the base to bolt the bar on to, and then align, if one want to use the worm drive saw,
the simplest may be to buy a replacement sprocket from that company,
the baileys company has many sprockets and set up for nearly any thing chain saw related, on larger chain saw there is what is called a rim sprocket and it is seperate from the drum/clutch, for cheaper and easer drive replacment,