I have a patcher 29K51 sitting in a repair shop and all work has stopped, because we can't find the last missing piece to get this machine to work…it just will not produce a stitch! 
Apparently we need a new gear box (the long thing sitting underneath the patcher's arm). 
So far, I have not been able to find one. 
Does this gear box have to be made for the K51 only, or is it interchangeable with other singer patcher models? 
I am not even sure, that it really needs a new gear box…perhaps the timing needs to be adjusted…but how? 
Any thoughts on this mystery would be greatly appreciated! 
Eleni