how do we replace upper vertical shaft gear #163987?
We have a Singer T&S Special Zig Zag model 648 bought in 1970. The upper vertical shaft gear has been ground down and runs rough and will not turn the bobbin. There are two part nos., 163328 and 163987. Are these gears the same, thus interchangeable? And are there any tips or techniques or special tools on changing this bevel gear on the end of that shaft? Or diagrams? Thanks.
Jim, August 2014
