Originally Posted by Weedwoman
Originally Posted by luv2learn
Are all cams machine specific, or are they interchangeable from one cam using machine to another?
I think they are machine specific but some models may use the same cams I'm not sure on that one. Billy would know. My 306k has to have the zz cam in even if I just want to do a straight stitch, don't know why.
In the Singer line, they are somewhat interchangable. There are several machines that use the black cams, and then the later, 60's-70's model machines used white cams. You can use any black cam in a black cam machine, and any white cam in a white cam machine, but you can't use white in black, or vice versa.
Some of the models were made with some basic built-in stitches, and then took cams for extra sts beyond that. Other models were made with NO built in sts, and it took cams to create all the sts. That would be why you need the basic ZZ cam in place to sew a straight st.
This is the basic difference between the 401 and the 403. The machines are identical except that the 401 has some built in sts (hence the big dial button, front and center) and also takes cams, and the 403 has no built in sts, and uses cams for all sts. I believe the 500a and the 503 Rocketeers are the same way-- one has some built-ins and the other has none.