Brother KH521 knitting machine is a 4-push button machine with 200 needles, spaced 4.5 apart.

I just became an owner of the KH521/KR321 setup so stay tuned while I am putting my notes together and scanning a copy of the manual.

It was manufactured in the early 1960s. It is possible that it was released for the Japanese market only judging by the number of writing on the packaging, on the machine and on the carriage in Japanese.

I personally did not have a chance to work on this machine but it is very similar to other 4-push button machines, like Brother KH531 and KH551. Thus, it should operate similarly and have the same pros and cons.

The Brother KH521 knitting machine can be matched with the Brother KR321 ribber.

Because of its similarity with KH551, Brother KH521 might be compatible with the  Brother KR551 ribber.

Below are the pictures from the Internet published with permission.