bkay

Hypothetically, most all Singer machines will fit in Singer cabinets (but not Kenmore cabinets). By that I mean that they will fit on the pins and in the holes. I learned recently that they will fit, but not always fold away. I had a 15-91 (old black Singer) in a cabinet I didn't like and a Singer 600 touch and Sew I was giving away. So, I switched a 600 to the Singer 15-91 cabinet and vice versa. The15-91 fit the cabinet just fine with no problems. The 600 fit the 15-91 cabinet, but wouldn't fold away. The machine was too tall to fold away.

I just went around and measured the machines and cabinets I could get to easily. The old black singers and my 301 are in cabinets that are 17 inches deep, with a hole of 8 1/2 inches, front to back. The cabinet originally for the 600 is 18 1/2 inches deep, with an 11 inch hole. I no longer have the 600 to measure it's height, so I can't compare it's size to the height of a 503, which is about 8 1/2 tall, as is the 15-91 and the 301. The 503 is wrapped and in storage, so I could only get an approximate height, but it appears to be the same as the other pre-touch and sew models.

I hope this helps. After all this measuring, I think the 503 will fit in any Singer cabinet from the 1940's forward.

bkay

edit: The old black Singers have have a spacer that has to be removed to fit a newer machine, but it's easy to remove. Just turn the cabinet upside down on a table (with a pad to protect the finish) and unscrew that spacer.