The Singer 500A Slant-O-Matic is sometimes referred to as the "Rocketeer" due  to its space-age styling. After the Singer Featherweight, this machine seems to  have the greatest following according to a Singer dealer we were talking  with.
The wavy pattern on the red and black quilt fabric banner above was sewn  using this Singer 500.
The needle is slanted bringing it closer to the user for better visibility.  There were arguments that the slant provides better penetration, but we wonder  about that since it seems farther through fabric at an angle than straight  through it. We have seen one sew through eight layers of denim and some claim  they can be used to sew canvas, etc.
When it comes to a vintage all-metal machine that is the most versatile using  built-in capability, this is our best one. By varying the two controls on the  top-center of the machine, a wide variety of stitch patterns emerge. Also, cams  or special disks can be purchased which increases the number and variety of  stitch patterns.
Some folks claim this is the last of the good metal machines. After making  these machines, the industry began using space-age plastics for some parts,  however, the change effects the way the machine sounds and feels. There is no  question that the newer machines have more capability such as drawing graphics,  stopping the needle at the desired point, ease of making buttonholes, etc.  Still, for those of us who like all things mechanical, we prefer heavy  metal.
The 500A Slant-O-Matic feature moves the needle over 1-inch closer to the  operator. The average bed is 7 inches wide and the needles are usually centered.  On the Slant-O-Matic, the needle is less than 2-1/2 inches from the edge of the  bed. This is a significant difference for some of us old people with failing  vision.