Hi John,
Welcome to this forum.
It is, in my book, definitely a keeper as you have a very solid drill press.
While my knowledge of electrical motors is limited to some basic troubleshooting it would be useful to know if your motor is tripping the breaker with no load on it (belt disconnected) or only with a load (belt connected)?
With that extra piece of information I would take it back to the repair shop and explain what is happening. Maybe they only bench tested it and your problem is running under load.
Do you have another piece of equipment with the same voltage and HP as your drill press one to verify that it is not your wiring circuit that is the culprit?
Also replacing the motor is pretty straight forward once you get over the intimidation phase of it.
There is another forum call Old wood Working Machines (
http://www.owwm.org/index.php) with a focus on old American arn as they like to call it and machines such as yours. Their forum is a little more rule oriented than this one so be sure to read over the OWWM Forum Rules prior to posting.
OWWM has a electrical sub-forum which would be a great resource for a drill press motor question such as yours. They may be able to help you understand what is causing the short as that is what it sounds like your problem is.
The below “900” series drill press publication is from The Vintage Machinery web site (
http://vintagemachinery.org/home.aspx) and another great resource for old American arn.
It looks like your drill press originally came with a 1/3 HP 1740 RPM motor which should be easy to find a new or used replacement for. All electrical motors have a frame size associated with them which will be located somewhere on your motors label which will also list the HP and RPM.
Electrical motors NEMA frame dimensions.
www.engineeringtoolbox.com
Hope the above is of some help.
Harry
PS - Just thought of something else. You might want to check your electrical cord to verify that it is not causing the short. Maybe it is very old and brittle with a possibility of a bare wire only touching when in a certain position.