Singer 7-33 has two issues that come up if you've seen enough of these machines.
The take up lever hinge screw if it becomes loose, can break the casting or threads. This is why Consew and Seiko have a removable take up lever bracket if this happens. On a Singer, it's a much bigger deal.
Now, when the Singer 7-33 breaks at the beak, it's just about done. I've seen brazing that has held up over time on some repairs that come in that I guess hold up, but it's not a machine I would buy to rebuild.
Once in a while someone will over tighten the race saddle that has a single clamp screw through the casting of the bed. This is a problem too, but only if someone decides to over tighten this.
Some of these were from the 1930s and offered as a extra heavy duty canvas machine with a maximum presser foot lift of 9/16 inch. Most are doing much more than that now with very heavy presser foot pressure.