Back in their day, and maybe even today, Marples, Craftsman, Disston, all made fine tools. But if the age you state is correct, 80s, 70s, 60s, then it is unlikely the tools are made from the current modern high speed steels used in all the high end turning tools today. They were just regular carbon steel. As others stated, you will get plenty of sharpening experience using these tools. They will function just as well as newer upper end tools. Just more sharpening. keep them and use them. Doubt the tools have any collector or used value.