Q: A contractor told me that an orbital sander will leave swirls in a 125 year old wide plank pine floor, and that the floor needed to be hand sanded.
Is this in your experience?
A: By orbital sander, do you mean one that takes 4X8″ sanding sheets? Any machine can leave marks, but is not necessarily so. You have to make sure the abrasive is attached snugly and if you pick up resin on the abrasive, change it. Make sure to apply even pressure (not more on the rear or front of the machine, but even). Worst case: if there are some squiggles, you can always rub them out by hand if need be. This is not a forgone conclusion.