I've got an old squeaky hardwood floor with access to from below. I can feel the hardwood boards moving under my feet when they squeak so I just plan to drill up through the subfloor into the hardwood. Would drywall screws do the job? I noticed they're cheap, which is good since I will need a lot of them!
I prefer working from under the floor when possible. Although it is easier to screw loose flooring down from the top, it is often difficult to fill the holes and make the color and finish match. Using the top down method is a last resort, especially if you have a large area to secure. The Counter Snap screws mentioned in the previous answer are great devices, but commonly used to secure squeaky sub-floors under carpet. They will work on wood, but prefer a counter-sunk finish screw. With finish screws, you can control the counter sink depth and the head is about the same size as a finish nail.
Using blind screws from the bottom is a common way to attack your problem. The method of "pulling" the finish floor snug is important. I have used drywall screws many times with great success. You have to be very careful to calculate the thickness of the subfloor and finish hardwood, so the screw does not protrude through the floor. If in fact the subfloor is pine or soft wood, a drywall screw may be a bad choice as they can be aggressive and counter sink themselves too deep. Remember, the goal is to pull the finish floor down snug. This can be done by predrilling holes in the subfloor at the same or 1/32" larger than the diameter of the screws. That way, the screws are only threading into the finish floor, not the subfloor. When the screw head contacts the bottom of the subfloor, all force pulls the finish floor down to the subfloor. You can use a collet or a piece of tape on your drill bit to gauge the depth of your holes and not go into your finish flooring. Rather than a countersinking screw, like a drywall screw, use a #8 panhead screw sized to only penetrate the finish floor 1/2" (for 3/4" flooring). Just tighten the screws enough to make them snug, don't try to over-tighten them as that may cause them to strip out. Plan on using quite a few screws. I usually start by spacing them 8 to 10 inches apart. In stubborn areas where the squeak just wont go away, you may need to add a few more screws. Good Luck.
Drywall screws are for drywall any other use and the heads tends to snap off. Wood screws are what you are after. Also, be careful, if you have an old floor it is NOT 3/4 anymore because of shrinkage due to drying out and from resurfacing. Same for the sub floor, it is not 3/4 anymore especially since they are probably pine. I would not go up through the sub floor as driving a screw up into the finished floor will pull the sub floor to the finished floor. The correct way of doing this is to go through the finished floor from the top INTO a floor joist and fill the holes. But wait my floor will have holes in it and I don't want that... Well they sell special screw just for this type of repair operation, it has a special thread and shank after you screw down the floor you use a special tool to snap off the shank and it leaves a tiny hole in the floor that you fill. Sorry forgot the name of the screws. But the only correct way of doing this type of repair is to go from the top down an to hit a joist.
Just looked up the screw name, they are called Counter-Snap screws and the hole they leave is 1/8 of an inch.
If you sprinkle corn starch (Argo is one brand) or talcum powder over the floor and then sweep the floor the powder will get into any voids and act as a lubricant.
Don't vacuum the powder up, sweep the entire floor to allow the powder to fall into the voids. After a few days you can vacuum or mop the floors to remove any excess from the surface.
In my experience, this would be a bit of a fool's errand.
Most older houses with the type of floor construction that you describe have a lot of loose squeaky boards.
First you have to consider the large number of hardwood floor boards that you would have to secure.
Then as you said, the floor is maple which is very hard and tends to crack very easily if you do not pre-drill to the appropriate size and depth.
Then to you have to think about the fact that many of the squeaks could be coming from the interface of the sub-floor boards against the floor joists.
And to top it all off, if you manage to secure everything tightly enough to eliminate the squeaks, chances are the floor will no longer be able to expand and contract with changes in temperature and humidity as it once did, which could lead to buckling, cracking, or worse yet, more squeaks...
If you have a few particularly bad spots you may try to fix those, but I would just consider the squeaks some of the character of an older home.
