I know this is a vague question, but while I was looking around on flooring sites, I found a wood filler designed for floors that claims it expands and contracts at the same rate as the wood. They had it in a trowel on product, and something runnier that you pour on and spread out.

I want to use it to fill the holes from the face nailer, and a couple of my boards didn't run through the mill properly and there is a small gap at the top because the tongue bottomed out in the groove before the tops touched. It's only a couple of places, not very wide, and maybe about 4-6 inches long.

I've read other places that some people don't fill wood floors because over time the filler works its way out. But this product claimed that wouldn't happen.

Not sure I buy into the expand/contracting thing with the filler, though it is possible to some degree, I suppose. We use Woodwise filler on all our floors. If your floor is new the filler should grab very well to the wood and not crack out under normal conditions. I do not use much filler on the sides of the boards when refinishing if the gaps are large. I feel that the existing finish has sealed the pores along the edges which does not let the filler bond to the wood.

FWIW, I have a very high-end cabinet guy and another trim guy who routnely ask me to get them gallons of Woodwise from my distributor because they too find it works so well. The key with fillers is to find one you are comfortable with that does not shrink much when it dries yet sands easily.

try home depot we used pro finisher white oak wood filler for floors it stains easy and sands easy its a water based formula works great. for small cracks and nail holes.