"tom" wrote in message
We have just finished building a beautiful open staircase using
straight-grain, clear 3x12 fir planks. We held the staircase together
with lag bolts countersunk in 3/4" holes. I am having a hard time
finding any wood filler that comes even remotely close to the color of
fir. Any ideas on where to find such a product?

Have you tried a mixing up a little white carpenter's glue and some sawdust
from the fir planks?