You don't need to have the grooves every 1/4". Just run it throught the saw
blade every 1" or so. Bats aren't particular and will surely find any
groove to get a toe-hold on. Heck, I've build them using luan in the back
and made utility knive cuts across the grain with firm pressure. They pay
their rent on time and eat a lot!!

"Toller" wrote in message
news
I am building some bat houses, and they need rough wood so the bats can
hold
on to it. It is suggested to run a series of 1/32" deep cuts with a saw,
going both ways, but that will take forever.

I was thinking of having the outside blade, a 1/4" spacer, a chipper, a
1/4"
spacer, and the other outside blade; so I am cutting three cuts at once.
It
will still be work, but only one third as much.

Any reason this will make the dado set explode, or anything else
undesirable.
Any better suggestions for roughing up wood?