I have had to plane off an amount on the latch side of an old (80 yr or so) interior door. Now i need to deepen the mortise the old style latch fits into. Kind of at a loss as to what to use to reach down in there probably close to 3" to take another 1/4" out. The mortise is approx
5/8x4xhowever deep. Any ideas short of drilling and digging with a bent chisel?thanks!