Tool needed to fit a new fore end.

These days i acquired a new wood set for my first No.4 MkI*: rifle didn't need any wood replacement but i chose to give him a gift because he's my best shooter. Now it's quit simple for me to cut the draws ( or re-fit them if i did it wrong). I have some problems obtaining full bearing around main screw and along receiver' rails. I use a small chisel , 3 mm large, but sometimes it removes too much wood . I'm not able to obtain a silky smooth, full bearing surface i saw on good fore end fitted from armoures.
So was there a secret tool to do the job , like a scraper?

Use the chisel as a scraper Bow. But DO NOT use the chisel as a chisel. Just use it to scrape the wood away until it sits level, smooth and even.