Boring big or odd-size holes is easy: All you need is a template of the hole shape, a forstner bit to rough the shape and hog out the majority of the material, and a flush trim router bit to clean up the shape.
2x Matched Tongue Groove Router Bit Set 1/4" Shank Woodworking Tool Chisel Cutte
Flush Trim Router Bit Top + Bottom Bearing 1" H X 1/4'' Shank Wood DIY Home Tool
1pcs 8mm Shank wood router bit Straight end mill trimmer cleaning flush trim corner round cove box bits tools Milling Cutter
Rockler Piloted Flush Trim Router Bits - 1/4" Shank
Mission Lamp Built with the Rockler Piloted Flush Trim Router Bits - 1/4" Shank