Plastic gun cartridge divider trays make excellent router bit holders. I use them both to store my bits and to keep similar bit styles or sets together. I find .45 caliber holders are perfect for storing 1/2″-shank bits; .38 caliber carriers are just right for 3/8″ shanks, and .22 caliber sizes work well for holding 1/4″ bits.
– Frank C. Manley
Broadview Heights, Ohio