It looks like this Part has been superseded by LEGO Part 24505 Technic Gear 24 Tooth [New Style with Single Axle Hole][Type 2].
Click on a colored part below to see the Sets and MOCs that use part 3648a Technic Gear 24 Tooth [Old Style - Three axle holes] in that color. You can find an overview of all LEGO Colors here.
If a color is missing, it probably needs to be added to a Set Inventory.
This part has been used by MOCs in the following colors but not officially released.