A piece of wood is sawed, milled and sanded. The wood can then be lacquered or oiled. For example, in the renovation of old silver brushes, the wood must usually be precision manufactured by hand to fit exactly in the silver bracket.
Holes for the bundle of bristles is drilled by machine. The holes are small on the upper side of the brush and is widened, so that they are larger on the other side - where the bristles are. In a regular vegetable brush it's about 40 holes, a tailors brush have as many as 255 - all of which will be filled with material!
Now it's time to attach each individual bundle of bristles to the base of the brush. The finished wood, thread and material in the form of animal hair, vegetable fiber or synthetic material is put together.
The wire, usually a stainless steel wire, is pulled up in a loop through the narrowest end of the hole towards the wider end. It is done with the help of a hook that is attached to a ring around the finger.
Each individual bundle of bristles is placed in the wire loop and pulled into the larger hole - right into the ground. The bundle of bristles is picked by hand from the pack of material, or a machine is used that dispenses out the right amount of material.
When all the holes are filled with bristles the brush is cut and hackeled to get even and smooth. It is done with a cutting machine. Finished!