This was my first attempt at making a brush. The Knott i took out of a cheep brush bought at CVS and I had the antler laying around the house. after cutting and sanding the antler i drill out the center just deep enough for the Knott to fall in. Its about a 20mm Knott I think and my plan is to upgrade to a badger Knott when i can afford it. I bought some clear 5 min epoxy to glue the Knott in and also used it to seal the underside of the brush so it wont soak up water. I think it turned out OK for a first try.