Here is a pretty simple way to make an Eva fore grip hood sleeve. Basically take an Eva Fighting butt with a tenon. Slide a cork borer with an ID the same size as the OD of the tenon over the and cut the EVA to a depth that fits the tube of the hidden thread hood. Cut off the tenon and remove the EVA by picking it out. Square off and smooth the inside of the the hole using a round grinding stone attached to a portable drill. The tenon acts as a guide to keep the hole centered. Works very well with EVA/Winn grips, cork, and foam core carbon fiber premade fighting butts. You can certainly turn your own cork or EVA on a mandrel and then slip on a 20 mm foam arbor onto the mandrel and use it as your centering guide for the cork borer.
