I have the facilities (my former high school), the distributor (that my shop teacher recommended), source of Kevlar as the connecting fabric, and all for around $200. That can/will be problematic when I convert it to the 1/16in - 1/8in sheet steel. I had to cut my helmet in 7 places to make it fit. My head is 23.5in head around the fore head (ears not included) but there is plenty of room once it is on though.
One problem is that, bare with me now,when I pull it on over my head it is to tight. So it has been a while but I have finally made my prototype N7 breather helmet HD after 40+ hours of work.
