Male headphone jack adapter (for helmets/cosplay)

Been working on making a Kamen Rider helmet, but my original idea for joining the halves of the helmet together (purse clasps) didn't work.

I found this tutorial online:
http://www.geocities.jp/change_beetle2000/mask/mask.html
And decided to use headphone jacks instead (gotten from here: http://www.ebay.com/itm/231924019313?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT ). However, the male jackends wouldn't attach to the helmet on their own due to their shape, so I made this t