my shiftknob came with a bolt, but it didn't hold up the shift boot. So what i did is found an old tupperware jar, cut out some circular designs and cut holes in the middle (kinda like washers, but a little bit smaller) and just put those on the bar. They slid down to a point below where the bar gets wider and they held up the shift boot.

Just something ghetto rigged, but it works until i get another shift boot