This device allows you to string an elastic cord through the hole and tighten it by 90 degree rotations. I'm still waiting on my ToM to ship, so I don't know how well this will print or whether or not the clearances will work. I placed the holes for #8 ANSI bolts (I think), but they shouldn't be hard to enlarge.edit: Rotated the models so they sat flat on the right axis, replicator g was surprisingly good at this.The string must be mounted so that it pulls the tensioner down a little bit, other wise it will lift up.