This Instructable makes a small wooden clamp which uses a rubber band as a spring to hold the clamp closed.
Its not powerful. You can buy stronger ones for a dollar at Harbor Freight.
But, you can make one of these using a minimum of material and time.
It will be as strong as the rubber band you use.
* 6" X 6" piece of 1/8" Baltic Birch
* About 2" of 1/8" Bamboo skewer
* Rubber band
* Wood glue.
The Corel File cuts a 6 X 6 panel which has small (0.020) tabs in the cut lines that hold the pieces in place until they are poked out. While the pieces are held in place the panel can be sanded and painted (if you want).
One handle is made with three panels; two outer panels and a spacer panel (without a pivot hole). The outer panels for this side are marked with concentric circles around one of the pin holes.
The other handle has five panels, two outer and a center panel with a pivot and two spacer panels without a pivot.
Install pins that match the thickness of the handle. I only use a dot of glue at the pin site for each panel. It doesn't take much to hold the handles together.`
After the handles are assembled, assemble the individual swivel pads with their stand-offs.
You should be very conservative with the glue when attaching the stand-offs to the pads. If too much glue is used, it will may reach the swivel and lock the pad to the handle.
Its probably a good idea to pin the swivel pads into the handle while attaching the pad.
Once the swivel pads are mounted to the handles, the Central pivot can be pinned
The rubber band is stretched and crossed as shown in the picture.
I used a little wax on the pivot and swivel pads to smooth the operation.