Handheld Clamp

A one-handed spring clamp that prints as a single assembly. Squeeze the handles and the jaws open; let go and the C spring pulls them shut. The pads sit on swivels, so they lie flat on the work even when the jaws are open wide.

The clamp comes off the bed already assembled: two levers on a captive centre pin, a C spring held between them, and a swivel in each jaw. The two removable pads print beside it.

How it works

• Levers: both turn on one captive centre pin, and the handles cross over to work the jaws.
• C spring: a separate part. Each end narrows into a neck with a captive pin that sits in a socket on one lever. The sockets are shaped so the neck sits close to one side when the clamp is shut and has room to swing the other way as it opens.
• Two-leaf spring (optional): a thin lengthwise slit splits the spring into two leaves, joined at both ends with round relief holes at the slit ends. That makes the spring easier to squeeze and lowers the strain in the plastic.
• Swivel jaws: each jaw holds a captive swivel with a dovetail stem. The pad backs are notched so the pads can tilt with the swivel through its full travel.
• Grip ribs: the ribs run along the handles, beyond the spring slot.

Printing

• Print the clamp flat, as it sits in the model, in one go. The moving parts are separated by small gaps: 0.2 mm around the spring pivots and 0.1 mm at the centre pin and jaw swivels.
• Print the two pads separately, flat. They're already laid out beside the clamp.
• The default slit and pad fit assume a 0.4 mm nozzle. If the 0.3 mm spring slit fuses on your printer, widen it slightly.
• After printing, work the handles a few times to free the joints.

Fitting the pads

Slide each pad onto a swivel stem until it clicks. The dovetail is straight and the snap bump is at mid-height, so a pad goes on from either end and either way up. Fitting the pads pushes the jaws slightly apart, which gives the spring a little preload.

Useful settings