Clamp Jaw - Repair/Replace

This is a repair of an old Harbor Freight ratchet clamp (which I have repaired twice before!). As can be seen in the photos, one of the plastic jaws broke (again), so I decided to try replacing the entire jaw.

Unlike some other similar replacement jaw models I have seen posted, by design allows for the jaw to be printed on its side, aligning the filament deposition for maximum strength. I based my model on the original clamp, with some changes to for ease of printing, as well as making it thicker to strengthen the jaw. I used PETG for the replacement jaw; initial tests show that the new jaw is strong enough for the job, but long term use will be needed to confirm this.

Additional required parts : 1/2" X 1" pan head or round head screw with hex nut. The original screw cannot be re-used because I have increased the jaw width to increase strength.

This clamp is no longer sold by Harbor Freight (they now have a new design), but no doubt there are a lot of old clamps still out there which might benefit from this (or similar clamps which are still being sold).

Assembly and Use

Before putting the jaw on the clamp bar, you must remove the sacrificial supports in the screw holes (both sides), and in the opening for the bar. I used a razor knife to remove the hole supports.  The supports in the bar opening can be removed with needle-nosed pliers.

With all of the supports removed, placed the jaw on the end of the bar, insert the screw, and tighten onto the nut.

Print Instructions

Print in PETG using the 3mf files provided, otherwise :

• 0.2mm layer height

• 14 perimeters

• 15% rectilinear infill

• supports - use painted on supports under the narrow end of the jaw (the shoe for the clamp pad)

CAD

The OnShape 3D CAD files for this are here :

https://cad.onshape.com/documents/7cdabaeee123e6698c390a79/w/736872d96e67e8bc635c904d/e/2ffc5f5fd80f502a8d33890c?renderMode=0&uiState=69ec05aedb3be5ce86c84037