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Archive for November 4th, 2011

Harbor Freight Bar Clamp Failure

The squeeze handle that tightens the bar clamp cracked exactly where you’d expect: directly across the pivot hole where the miracle engineering plastic thins down to a precarious ridge. The end of the handle is still inside the clamp:

Bar clamp with broken handle

Bar clamp with broken handle

Nothing bonds that plastic, so, in the nature of a quick fix, I cut a steel strap to wrap around the perimeter of the broken section and epoxied the whole mess together:

Reinforced bar clamp handle

Reinforced bar clamp handle

That lasted for exactly 2.5 squeezes and then pulled apart; the epoxy doesn’t really have anything to grab.

ABS isn’t a good substitute for engineering plastic, so this will require a bit of CNC work on the Sherline. I’ll probably carve the first one from polycarbonate, just because I have a sheet of the right thickness, but it really cries out for aluminum, doesn’t it?

Why CNC? Well, I’m going to make a handful of handles and get proactive on the other clamps.

My other bar clamps have much heavier sections in that area, so perhaps the folks supplying Harbor Freight could take a hint? Yeah, but the clamp was cheap, which always conflicts with good. On the other paw, I’ve seen exactly this same clamp priced at not cheap elsewhere.

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