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:
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:
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.
The Smell of Molten Projects in the Morning 
Had once a fitter’s vise. There was a “bubble” in the jaw construction. Obviously they don’t X-ray check these things.
Magnafluxing? We don’ need no steenkin’ Magnaflux!
I buy Harbor Freight not because I like it, but because I’m convinced that everyone is selling the same cheap plastic junk, and everyone else just charges more.
When you set up to do the CNC machining I’d be really interested in hearing the workflow/programs you use. I’m doing all my stuff purely through calculating and writing a C program to generate that, and I’d love to hear other options.
Based on an admittedly small sample, I have direct evidence that you’re absolutely right. HF sells bottom dollar crap for bottom dollar, which is at least a straightforward and honest business model.
It used to be that a company’s Brand Name stood for their commitment to value, but nowadays the names have no connection to the original companies or their products: the names are bought and sold based on historic value & reputation. That can’t possibly last for long after the new owners sell junk that doesn’t live up to the name’s reputation, but I suppose business practices now consist entirely of entirely of short-term local optimization.
Something is terribly wrong…
Despite knowing that ABS will fail miserably, I think I’ll 3D-print a prototype to make sure I get all the curves right. It’ll be the usual hand-coded OpenSCAD model, with an eye to converting the eventual coordinates & curves to EMC2’s dialect of G-Code for the Sherline. I think I can fixture it with some decorative holes along the midline…
In buying bike tubes, I’ve found that Continentals (while not made in Germany anymore) are made in Taiwan, and seem to do better for me than ones that are *not* made in Taiwan, insofar as not failing from mystery tears or stem ripouts.
I suppose at some point I should learn OpenSCAD.
It seems my mean-time-between-orders is longer than their mean-time-to-new-vendor, no matter what I’m buying: US to Japan to Taiwan to China to India to Pakistan to … maybe, someday, the US again?
After you understand it’s not C, you’ll do fine.
Really, at the price point that these clamps were selling at around here and on eBay, these could never have been manufactured for performance or reliability. You really must move up to at least Irwin clamps if you want something that will begin to approach useability, and then consider Jorgensen if you want something that may even exceed your requirements for a one-handed ratcheting clamp.
Yup, two bucks at Harbor Freight doesn’t buy you much reliability. That said, HF recently changed the handle design & material; perhaps they got tired of replacing every cheap clamp they sold.
Amusing story: I brought the repaired clamp along to my 3D Printing Show-n-Tell session for Squidwrench and had to print a handle for someone who said “Hey, I have a broken clamp just like that!”
I do have a pair of larger Irwin clamps that work reasonably well and some bigger (and less marginal) HF clamps. One can never have too many clamps, but my toy budget won’t cover enough Jorgensens… [grin]