What's up with the different kinds of bar clamps?

Hey all,

Today, I got my first "useful" (i.e., non-calibration) print out of my prusa mendel. It was a bar clamp which I got off the Prusaj github. It looks mostly like this:
[www.terabyts.com]

The version I bought, however, looks like the one on the Wiki (http://reprap.org/wiki/Filem-bar-clamp.jpg). One could "stand the U upside down" because it doesn't have the angled edges. I think my not-entirely-calibrated printer might do a better job with it.

What's the deal with the two different bar clamps? And why can't I find STL files for the second type? Any help tracking it down would be appreciated.

Brad

I suspect the change is just to save a (tiny) amount of plastic, and maybe to make it look a bit better. Here's the old stl:

[www.dropbox.com]

(To get it I looked throuh the prusaj github to the prusa v1 code, and generated it with openscad. Yes I'm bored.)

Hi Brad,
The best of the bar clamps out there, in my view, is this one: [www.thingiverse.com] by Tirffid_hunter. There are improvements over the Prusa one, and the original full u-shaped one. The key fine-tuning is hole positions which allow the two rods being clamped to sit together. This is very good if you want your y-smooth rods to sit on the horizontal threaded rods. The older 'original' design, or even the Prusa one (from his Guithub location) doesn't do this. The crossing rods don't touch, there's a gap.

The second improvement with Triffid_hunters design is the U-shape is slightly open when printed, so only moves to a true U shape when clamped, performing an excellent clamping action, better than the original U.

I think the wedge cuts are just a style thing,

I'd recommend the triffid_hunter clamp, based on my experience. Print them both and compare the clamping action and you'll see.

Regards,
NumberSix

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[numbersixreprap.blogspot.com]

Thanks Misters Glanville and Six. I appreciate the community support.

What's the benefit of getting the Y smooth rods touching the threaded rod with the triffid hunter clamp?

If the y-rods are resting on the horizontal threaded rods then you have a good level starting point for your bed to rest on. It's better than having them raised off at four points and the height dependent on print quality of the clamps. (It's a minor point really though in the scale of what impacts print quality). You need the rods to be nice and level and lots of things factors in.

The way this clamp is splayed when printed and then closes in to clamp on the rod is better than the original design also. It's not the end of the world which one you have or use, but if you are printing new ones I'd recommend the triffid_hunter design.

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[numbersixreprap.blogspot.com]