<https://www.lumberjocks.com/threads/good-for-most-clamping-not-all.324137/>
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"BORA - Parallel Clamps (Rating: 3)\n\nI've had these BORA parallel clamps for a year or so and wanted to jot down some opinions of them for everyone.  Generally I like them.  They are smooth to operate, intuitive (lift up on the handle to release and move the head), can apply a huge amount of clamping pressure, I like the little elevation foot thing on the far end of the clamp, the spacers are nice, build quality is good.  Really, for regular clamping I don't have any complaints and they have been great.\n\nHowever, let's talk about that non-square end.  If you're unfamiliar, maybe check out this video here:    The idea is by setting the clamp end to a slightly acute (NON-90 DEGREE) angle, when tightened, both ends of the clamp will true up under pressure and provide even clamping pressure across the whole face of the clamp head.  I will say - they function as intended.  They do true-up to parallel when tightened, and they do appear to apply good pressure across all of both faces.  But, despite that it introduces a couple other issues I need to mention:\n\nIssue #1 - Because of the slightly acute angle of the far end of the clamp, it appears to apply a small amount of shearing force upwards from the clamp when tightened.  If you are clamping a mortise and tenon joint, there are no worries at all and they're awesome.  If you're clamping something like a shelf in an open dado or something more delicate that needs precise placement, the pieces can move on you no matter how much coaxing you provide while tightening down.  I even applied a couple other clamps to hold a piece in place once, and the shear force was enough to overcome that and still shift my pieces slightly.  On this glue-up I got about 1/32 movement.  It can be sanded out, but it's just a bit frustrating.\n\n\n\n\n\nFor detailed work, I would prefer a parallel clamp with a 90-degree head so I can put my pieces exactly where they should go during glue-up.\n\nIssue #2 - These clamps are marketed as being able to be spreaders as well as clamps.  Simply reverse the sliding part and now use the outside of the fixed side as a spreader.  They will in fact do that.  However, because the fixed end is FIRMLY mounted at an acute angle (becomes obtuse when using the outside), and the moving head changes angles to true-it up when tightened, when you flip around the slider, it becomes further out-of parallel when tightened.  It \"corrects\" the wrong way and the clamp heads are NOT parallel.  Even on something big, I would not use these clamps as spreaders unless you use 2 of them to cancel out the non-parallel effect.\n\n\n\nIn conclusion, I am glad I bought these clamps.  I got the 50\" version and it saved a lot of money.  On bigger pieces like tables and cabinets they will work great.  However, I found myself using them for smaller detailed work too (they can just lay on the table and length doesnt really matter unless they are too short), and for this kind of thing the angled head just causes more problems than it fixes.  I will be buying a different brand for my future smaller parallel clamps.\n\nHope this helps someone.  Any questions, ask away!"
<https://www.lumberjocks.com/threads/good-for-most-clamping-not-all.324137/>