Michael Kellough said:
Obtuse is always bad.
Acute is okay when the bar is longer than 24".
The longer the bar the more it bends so even more acute is okay.
I know what you mean, but it depends on if the bar will flex. When clamping cabinets together and the bar rests on the box, no flex can occur. Also, these Bessey bars do not flex much. So I say Acute is sometimes worse than obtuse when it racks the parts inward. The only way to combat this Acute problem is to back off the bar from the parts so only the outer 1" of the clamp jaws are in contact.
I just glued up a set of Euro style cabinets and the Acute KRE clamps from Home Depot pressed in the sides so much, they were bowed in. The result was a gap on the outer edge of the boxes at the joints.
If I could post pictures, I would show you how bad these New China made KREs are. I'm pretty much done with Bessey, as their quality is downhill.
Bessey VP of Marketing just rejected my warrantee claim...even after I provided clear pictures of the Problems. This group buys Festool for quality German engineering. Bessey is no longer that. Bessey reps told me that bars are made in Gernany, but the rest of the parts are made in India and/or China. All are assembled in China. Below are some picture to illustrate the problems with overly acute angles in a long fixed jaw.
----------------------------
[attachimg=2]
The above image shows the effect of the Acute angle on the fix jaw under clamping pressure. The cabinet being glued shows a noticeable uneven glue joint. You can see an air gap above as well indicating the acute angle jaw is never zeroed out to square.
[attachimg=3]
The above image is another example of the same effect when an overly acute jaw angle does not parallel the work pieces. Note this would not be such a problem if gluing up 4/4 panels. However effects are magnified with full contact of the long jaws. The result is unacceptable.
The next 3 pictures show the acute angle of the fixed jaw at rest. I did not measure the angle of degrees, but you can see the air gap is greater than 3/32", but less than 1/8". This gap was consistent across 4 clamps purchased at Home Depot the week of 14 March 2022. All came from China.
[attachimg=7]
[attachimg=8]
[attachimg=9]
This last picture below shows the old KR clamps manufactured in Germany around the 2012 time frame. Note the square is NOT under pressure from the movable jaw...just resting on it. The evidence shows a near perfectly square fix jaw on the old KR version.
[attachimg=10]