On 1/18/2013 9:08 AM, Jim Ialeggio wrote: > Ron wrote: > > <For us, clamps aligning soundboard panels for assembly, and clamps for > holding key sets are crowned to maintain pressure in the middle. > > I've never had a curved clamping caul perform very well, and basically > gave up on them. They apply pressure in the middle at some point, but > pressure is uneven, unto zero along other intermediate points along the > clamp. The deflection under pressure never turns out to be a fair curve, > but one that dips and dives. Maybe within a 2ft length, but not @ 4ft > which is what I usually need them for. That's the big problem with them. If made from a material of uniform moe, and the crown is shaped appropriately and accurately, you can get good results. I rely on a pad to take up irregularities, which works well enough for my uses. Defining the curve is critical, but I'm not entirely sure how. Logically, a constant section uniformly loaded beam should describe about the right curve. > On my soundboard panel clamps, I have a set of 1 or 2 degree wedges I > use to align along the length of the clamp, if I see that I need them. > > I also now use spring loaded go-bars if I need intermediate convincing > in other wide glue-ups...but dont find I need them too often. Have you seen these? http://www.frontlineengineering.com.au/ Ron N
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