I use rubber-faced wood clamps. Home Depot. A mechanical clamp can be set snug but ceases its clamping effect once set. Spring or other clamps may under some circumstances, because they apply continuous pressure, force too much glue/epoxy, etc out of the crack. This is not likely going to be a problem with Acraglas and the crack you mention, but might be, and just might be with certain wood glues. This is the procedure I use with bedding knife scales where forcing woo much bonding material out of the mating surfaces is a problem, or has been.