If you do not have cauls with you in the field when replacing a key bushing (either front or balance), here is an easy and effective method to keep pressure on the bushing cloth until the glue sets. Simply insert two flat screwdriver blades pressed together into the mortise deep enough to make secure contact and hold the new bushings tightly in place. (Use combination handle blades, without the handle). Leave the blades in position until the glue is dry.