Another method I use to keep the back lams in place is I have a 1/8" hole drill exacting in the center of the handle area in my form. I drill a 1/8'" hole through the center of all my back lams, after they have been glued together and then back glass, then I drill a 1/8' inch hole through into the center of my riser about a 1/2" or 3/4". I buy small bamboo cooking skewers and make pins out of them then cut them long enough to fit into the hole in the form, the lams, glass and into the riser. I put the pin in the form first then put my film over the form before glue up and punch a hole through the film with the pin, be careful to make the hole in the film as tiny as possible, then glue your stack and riser. Place your stack on the pin and clamp the riser into the form. the pin will hold the back glass, back lams and riser all together and keep them from slipping. I also use Kenny's spacer block on the belly side of the handle to keep the belly lams and glass in place. It helps keep everything in place, gives you peace of mind that the lams and glass will stay where you want them!! Don't ask me how I know!! I've learned a lot of helpful tips from the guys on this forum and have incorporated a lot of their suggestions into my own builds, it sure has made my life easier!!!