Trimmer was received as a gift and squirrelled away for several years. Now decided to put it to use and have run into a problem. I see no way to capture the collets. The Collet Holder Assembly has nothing in it to capture (thread into) the collet. The body of the collet holder below the threads is an empty tube. What am I missing here? Was holding on RCBS's customer service line for over an hour and gave up. HELP - Frustrated and Confused.