I bought a pin pusher (see pic), but I think the internal diameter is too big for the pins supplied in the kit. If you enjoy building ship models that are historically accurate as well as beautiful, then The Nautical Research Guild (NRG) is just right for you. I've acquired a few pin pushers of various sizes over the years at garage sales and the like and I occasionally use one, but a more versatile and more easily controlled solution, as Jaager sagely notes, is a pin insertion plier. The Guild is a non-profit educational organization whose mission is to “Advance Ship Modeling Through Research”. We provide support to our members in their efforts to raise the quality of their model ships. Yes, you've correctly identified your problem. Pin, or brad, "pushers" are made in a variety of sizes to fit the brads and pins they are intended to push.