For my non-Battletech ships, my current preference is to use brass tubing. It's a bit complex, but a bit of brass rod drilled directly into the ship and base, square brass tubing over the rod, and a slightly larger square tube over the base only leaves you with a very strong steam that you can make any length you want, and the ship easily slides right off the base when in storage or transport, while staying secure on the base during play or display.