TROY, Mich. - MechanicalXchange welcomed four new contractor attendees to its 2009 roster. Brandt Engineering, The Unified Group, Hamel & McAlister, and Freitag-Weinhardt are all registered to be at the Xchange in Carefree, Ariz., Sept. 27-30. “They will make excellent additions to our Contractor Community,” said Chad Klein, event manager, MechanicalXchange.