Trotter Manufacturing, Inc. has manufactured valve spools since 1985 and is particularly experienced in machining tight tolerances in diameter and cylindricality. TMI routinely and consistently holds ± 0.00006″ – 0.00008″, putting us in an elite class. Our ability to provide rapid prototyped and sustained delivery performance make us reliable for your product needs. And our continuous improvement culture allows you to remain competitive in your marketplace.