Heh. I thought someone might have had that reaction to the name. From the Houston Press:
Power Tools A long-gone cousin of Numbers, Power Tools is still a sacred name (not to mention a powerful memory) among Houston's industrial/goth/EBM crowd, with the downtown subterranean space now occupied by hip-hop/EDM-heavy Kryptonite. Like a few of its kin, Power Tools is practically un-Google-able, but one flyer we did find (again via Ozone City Outrage) offers a powerful whiff: Butthole Surfers. Mid-August. All ages. CHRIS GRAY
But to answer your question, not a gay bar.