Review on Effortlessly Install Handrails With Zipbolt 40.260 Railbolt Drill Guide: Includes 1/4 In, 3/8 In And 1 In Spade Bit For Staircases by Devin Jirsa

Bits seem poor quality, expect to get better ones if you're working with hardwood. They cut poorly in red oak and one snapped off in the hole. Also on angled cuts, the guide seems to put the big bottom hole too close to the end of the railing. Was able to get it to fit by drilling the end hole farther, past/through the bottom hole, and starting the tensioner before the railing came up against the end newel and the tip of the bolt was still accessible. This set got the job done, but unless you're doing the most basic of install don't expect it to go nearly as smooth as Zipbolt would lead you to believe.