How to Bend Bay Window Corner Posts on a Tapco Brake 

February 21, 2023


How to bend bay window corner posts on a Tapco brake 

One of the problems seen on siding jobs is when siding installers try to stretch a 22-degree or 45-degree vinyl siding corner around a bay window post.

How to bend a corner post for a bay window

  • Starting on the finish side of the metal, bend a 90-degree fold, leaving a 2-inch leg as a nailing flange
  • Flip the workpiece and band a hem to form a siding pocket with a nailing flange
  • Extend out from the first bend about an inch and bend another 90-degree fold, to begin the opposite siding pocket, moving in reverse order from the first
  • Flip the workpiece, add the siding pocket hem
  • Tweak each siding pocket about 22-degrees to yield a siding-to-siding 45-degree corner post

Don't try this on a competitor's brake because you will be disappointed in the fact that you can't bend as close to the post as you can on a Tapco brake.


—This video is from Tapco Tools, one of ProTradeCraft's advertisers. Serving professional siding applicators since 1961, Tapco brakes and accessories bring measuring, mobility, decorative designs, and strengthening ribs to fascia, window trims, frieze boards, porch posts, and beams. See all of Tapco's content here.