Costume History, Menswear Hand Drawn Collar patterns of Early 20th Century Detachable Collars Pt2: Triangle “Plaza” Club Collar with Lock front January 27, 2019 tara@costumes.org So, continuing with the drawings I made back c.1978-80 of my collar collection, here is another example. Another club collar, the Triangle “Plaza” Collar. Triangle Plaza CollarTriangle Plaza CollarTriangle Plaza CollarTriangle Plaza CollarTriangle Plaza Collar Triangle “Plaza” Lock Front Club Collar Spread the images so that the front buttonholes are 1/4″ more than your neck measurement then connect the lines and move the back button hole equidistant from the two front ones. Add seam allowances and sew together normally.