John Made Ring Roller
The ring roller is used to form strips of steel or pipe or rectangular or square section into curves or circles. This home made version will handle up to 1/2 inch thick and 4″ wide. (12.7×100 mm). It is powered by a 1/2 HP electric motor, geared down 1:60. The chain drives the bottom 2 rollers. The top roller is a cluster of old ball bearings. The top roller is adjustable for height, with 2 spring loaded 16mm nuts. The case is 16mm plate, bolted together with 10mm cap screws, so it is reasonably heavy duty.
I added the infeed and outfeed rollers as an afterthought, to avoid any possibility of the work twisting in the machine.
The video shows making a semi circle of 25×25 SHS, in a diameter of approx. 1.5 meters, but I have made circles as small as 150mm in 12×40 mm mild steel.
The Roller is bolted to a steel bench and is easily removed when not in use. The motor stays attached permanently.