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Top Shops: Convertible doors

Building a shop is often routine. Pick what you need, hire a contractor, pay the bill. For Fred Butuk, that's not quite the case.

Butuk was an engineering technologist between 1978 and 2005. His name is on about a dozen patents for air seeding and no-till systems.

In 1990, Butuk and his brother, John, picked out a shop and hired a contractor to build it on their farm near Insinger, Saskatchewan. They chose an all-steel building with a 26-foot-wide opening for a future door.

Filling that 26-foot hole became an issue for the brothers. Opening it in the winter would waste huge amounts of heat.

So Fred Butuk put his inventor's hat on and came up with a novel solution. Instead of installing one large overhead door in the 26-foot space, he innovated a movable post that allowed the use of two doors.

One door is 10 feet wide while the other is 16 feet. The post dividing the two doors can be readily moved to the side after both doors are open. Doing so provides a full 26-foot-wide opening. Or "we can open just the 10-foot-wide door if we want to bring just the pickup in during the winter," he explains.

The movable post was made of 4x8-inch rectangular tubing. The bottom of that post is held in place with a 2-inch-diameter pin (see picture on the next page). That pin is pushed down into an anchor in the concrete drive using an air brake pot from a truck. Applying air to the pot causes the pin to raise and free the bottom of the post.

The top of the post will eventually ride on a trolley rail. It is currently being held in place with bolts. But Butuk is planning on using another air brake pot to raise the post after it has been freed up at its bottom. Once raised, the post will then be able to be pushed to the side while riding on the rail.

The doors that operate on either side of the post were custom built by the Butuks. They hired a steel supplier to cut the sheet metal (20-gauge galvanized steel for exterior panels) in 10- and 16-foot lengths. With a press, he bent the outside face panels to make four sides. He mounted spars inside these panels to keep them rigid.

Two layers of Styrofoam insulation are inside the exterior panel. Interior-facing panels were riveted to the exterior steel. The resulting doors, which are 14 feet high and 4 inches thick, are heavy duty, with the emphasis on heavy. For example, the 16-foot-wide door weighs as much as a commercially built 24-foot-wide door, or around 1,350 pounds. The 10-foot door weighs about 840 pounds.

Normal wound-up door springs weren't powerful enough to assist in lifting the door. And keeping the doors up and preventing them from crashing to the floor was a concern.

So Butuk fashioned a counterweight system to help lift the doors. He poured concrete into 2-foot-square steel frames to create the weights. Each panel in the doors required one such weight.

Each counterweight for the 16-foot-wide door was poured with concrete 6 inches deep. The weights for the 10-foot door received 4 inches of concrete. The resulting weight was just right to counterbalance the weight of each respective panel.

Spacing the counterweights in a steel tube truss required careful thought and basic math. Butuk determined each counterweight had to travel 17 inches to lift one panel by 24 inches. In addition, the lifting force had to transfer horizontally to the door and then downward to the sides of the door panels.

"A lot of thought went into the cable system to get that motion to the doors," he explains. "The counterweights don't travel as much as the door panels, so each one has to exert more force on the cable than the weight of the panel itself."

A sprocket and chain drive serve as a temporary mechanism to raise the counterweights in the truss stand. "The hand crank turned out to work quite good," Butuk reports. "But I will convert the cranks to electric motors in the future."

Building a shop is often routine. Pick what you need, hire a contractor, pay the bill. For Fred Butuk, that's not quite the case.

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