Intro: Panic Bar Door Repair
The photo shows the 40 year old panic bar door hardware on our church doors. We had a problem that left us wondering for a bit if we would need to buy new door hardware for $600, but solved the problem inexpensively.
Step 1: How It Is Supposed to Work
Sunday mornings we "lock" this door open by pushing the bar toward the door and turning a hex key clockwise in the hole shown. That causes the knuckle in the panic bar to remain pulled inward in the direction of the door, as you can see just above my hand. Someone had turned the hex key counterclockwise. When the door did not "unlock," he got a big pliers and began to force the hex key. The internal parts were bound so tightly that he cracked a part inside. This Instructable will show how to make a replacement part.
The first step was to remove the cover over the mechanism. You can see two screws on top of the cover. There are two more on the bottom of the cover, too.
Step 2: The Mechanism and How It Works
This view looks down on the mechanism from above. The cover has been removed from the mechanism. The two upper screwholes are visible on the casting. The black square surrounds the hole where the hex key is inserted to lock and unlock the panic bar mechanism. The green outline is a special 5/16" x 18 thd. setscrew with a dome end. When the panic bar is pushed toward the door, the portion of the bar at the mechanism pivots around the shaft shown by the red circle in the direction of the red arrow (counterclockwise). The domed head of the setscrew comes to align directly opposite of the pale blue line, which represents a flat spot on the frame of the mechanism where the domed head comes to rest as the setscrew is turned clockwise to extend in length. The yellow lines represent a heavy spring which makes it difficult to insert the shaft encircled in red if the mechanism is disassembled. Getting it all back together again is a two man job. One pushes against the spring while the other inserts the shaft. Even then it is not easy.
Step 3: The Setscrew With a Dome Head
The photo shows the replacement screw I made. The two green lines represent the cracks in the original screw caused by turning the hex key in the wrong direction with extra leverage provided by a very large locking pliers. The yellow lines, arrows, and numerals give the sizes in inches.
Step 4: Materials Used
The photo shows a 5/16 inch x 18 thread per inch setscrew 1 1/4 inches long. This is a standard item from the local hardware store and cost just a little more than half-of-a-dollar. In order to make clear that it has a hex-shaped socket on one end, I inserted a hex key for the photo.
In addition I used a common 5/16 x 18 hex nut.
Step 5: Grind a Slope
The hex nut will be welded to the setscrew so the domed end can be formed. It is necessary that there be an opening for a weld to be made. I ground the blunt end (not the end with the hex socket) of the setscrew off at about a 45 degree angle.
Step 6: Add the Nut
Grinding may have disturbed the threads enough to make threading a nut onto the setscrew a challenge. Add the nut from the hex socket end of the setscrew. The portion of the setscrew held by my fingers from its end at the left of the photo to the left side of the nut should be exactly 1 inch. Notice the cavity inside the nut formed by grinding a slope on the end of the setscrew.
Step 7: Weld
I used a wire feed welder to get into the cavity and fill it with weld material, fusing the nut to the setscrew. (first photo) The second photo shows the end of the setscrew after the nut has been welded to it. At 1 1/4 inches in length the setscrew is a little long and will need to be ground down to 1 3/16 inches in length. It is no problem that the weld material did not fill the entire area inside the nut.
Step 8: Grind
I chucked the setscrew in an electric drill and spun it while holding it lightly against a spinning grinding wheel. This takes the corners off of the hex nut and makes it nearly round at just about 1/2 inch in diameter. See the second photo. I began grinding to length and in a dome shape. The chuck on the drill will loosen frequently. Stop and check it regularly. I wrapped the threads in a little masking tape to protect them, but, the remnants of the tape were difficult to remove from the threads. If you are careful, you will not do much damage to the threads with the drill chuck.
Step 9: Finished Part
This is the finished part. Right now the original cracked setscrew is still working, but the day may come when the small piece between the cracks breaks loose. When we did have the mechanism apart, someone chased the threads to remove rough spots over the cracks. Now we have a backup part we can install quickly and easily. We had searched the internet for a replacement part, but we actually could not even find a manufacturer's name or a model number on our hardware anyplace. I must admit we have not tried our replacement part yet because the reassembly of the mechanism is difficult and an unpleasant task. But, what the part needs to do does not require a lot of precision, either. So, we are quite confident.
It is hoped this Instructable will inspire someone with a panic door hardware problem to consider making a part, even if it is not the same problem or the same hardware. Making a part is much more economical than replacing hardware on even one door. But, that almost certainly would not match the old hardware, and aesthetics would require replacing the hardware on at least two doors. This little fix cost less that a dollar, plus an hour or so of time.