| Hi, Everybody, Since I recently had occasion to maintain the spring-loaded bearings on the inner ends of shaft lift arms (the arms that rise up above the castle when the shafts are raised - the bearings in question are in the middle of the loom), I am recording the problems and the solutions here for my sake as well as for anyone else who may have such problems in the future. I first noticed the problem toward the end of a 20 yard cotton shirting run. There was a new squeek/squeal as the shafts went up or down. We had a dreadful time trying to pinpoint where it came from. I sprayed oil in all the suspected places, but nothing changed. Eventually we located the source in the spring loaded bearings on the lift arms. It turned out that after eight or so years of weaving, the nylon bushings (there are two in each left/West lift-arm) that the upper and lower springs ride on, had worn through and the metal spring wire was rubbing against and squeeking on the screws that hold the bushings. This yields preventive maintenance (PM) tip (30-1): PM tip 30-1: Check the bushings for wear. If any wear is evident, loosen the phillips head screws that hold the bushings and rotate the bushing a quarter turn so that a new area of the bushing is exposed to the friction of the springs. At the same time, I also noticed that some of the shafts had a tendency to float up when they should have stayed down. I found the source of the problem as I was loosening the springs to rotate the nylon bushings. The springs will, over time, fatigue. In particular, the lower spring tends to fatigue right where it goes through the nylon tensioning cylinder (the one with the knurled brass screw on the top). If the bottom spring is not straight, it cannot provide enough tension to hold the shaft down. PM tip 30-2: Check both the upper and lower springs on the shaft lift arms to make sure that they are straight, particularly where they go through the tension block. Make sure that the brass tensioning screw is not overely tight - see below. Remove all pressure from the springs by turning the brass screw counterclockwise. Remove the bottom spring (by removing the two nuts that hold it onto the bracket) and twist the threaded part between your fingers to make sure it is straight. If it is not, straighten it with gentle pressure. (Two of them were so fatigued that they broke while I was doing this and had to be replaced.) Check also to make sure that there is no twist in the spring - the various jogs on the spring should all line up. Replace the spring by running one nut all the way to the end of the threaded portion (after it has been pushed through the tension block) and barely starting the other nut onto the end of the spring. Now lower the shaft ***all the way down*** and by looking up from below, make sure that the hook at the end of the spring is sitting exactly on the lower nylon bushing. Tighten the two nuts to secure the spring in that position. Note that the brass screw is still up, exerting no force on the springs. After the nuts are tight, try raising the shaft by pulling up on the brass screw. It should come up easily. Now tighten the brass screw and keep trying to raise the shaft from the full down position. As soon as the screw applies some tension to the springs, some resistance will be felt to raising the shaft (assuming the lower spring has been correctly positioned). Tighten the brass screw just enough to get good resistance to raising the shaft and you are done. Cheers and good weaving, Tom. |