Solution
In polymer plain bearings, the organ-builder saw a replacement for the imprecise, work-intensive fabric bearings. These traditional bearings suffer greatly under the special installation conditions. While oak, hornbeam, and walnut are predominantly used in organ-building, and the material and bearings are constantly exposed to cold, moisture, and grime.
So
plain bearings made of iglidur J were used instead. The material features vibration dampening, resistance to chemicals, low moisture absorption, and low wear when paired with many shaft materials. The bearing delivers low coefficients of friction in dry operation and very good behaviour with soft shafts. Its absolute freedom from noise in combination with the high precision made it a good choice in organ-building from the very beginning. The tracker angle corner bearings, for example, were given hard, precise support in this project, allowing clearance of just five to ten microns. The thick-walled bushings in the wood hold their own despite the constantly changing environmental conditions, so there are no more rattling noises.
Installing polymer plain bearings can also greatly reduce regular maintenance work.
The bottom line also benefits: A fabric bearing would have to be replaced three to four times. Although the material price of the polymer plain bearing is slightly higher than that of the fabric bearing, the cost of dismantling the fabric bearing is thirty to forty times the material price.
But the biggest benefit of the
igubal series is that the organ-builder was able to take the next decisive step. The rod ends and clevis joints are some of the parts that are especially easy to use in stop action. Absolute freedom from lubrication is one thing that is important here. The polymer bearings are installed dry and, unlike fabric bearings, do not have to be soaked with Vaseline or impregnated with oily materials.