|
Actually, "machine bushings" are not standard "flat washers". They look like flat washers but come in different thicknesses and materials. Flat washers are designed for distributing bolt loading on a larger area and also make up for over sized holes. FW's come in grades just like bolts, (IE: Gr2, GR5, GR8, thru-hard, ect.) While they vary in thickness, and O.D. (outside diameter) they are for use with bolts. Machine bushings on the other hand, come in all sorts of materials and alloys such as free-cutting brass, bronze, aluminum, ect. These are available in a far greater variety of ID's, OD's and thicknesses. Some are alloyed to make them resist wear while others are alloyed to give thrust bearing surface all depending upon the application. The brass/bronze tube type products you referenced are known as "shaft bushings" or "machine shaft bushings". These can be used for both rotational and thrust bearing applications depending upon the design of the bushing itself. There is some differential use of terminology as to what is a "washer" and what is a "bushing". Hard steel flat washers can, nd sometimes are, used and termed as a "bushing" in a specific application. For practicality, a "washer" is used on a bolt and a "bushing" is used on a shaft. If you really want to get picky about it, a flat washer can in reality be termed as "bolt bushing" because it does add a "space" or fills a gap. I know this sounds like a politicians answer but that's the best I got for you.
| 
