I'm trying to understand some basic machinery and parts that are sold at a nearby store and I need a little help from you smart people.
1) The store sells bearings, they are round on the outside, on the inside, and come in little plastic packages. Some of the bearings also have a second piece with them that is black and looks like it has some kind of an allen bolt on it, but I have no idea what that part is for, it looks like it may fit on one side of the bearing ? No idea. So that's the first question, what is that part for, maybe it is some kind of seal, or used for lubrication ? Don't know. It is a ring and is smaller than the bearing itself, about halfway between the inside diameter and outside diameter of the bearing.
1a) Using bearings, I don't understand how the bearing "attaches" to whatever axle or shaft is going through it ? It isn't keyed in any way, just a smooth surface, maybe it doesn't matter whether the axle slips on the metal or the bearing turns so long as there is low friction ?
2) The store also sells something called a pillow block housing. Now what this looks like is something you put bearings into so that you can attach them to things, but it isn't obvious how the bearing stays in them, do you just hammer the bearing in ? (Hitting the outside ring of course).
2a) These pillow block housings have a grease fitting on them and a channel around the inside where grease can go, but it looks like if you just hammered a bearing in there the grease fitting would be completely useless, how would it lubricate a sealed bearing ?
2b) Is there an easy/standard way to seal the bearings in a pillow box housing so that they don't get dirt in them ? It looks like if the bearing just fits into the pillow box housing that for the most part it is completely exposed with no cover over it.
3) The store also sells something it calls a hub, essentially a ring that you can fit sprockets and/or pulley wheels to. Those hubs are keyed, and they don't seem to fit any standard sizes of pipe, so I am guessing that there is some kind of an axle or special pipe that you buy that those hubs fit on. If that is the case, do they come in standard sizes, and where do you get them ?
3a) This isn't so much a question, but related to the above, if you have one of these axles and you put a hub on it, the hub as an allen bolt type of screw on it that appears to be for tightening it down on the axle, am I right in assuming that the key is held in between the hub and the axle by the pressure created by tightening this bolt so that they key doesn't slip while the axle is turning ?
3b) How do the sprockets and pulley wheels attach to the hubs ? They seem to spin freely. Do you just tack weld them on ?
3c) The sprockets have two numbers on them, the first I don't know what it is, the second appears to be the number of teeth on the sprocket. Is it safe to assume that the first number is a chain size ?
In general I am also interested in knowing if there are any standard sizes of all of these components that are readily available pretty much anywhere on earth, especially the axle and chains, it did seem like most of the hubs were designed to fit just a few axle sizes.
Thank you for any information.