Domagoj,
I've only been on the forum a bit longer than you, so welcome from one newbie to another!
I must confess that the vast majority of stock in my home machine shop came from dumpsters. Let me hasten to say, I had (and have) permission to "browse" the dumpsters in question. Like you, I don't have a scrap yard near by (at least, not one that allows people to come in and buy things), but I have found that certain businesses produce usable scrap. It doesn't have to be a machine shop or a manufacturer; one of my main "suppliers" is the scrap metal bin at a local university. (Again, I stress that I asked for and received permission!)
The usefulness of the scrap varies widely from week to week, but sometimes there are real treasures, though very often it is in the form of something that has to be disassembled to retrieve the useful bits. Very often the useful bits are shafts of various diameters and lengths. As an example, from time to time a pump gets thrown away, but the shaft is a nice quality of steel and the case is heavy cast iron, with some sections large enough to cut up for use as pistons or such. Just today, I was there and found a discarded piece of heavy lawn maintenance equipment - at least, I think that is what it was - the kind of thing that pokes holes in the grass to aerate it (?). Again, the part that was of interest to me was the shaft, but this time it is hexagonal shafting, around 30" long and around 1" in size (diameter? is that appropriate for hexagonal material?). I will have to remove the sections fastened to the shaft that have the "teeth" that poked holed in the grass, but at first glance this does not look to be too difficult.
In addition to round (and hexagonal stock), I often get useful sheet stock from this source. One of my favorite finds, that I've benefited from two or three times over the years, is discarded weight training equipment. The steel tubing that is used in the construction is of interest, and sometimes there are nice sections of flat material that are worth cutting out. Especially of interest to me are the weights, which tend to be 10 lb. rectangles of steel that machine quite nicely. Generally these weights are 3 to 4 inches wide by 10 to 12" long by 1" thick. That last bit is especially important to me, as it is much easier to find scrap that is 1/4" thick or less, so this stock is invaluable when I need something thicker. Yes, there are holes through, but for many projects I can find ways to cut it up that give me just what I need.
Obviously, there is an investment of time spent in the disassembly, and it is invaluable to have a metal-cutting bandsaw. I also find useful a metal-cutting disk in an angle grinder, and for flat or sheet material I have a plasma torch - very useful indeed. Sometimes it proves to be more trouble than it is worth to disassemble or cut out the useful bits, but when that happens I haven't lost anything but a bit of time; I just put any of my discards (including the parts I have removed that I have no interest in) back into the scrap bin the next time I visit.
One downside of my main "supplier" - I get quite a lot of steel of a variety of shapes and sizes, but only a very limited amount of aluminum - pretty much entirely limited to aluminum sheet that is no more than 1/4" thick, if that. I can get all of the 18 gauge stainless steel sheet that I could ever want from various appliances that get discarded from time to time, but rarely if ever anything thicker. I don't think I've ever acquired any round stock in either material from this "supplier." Ah well - I suppose I shouldn't complain if, once in a while, I actually have to pay for the stock I need ...
