Mr Thinks-Outside-The-Box a few weeks ago asked what the application was for a chunk of hot rolled steel that I had made a lot of holes in, here is his answer; it is a fixture for holding multiple parts for multi-operation machining.
We make many parts that are cut from round bar in a lathe then have milling operations on up to four faces. One is shown in the first picture, 2.250" dia. aluminum puck on the left finished object on the right, end facing the camera faced, blind semicircular tee-slot machined in this face, circular through hole on center, flat on what becomes the top with one tapped hole and one blind hole, part code engraved and serial number engraved. If we made these in the umpteen kazillions we would have multi-million dollar machines and robotic loaders and all sorts of fancy equipment like that; for a yearly volume of a very small fraction of a kazillion it is necessary to be more modest.
Second picture shows a fixture base mounted on a rotary table in a Haas Super MiniMill. Third picture is the fixture loaded with parts on the bench, a torque wrench is used for tightening the bolts to ensure they are all the same tension. Fourth picture is the loaded fixture on the rotary base. Fifth picture is 15 minutes and 2 seconds later with all the parts finished and the final picture is the fixture ready for reloading on the bench.
There are several advantages to this type of fixturing: Dimensions that have a critical relationship are easy to keep correct because everything is done at a single fixturing. Multiple parts can be processed which divides lost time due to tool changes over all the parts. In this example there are two holes with one of them tapped; even though five parts are done the tool change time is still a good portion of the total drill/tap process. With two fixtures one is loaded while the other is running which reduces machine dead time.
I don't have a tight grasp on the time it took to design and make the fixture, combine and rework two previously separate programs and prove everything out so it was ready to hand over to the machine operators. This is the kind of thing I do for the company and nobody keeps track of my times, not even me; it was certainly less than 80 hours and probably more than 30. However, even at the 80 hours it would be recovered within less than a year on this part alone and the fixture will be used for at least five different parts.