I had watched this youtube a few days previous to it being posted here. I noticed that the machine tools used were an interesting mix. One lathe is a geared head, and may be of English manufacture. The other lathes are of the same 'vee belt' headstock design as the Yogi lathe discussed in another thread on this 'board. The vee belt headstock lathes are likely locally manufactured. A Cincinnati horizontal milling machine is used to mill the keyways in the crankshafts. Another oddity was the use of small 3-jaw lathe chucks on the drill presses.
The crankshafts are likely being made as replacements for diesel engines in tractors. Could be a replacement for the crankshaft in a number of tractor engines. Massey-Ferguson tractors are prevailent in Pakistan and India, maybe produced under license. There are Mahindra (Indian made) tractors and a number of other manufacturers which we, in the USA, probably never heard of.
Watching youtubes of rural life in India and Pakistan, it is more common than not to see trucks and tractors grossly overloaded. Mechanics carry out repairs any way they can, often working with improvised tools on the bare ground. It is rare to see a torque wrench in use, and even ratchet wrenches seem to be in short supply. I am sure the crankshafts made in this youtube are going into tractor engines which will be run hard, not maintained remotely per manufacturers' recommendations, and run under overload quite often. Little wonder that shop was producing large numbers of replacement crankshafts.
Gasoline engines in automobiles and light equipment often use nodular cast iron crankshafts. I was surprised to see the crankshafts in this youtube were some kind of cast iron as well. This was obvious not only from the appearance of the raw castings, but the chips when the castings were machined. From what I have seen of Indian and Pakistani foundries, getting a consistent grade of nodular iron for crankshafts might be something of a grab-bag. Many of the foundries use coke-fired cupola furnaces, and some use induction furnaces to melt the iron. Youtubes of the foundries show a kind of laid-back way of doing things, with no precise weighing out of what gets charged into a melt. Scrap such as sprues and gates from previous runs of castings, along with scrap in the form of busted up junk castings and scrap steel, along with some 'pigs' (probably excess iron from previous melts) make up the charges. Maybe the foundries pouring diesel engine crankshafts are more exacting in their control of what goes into a melt.
The crankshafts are being made by manual machining, using micrometers and vernier calipers. Given the type of machine tools used and the type of measuring instruments used, the accuracy of the crankshafts produced likely is nowhere near what crankshafts produced by the diesel engine OEM would be. The metallurgy of the castings and the degree of accuracy of the machining raise a few questions. Namely: how well do these crankshafts hold up in service ? Chances are, like so much of what I've seen on youtubes about Indian and Pakistani mechanics and locally made machinery, the crankshafts and bearing inserts are setup so clearances are on the looser end of things to start with. Like so much else in that part of the world, the people work with what they have and know. Running an engine hard and with minimal maintenance is common. Changing crankshafts with a shorter service life is an expectable part of operating tractors in India or Pakistan. The main thing is the people find ways to make what they need and keep their machinery and equipment running.