Economy of scale, cheap labour. If you have a big hydraulic press and a primitive foundry then probably the tooling is just a few days to a weeks work for someone with the skills. Then it's a case of stick tons of steel sheet through and pickle the results. However they must have a good deal with a distribution company - I buy a fair few bits directly from China for chainsaws, they often cost Less shipped to my door than I could post them for in the UK.
