I have made hundreds of sets when I worked for Caltrans in the high country . Anytime we were not plowing snow in the winter on Interstate 80 ,it seemed like we were rebuilding or making new chains . I don't think you will save any money ,to speak of , building your own . You can buy the sidelink and cross link from most tire chain manufactures .We even started hardfacing the old ones to see how they worked and boy did they tear up concrete or asphalt pavement ! That got nixed in a hurry ,but I suppose they would work ok on gravel or dirt .
If you live in snow country ,stop buy your local highway dept . Let the equipment operator's know you are interested in big tire chains and if any of the employee's find one of the size you need you might be interested in buying it . We just threw out the ones we found ,but a few guys would try and find a mate over the winter months and then sell then to local truckers or contractors in the summer months .They,the big tire chains , can really stop a snow blower in its tracks ,when you suck one up in the fan or auger !!! Some needed lots of repair , but usually the side link and latches were in good shape .
Big Al