I found an unused stainless steel mountain bike brake cable in my box of bits, so I ordered some 6mm x 5.75mm brass throttle cable nipples from Wemoto. After watching a couple of videos on Youtube on how to solder the nipples on to the cable, I gave it a go tonight. I made a solder pot from a 22mm copper central heating blanking cap, which I heated up with a blowtorch and filled with lead free plumbing solder. Then it was a case of splay the end of the cable with a pair of long nosed pliers, clean the cable end and brass nipple with acetone, apply some plumbers flux paste to the splayed cable end and brass nipple, then dip it in the molten solder for about ten seconds. I then finished the job by leveling the hole in the end of the brass nipple using a gas soldering iron with a little more flux and solder. I was actually surprised how easy it was. I'll feed the cable up through the cable outer at the weekend, then solder the other end on. Even if I'd had to buy a new mountain bike cable inner, the whole job would have come to less than a tenner.