The Inverness company, which already employs 130 people and has a turnover of around £30 million, said the move will create 10 jobs with the possibility of more in the future.
Chairman Doug McGilvray hopes the facility, the first of its kind in Scotland, can be open by spring. He said: "Like many other crane operators, our skilled workforce has an ageing profile. The nearest crane schools are in England so we've pursued the idea of establishing our own and we're ready to go.
"Applicants can gain very saleable skills from us and we'll be trying to cherrypick the best, offering well-paid jobs with Weldex."
The company, which worked on many venues for the London Olympics, said it has just experienced its best year of trading in Scotland in a decade with work on Orkney, Shetland, Dounreay, Nigg and the new Forth road crossing.