Liquid Nitrogen for shrinkage in machining

This machinist uses liquid nitrogen quite frequently in his procedure for installing a stock steel sleeve when repairing an end housing from an electric motor.
When a bearing area on one of these housings becomes worn out, the two choices are 1) to purchase a new housing, which may not be available or may be quite expensive or 2) to repair it in the procedure this skilled tradesman is demonstrating.
From start to finish the complete machining procedure takes him approximately 2.5 hours.
Much quicker and more cost effective than the alternative.