Or search: callus, curing, symptom, annealing, tempering, callosity, solidifying, congelation, congealment, plastination, calcification, solidification
2 Syllables: SU
arching, argent, arming, bargain, barking, barring, carving, charging, charming, charting, darkening, darling, darting, Darwin, Darwin's, farming, farthing, gardening, guarding, Harding, harming, jarring, marching, marking, Martin, Marvin, parking, parting, quarreling, sharpening, smarting, snarling, sparkling, starting, startling, starving
3 Syllables: SUU
bartering, discharging, harboring, harbouring, hardworking, harnessing, harvesting, marketing, marshalling, pardoning
3 Syllables: USU
alarming, departing, disarming, discarding, disheartening, embarking, enlarging, imparting, regarding, remarking, retarding
4 Syllables: UUSU
disregarding

Found 58 words across 4 groupings. Skipped 4 excess words of a similar stem.