Caster bracket types compared: plate, stem, grip and expanding adapters
The bracket decides how a caster mounts and carries load. Four common bracket types compared by mounting condition and equipment, with a quick rule for choosing by structure.
People shop by wheel first, but the bracket type decides whether the caster fits at all. Four common brackets match four equipment structures:
1) Plate type: bolted on a flat base with four bolts; highest capacity and most universal - trolleys and cabinet bases with mounting plates.
2) Threaded stem: screws into a tapped hole; compact with adjustable exposed height, common on instruments and test equipment.
3) Grip ring stem: plain stem pressed into a round tube, fixed by a grip ring - fastest assembly, typical for medical carts and displays.
4) Expanding adapter: stem plus rubber expander pressed into an unthreaded hole - no tapping needed, for sheet-tube furniture and light equipment.
Quick rule: flat surface - plate; tapped hole - threaded stem; round tube - grip stem; thin-wall plain hole - expanding adapter. Capacity decreases in that order. BLICKLE and DARCOR cover all four; e.g. the TPA 50-8G is a grip-stem model.
