A seat support with adjustment systems allowing a height and swivel adjustment functionality of the seat in a manner free of any wobble and shaking motion. The seat mechanism for height and swivel adjustments have screw adjustment applying a pre-load on a resilient component which gives a resilient force on a load bearing surface. The load bearing surface guides the seat part in motion during seat adjustment in a way to reduce friction and wear with use in time. The screw adjustment and the resilient component are configured such that play in guiding of the seat part in motion during seat adjustment is eliminated regardless of fabrication and component variations, and wear, with use in time. A screw adjustment locking device is configured to assure a stable adjustment with use in time.