The top portions of stanchions 223, 224 include angle iron supports 240, 241 which receive downwardly de pending studs 244, which are coupled thereto via ad justable bolts 246. It will be apparent that the carriage may thus be operatively moved relative to the furnace tube by proper adjustment of bolts 246, which must of course be adjusted in cooperation with studs 230, previously discussed. In this fashion proper frame control in encouraged.