[en] A 1/4 scaled model cavity of a uranium ion RFQ linac has been fabricated which has a favorable structure for the split coaxial RFQ with modulated vanes. The cavity is made of brass and is 200 cm in length and 40 cm in diameter. Since the vane positioning with accuracy better than ± 0.1 mm is required to get the desired azimuthal field balance, the parts related to the vane postioning have been manufactured within the accuracy of ± 0.025 mm. Accuracy of vanes positioning has been confirmed to be within ± 0.1 mm by measuring the field distributions between the adjacent vanes. (author)