threadably engageable in a block 26 on the left hand end of the support platform 18 for selectively retaining the clamping assembly 20 in a closed position as shown the system 16 is shown clamping the nozzle guide vane 10 with the plates 14 extending behind and in front of the system 16 as shown in fig2 the system 16 is engageable with the two aerofoils 12 two shallow n shaped beams 28 are mounted in a parallel alignment on top of the assembly 20 each beam 28 is mounted by a bolt 30 which engages with a hemispherical section block 32 and through which block 32 the bolt 30 extends the block 32 locates in a correspondingly shaped recess 34 in the top of the respective beam 28 to permit limited pivotal movement of the beams 28 relative to the bolts 24 a clamping arrangement 36 is pivotally mounted to each of the side limbs of the beams 28 towards the lower end thereof each arrangement 36 includes a bar 38 which extends through a recess in the lower end of the respective side limb of the beam 28 and is pivotally mounted thereto about a generally mid point of the bar 38 an engagement member 40 extends downwardly from each end of each bar 38 through an opening in the clamping assembly 20 a trapped ball bearing 41 is provided at the free end of each engagement member 40 and the ball bearing 41 may have one or more flattened faces engageable with the respective aerofoil 12 as can be seen in fig2 a shorter.