The idea behind it is that those customers with uneven floors, who wish to have a knuckle foot with a generous amount of adjustment on say a bench or conveyor, really need to use an M10 foot, to give the longer threads some resistance to the occasional but inevitable side loads which they will meet.
However, this leads to two problems:
1) The 40x40 profile most commonly used for legs has a bore at the tapping size for M8, and must be drilled and re-tapped out where this is feasible (quite a long job).
2) Permissible thread pitch deviations under DIN standards, common in the male threads, very often mean that the feet will bind in long tapped holes, no matter how accurate the tapping.
The new base plate solves both these problems at low cost by having the M10 tapped hole for the foot not in the centre, but aligned with any of the T-slots in the leg. The centre hole is used for securing the plate to the profile with the usual M8 screw.
The new Base Plate 8, 40x40 M10s, may be seen on the Machine Building Systems website http://www.mbsitem.co.uk/item/products/base-plate-8-40x40-m10.html, and are available now from our Ripley factory.