I've just finished reading an interesting post from RZB about assembly instruction of the 1800bs model. I tool delivery earlier this summer of the shorter 1530bs.
I was surprised that the top was attached to the frame with only 2 fixings. One on the left leg frame and one on the right. These two fixings are well forward of centre and being as all the weight (of vices etc) and also most of the work is carried out on the first foot of the bench I thought that this might lead to the bench top bouncing at the back. I have added an extra fixing (screw bolt) towards the rear of the right leg frame but cannot find a suitable position on the left as the vice gets in the way.
I intend to add a sheet of 3/4" ply to the rear of the bench attached to the legs, stretchers and the top to add further rigidity, strength and weight. I have also mounted the legs on 4"x3" to give me an extra 3" on bench height (I'm 6'2") and will add 3 shelves. 2 on the stretchers and a 3rd on the feet. The gap between the lowest shelf (resting on the feet) and the lower stretcher will be filled with some left over stone blocks (the type used on driveways).
All of these mods should give be a much stronger and heavier bench.
AndyP
"Wisest are they that know they do not know." Socrates