Quote Originally Posted by JAZZCNC View Post
In that case, you are bending the ball-screws because they are fixed to the top plate while the bottoms are fixed to the upright plates which your moving causing a twist on the screw. Also, the ball-screws must stay aligned perfectly parallel to the rails which they cannot do this way because you have them fixed to the top plate.

This design fails the golden rule of DIY to me.? Which is build-in Adjustment, adjustment, adjustment and bit more adjustment just for good measure?
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Well, the holes that secure the top plate to the back plate are a bit oversized to allow the bit of L to R adjustment whilst the idea is that the top of the side blocks and bearings stay fixed relative to each other - and after all the position where tram is spot-on should be when everything is perfectly aligned at 90 deg. If I were to do it again I would likely split the back plate into 2 stacked thinner plates to make assembly and tramming easier, but right now the important thing is to get this one up and running.And whilst it took a couuple of goes round the loop to adjust it all to get it running smoothly, it does basically work, it goes up and down quite happily apart from a slight wobble on one of the pulleys which I seem to have managed to bore out slightly off-centre, that's a job for tomorrow.