Ready Steady Eddy

[EddyCurrent]

Once I got the rails fitted to the gantry and the two lower bearing blocks added it was easy to see how to square everything up.
The gantry is bolted to the carriages at each end, the bolts were left slightly loose until the whole assembly was squared.



First an engineers square was adjusted to be exactly 90 deg. by using the flip over method mentioned previously, the fact it's a cheap Aldi one does not matter as you will see.
As silyavski pointed out recently, the Hiwin rails and bearing blocks have a machined side that should be used as a datum, so to these faces of the lower bearing blocks I clamped the engineers square.



All I had to do then was measure the distance between the engineers square and the long rails using a vernier. This was done at the end of the square and right up at the gantry so obviously when they read the same the gantry is at right angles to the long rails. The key point is that it's the two sets of rails that are being squared and not just the gantry frame. Also with regard to the cheap square, it can now be slid over to the other side of the gantry as it's clamped to the bearing blocks, and a similar reading can be made with the vernier. If the square was out of adjustment then the error would be multiplied at this side because the two long rails are exactly parallel. Once everything was adjusted the gantry securing bolts were tightened.