IS revisit with an Improvised Backer

We already discussed the unsupported MGN12H X-rail on the M0 and how the frequency drop was slightly more pronounced in the middle than I’m used to with my 300mm and Carbonara. Fortunately, I had a spare 5mm-thick bed mounting plate that I could cut and drill to make a simple backer for the middle of the rail. Three holes are directly from the rail, and the additional two also sandwich the XY joints.

The weight increase is approximately 30 grams, or about 5-6%, which typically results in a slightly larger drop in recommended acceleration. But that wasn’t the case here, since the lowest number has increased (pictures). The most reinforced rear corner number has slightly dropped, due to the added weight, while the weakest mid-bed acceleration is now almost identical to it.

No backer: 54k-63k MZV

With a short backer: 59k-62k MZV

I’d say this is a worthwhile upgrade, even on a 120mm, not necessarily because of the frequency uplift itself, but because of the better uniformity. I’m going to look into a more optimized (longer) version of this for the next wider release. This is just what I could do without modifying my existing XY-joints.