Originally Posted by
routalot
I think you need to go all round the machine to identify the source of the flexing as it may have it's origins in a place that you might not suspect.To my eyes,the spindle mounting bracket is less than ideal as it is a long way from the tool tip and doesn't support the extremities of the spindle.I can't see an easy way to locate a dial gauge in the area so that you could investigate but you will really need to look for play in several areas.
I think some of the problem may have it's roots in the considerable height of the gantry as it will magnify what may be a tiny amount of play in the rail system.Similarly,the height doesn't help with the amount that the gantry uprights can flex and we can't see shat kind of bracing they have-if any.A dial gauge on a box to investigate play at the height of the gantry beam would be revealing.
A replacement set of supported rails for the Z axis would be a simple fix,but still less ideal than high grade rails,even the best rails in the world will show some play with the Z axis extended so far..I think the whole machine illustrates very well what happens when somebody imagines that a huge amount of Z axis travel is a great idea,but doesn't consider the implications.
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