How to align QwtScaleWidget with QwtPlot

[mirrorrorrim]

I create a QGridlayout and place a QwtPlot in the center and four QwtScaleWidget at the side of Top, Bottom, Left, Right of the QwtPlot.
And all the scales of QwtPlot itself are disabled by enableAxis( ..., false ).
I initialized the four scales like below:
scaleTop -> setScaleDiv( plot -> axisScaleDiv( QwtPlot::xTop ) );
...

But it is found that the four scales are not matched with the plot.
The value range of the scales is ok, but the ticks are not aligned with the grid of the plot.
How could i do something to fix this?Thanks…

If this is done, I will place several plots in grid and a lots of scales around all the plots.

Just like below:

blank scale scale
scale plot plot
scale plot plot
blank scale scale