keeping the x axis at the same length

Dear All,
I am plotting some data and saving the plot in tiff files.
The physical length of the x-axis changes, examples: when A) the y-axis goes from 0 to 4 with unit steps, the x-axis is shorter than B) when the y-axis goes from -1 to 4 with unit steps. This because the text "-0.1", with its minus sign, is longer than "0.1". This is annoying if you have to put A and B on top of each other. How to fix the length of one axis?
Thanks

Make ddd = p - 50
SetScale/P x, -50, 1, ddd
//PLOT A
display/W=(10,0,529,433) ddd[50,54]
SavePICT/O/E=-7/B=72/P=igorr as "aaa3.tif"
//PLOT B
display/W=(10,0,529,433) ddd[49,54]
SavePICT/O/E=-7/B=72/P=igorr as "aaa2.tif"
Try fixing the graph margins to the same value in both graphs. Right click on the graph, select "Modify Graph", and enter some numbers for the margins.
Right, as 741 said, the margins adjust to the axis text when set to auto. Constraining the left axis on both graphs will fix this issue. For your example, just add ModifyGraph margin(left)=50 before saving each graph.