Its a very common problem.
1. Right click on axis and select 'Edit Axis'. You will find following dialog box.
2. Select the 'Fixed' Radio Button. This option allows you to set you lower and upper limits for the values on axis.
3. In the first drop-down (marked by black line) select "Fixed' and assign a value of 45mil in the red box.
4. Leave the second drop down to Automatic. This should solve your problem.