Click the layout tab for which you want to scale
lineweights.
ClickFile
menu Page
Setup Manager.At the Command prompt, enter
pagesetup.
In the Page Setup Manager, Page Setups area, select the page
setup that you want to modify.
Click Modify.
In the Page Setup dialog box, under Plot Scale, select Scale
Lineweights.
The lineweights
in the current layout are scaled in proportion to the designated
plot scale. When you are working in the Model tab, this option is
not available.