Click 
to expand Countersunk
Bolt.
Right-click Bottom Stack and select Bottom stack.
In the dialog box, select Washer: Plain Washers (Type A) - Selected - Narrow in Component.
Next you add washers and nuts to the fasteners.
Click to expand Countersunk
Bolt.
Right-click Bottom Stack and select Bottom stack.
In the dialog box, select Washer: Plain Washers (Type A) - Selected - Narrow in Component.
Notice that another component
line is automatically added. You can continue to add bottom stack components
or leave this as NONE.
Select 2 in Quantity.
This adds two washers per bolt.
In the second row of the table, select Nuts: Machine Screw - Hex Nut in Component and leave Quantity set to 1.
This adds one nut per bolt.
Click OK and rotate the model to see the washers and nuts.
