campagnolo low flage axle, spacing, can I space it 120?
 

If I want to space the axle at 120...do I simply remove the nut, remove the spacer, adjust cones?

Yes, and if you're putting a single cog on there you also need to 'shift' the hub way over to the drive side to achieve a good chain line, meaning more spacers on the non-drive side of the hub than on the drive side. The wheel also needs to be dished.

Thanks for the info. It will have a freewheel not single cog so I think it will work fine.

The following assumes you are using a quick release hub and skewer. If not, go back to your originally scheduled programming.

If the hub was originally 126 or 130 mm, you will have change to a shorter axle or shorten the stock one to assure the ends don't stick out beyond the frame's dropout faces and keep the qr skewer from tightening properly. A 120 mm hub normally uses a 131 mm axle and a longer one can be easily shortened with a hacksaw and the cut end filed smooth.