Bob is correct when it comes to simple SELECT queries, but something about your post isn't clear.
the final Union simply selects these three Unions to create the final table.
A make table query ought to be making a table with the results of the union. Also, within the last week or so I read something about an effect pertaining to the order of union statements but I can't recall what that was about. Something to do with the first (or was it last?) union has an over-riding effect. I might be able to find it, but I think Bob might have been involved in that thread as well.
Bob: it was at AWF
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.