You might try looking for a different tub spout that has the female connection further inside so that you could use a threaded brass coupling and a short brass nipple to extend the copper stub out you now have.
Tub spout copper pipe too short.
However try not to wiggle the spout and pipe because too much jarring may cause problems with the plumbing in the wall.
The 1 2 copper pipe coming out of the wall is only an inch long and we need a minimum of two for the faucet to fit.
If the copper stub out penetrating through the wall is too short once the old spout is removed extend the copper tube length using the copper extension nipple.
How to install a slip on tub spout.
Or if your copper stub out is already long you could buy a tub spout that slides onto bare copper pipe.
Now cut another piece of 1 2 copper 1 3 8 long you may now solder the piece in using two couplings or two sharkbite connectors.
They also offer wonderful durability flexibility resistance to bacteria and ease of installation.
That means with the tile you can no longer reach the threads in the spout.
The result is the overall length of the pipe you need.
This video to show you how to solder it but it does give me an idea of what to do where to place your male adapter and how to cut and measure the line for t.
First figure how short you are let s say you re 3 8 shy of making a connection.
Copper pipes conduct heat well allowing hot water to stay warm.
The obvious thing would be go from the back and just replace the tube in the fitting but the back wall is plaster lath and in the middle of the living room.
1 to remove tile and cut through the backer board remove and replace the copper nub by soldering a longer copper tube to replace the shorter one.
Then measure the distance from the surface of the wall to the back of the threaded elbow inside the wall.
This resulted in water coming out of the back of the spout when i use the shower diverter on the spout.
For slip on tub spouts your copper pipe should be a minimum 1 and a maximum 2 7 8 in length.
Measure the length of your tub spout from the back edge of the spout to the front where the threads start on the inside of the spout.
Total the two and add 1 4 inch.
As i see it i now have two options to fix the problem.