Font Editor on OS X? I have some fonts that has the same name (but they are different in weight). The default OS X font controller won't let me change their name. What are the editors out there can do it?
There is a method to change the internal name of a font - so you can see it differently from within an app - but you'll need to use Terminal, but it is not very hard: 


Make sure you are on an admin account 
Install Xcode (You'll need to login with your Apple ID for free, I'm not sure if this is actually necessary, so do it last if the next few steps don't work. I have Xcode installed so I can't tell whether having it makes a difference)
Download TTX 
Open Terminal (from Applications > Utilities)
Type cd with a space at the end, find the place at which you downloaded the fonttools-2.4 folder at (in step 3) and drag it onto the Terminal Window. Press enter
Copy and paste this: sudo python setup.py install
Enter your admin password when asked. You won't see it being typed it.

You've now installed TTX. Now I will tell you how to change the font name:
Type ttx with a space after it, find your font file and drag it onto the Terminal window. Press enter. OS X stores fonts at many places. Check here for more info. 
Now, in the font directory you just dragged the file from, you will find a new *.ttx file. Open it in Textedit.
Press Cmd + F. Type in fullname in the Find box. You will find something like: &lt;FullName value = "*" /&gt;
Copy the name in the quotes. Press Cmd + F again and paste this in the Find box. In the Replace box, type in your desired Font Name. Click Replace All.



  Note: If your font has a name that would commonly be used in a font file such as “Glyph” or “Asterisk” you may get some unwanted text replacement and possibly produce an unusable .ttx file. In these cases you should manually scroll through the font file and replace the instances where the name listed.



'Save As' the file. Leave the name as it is - or you can change it to anything because this is the file name not internal name. Make sure the filename is *.TTX. Save it in the desired location for the new font.
Go back to Terminal. Type ttx with a space after it, find your font file that you just saved and drag it onto the Terminal window. Press enter. 


You will now find the new otf file in the same directory. 


  Note. If you want to repeat this with a new file, start with step 8.


More info here (this is a little bit confusing, but it may help.)