Using Diodes for voltage drop

Hi, Im building a walking robot, and intend to use a 7.4 volt lipo to power the Arduino Nano, with a seperate connection from the battery to power the servos.

My question is, is it ok to use diodes wired in series to get the required voltage drop to power the servos.

The servos are rated 6.0v max, and I have wired FR107 diodes in series to give me about 5.6V. 

The problem is each diode has a drop of  0.3 volts, so its taken quite a few to get where I need to be.

I used the FR107 diodes because I had a whole load in my parts bin.

Thanks for any advice.