Here are the step by step instructions for building the spectrometer that I am using at this moment.

http://publiclab.org/notes/dhaffnersr/08-09-2016/build-instructions-for-the-dh-4-0-v4-spectrometer

I have been also working on a far more stable entrance slit design and decided to include it with the build instructions. I have tested it several times and will post my results, I made one for my 0.12mm slit and my 0.09mm slit.

The slit I am using now is the 0.09mm one.

http://publiclab.org/notes/dhaffnersr/08-11-2016/complete-redesign-of-entrance-slit