Some time ago i bought 5 red laser diodes which are in a cylinder with 18mm diameter which holds the diode and collimator with lens.
It came to my thought to use these 4 x 150 mw to make a simple quad setup with a pbs cube.
Since i don't have materials/expertise to create something to hold the modules in place i got a tip from a friend who pointed me to www.hebu.nl here they have special pipe holders from 6 to very 58 or so mm. I got 4 sets of module holders, all together, for 12 euros.

Here are the items.
fitting2.JPG



fitting.JPG
There is also a baseplate that is a little larger with two mounting holes, i got those with the set.
page 274 on http://www.hebu.nl/catalogus/hoofdstuk5.pdf


Michel