If your aim is to make a low divergence laser, you could just use a laser diode in a heat sink without a expansion lens in front of it because the natural expansion of the beam as it travels forward can be used to advantage, if you can match up the right tube and collimation lens for it. To do so, first you have to measure how big the beam expands at a given distance to know both the length of the tube you need as well as match the diameter of the lens and its focal length. A bigger spot means a longer tube as well as a longer focal length, but these aren't hard to determine with a visible spectrum laser, just spot it on a wall and take measurements. From what I've seen suggested, the diameter of the beam should not be greater than about 80% as wide as the lens used to collimate it.
When building the holder for the lens, or if using a suitable telephoto camera lens assembly, of course, you want some wiggle room to adjust the focus. The lens should be set in a holder which allows adjustment in and out to find the right spot for infinity focus. To find the lens placement and range of movement, you can experimentally determine this by moving the lens you intend to use to and fro in front of the beam while spotting the beam on a close wall and then on a far wall to make sure the diameter doesn't change, that should get you close to the center of the focal range you need to have, but allow an adjustment range of up to an inch either side of that and you should be good, half of that ought to work well, but more adjustment range is what I'd design for, just to be sure.
If you start out with a single mode laser diode with only a 5μm chip output aperture (.000005 meter) and it expands to just 50mm (.050 meter) that's a huge amount of expansion, unfortunately, there is a limit of mRad reduction due to a diffraction limit related to lens quality and size, smaller worse (which I am still trying to understand), but regardless still a uber low divergence. Only thing is, most diodes have such wide fast axis outputs, you need a wide shroud/tube to mount the collimation lens on which expands at about a 30+ degree angle for most diodes, up to 45 degrees for some of the multimode diodes. Because of this, the beam from the diode expands too fast and gets clipped inside a normal telephoto tube when using the raw output from a laser diode. Of course, the rate of expansion could be controlled with the right expander lens, but my thought was to build an expander without the extra input lens to reduce the total losses. Example of cheap ebay telephoto lens:
Vivitar 200mm 1 3 5 Auto Telephoto Camera Lens 62OPENING Screw Mount | eBay
Back to what you were asking, as stated above by lazeristasUVISIR, with the right expander lens on the input (concave or bi-concave) and a big plano-convex/PCX output lens (replacing the original bi-convex lens) you could conceivably use the housing from a camera telephoto lens. I suppose it is possible to do so without replacing the output lens too, depends on some factors I can't speculate upon without having the particular lens assembly to study, and the help of a few of my friends, I still have lots of questions myself.
I just bought a 6 inch/150mm diameter 160X beam expander, now that's heavy! Gave up on trying to build my own due to the difficulty of finding a nice shroud. I don't have to concern myself with diffraction limited lenses and accurate mountings now, this has better than 1/2 wave accuracy at 532nm. Thank you ebay, could never afford this at the price of a new one.