A limited number of parts are custom. For convenience we offer them here. Job files for laser cutting and PCB fabrication are available as part of our beta access and will be fully open sourced.
Misumi is an international supplier of automation components. Hint: You can copy&paste the CSVs from the bottom of this list directly into the Misumi order page. Hint2: In some countries they require a company account. If you are not purchasing through a company they usually accept the company field be "N/A or student".
Westfield Fasteners ships worldwide and offers sliding quantity discounts which is great for a project like this. Alternatively you might want to check out Screws & More and Schrauben Luchs. Be sure to order a bit more than strictly needed.
ThorLabs is an international supplier of optical components. All the mirrors, lenses and optical mounts come from them. FYI: Laser safty glasses are part of the list.
Mouser is an international supplier of electrical components.
ColeTech is an affordable and reliable supplier of laser tubes and accessories from China. Apart from requesting a quote by email they also have an ebay store. Most of the time they also offer laser + power supply packages. Make sure you specify the correct AC voltage (220V or 110V) when ordering. NOTE: Laser tubes are very fragile and do arrive broken occasionally. Before signing the package check for noises of broken parts, reject, and let Coletech know if this is the case.
GeckoDrive produces a very nice range of stepper drivers and also ships them worldwide. Budget Tip: In the US Hubbard CNC Inc has very good Gecko driver deals. Budget Tip 2: You can also go with the cheaper G201X drivers. Just know they don't have any protection circuitry and are easier to damage.
Nanotec ships worldwide. When ordering through their online store make sure to specify the rear-shaft option.
Lin Engineering ships worldwide and has very short lead times for the US. Make sure you specify the rear-shaft option.