When in the course of human events you decide paying to rent a machine shop is a fine way to loose money building your professional 4 foot long 120 pound monster pro projector
you look for alternatives !
If you buy the right T-slot tubing , it has a .250 gap in the slots. Black lexan or other stuff from plastics shops is usually .220. Thus the sides of the projector are plastic sheets. I get the better corner cubes and screws from the XE25 series from thorlabs. What I say in the manufacturers submission to get away with this with high power lasers is a trade secret, but I'm tired of seeing hobbyists getting clobbered making or buying enclosures. If you order your T-slot tubing from thorlabs, they will cut it to a few thou tolerances on the length, but its expensive. If you order it from automation4less.com, use a belt sander and a machining square to make the ends flat and parallel, you can make a heck of a projector for low bucks.
warning, black plastic is often transmissive in the IR.
So make some friends at your local plastics shop, get a AL baseplate blank from your local aluminum place, Ask whomever you order your baseplate sheet if they have any "drops", aka the scrap from cutting big sheets and make a projector the easy way. Buying the vendor's drop sheet is usualy cheaper then ordering a whole 4x8 sheet.
Use the plastic or aluminum corner cubes from thorlabs, dont try to use brackets unless you like milling!
How do you hold it together? the hole down the middle of the T-slot structural material is
tappable 1/4-20 or 5/16 course depending on who makes it.
Automation4less was small order friendly, didnt charge a cutting charge, fast and amazingly professional, but they cut the lengths with a chop saw, so your gonna do some filing or need to borrow a mill, or even a lathe with a 4 jaw chuck. This is fine because my local place sells it ONLY in 25 foot lengths! If you mix and match materials from different vendors, make sure they have the same dimensions on the drawings.
basic costs for a ~1 foot cube projector were
8 pieces of inch t-slot @ 3.55 each plus shipping (28.40)
5 pieces of black lexan cut to tolerance at the local plastics place, 6.58 each (32.90 + tax)
4 RM1G corner cubes at 13.00 each (ok I spent the big bucks for the metal ones, so what...) (52.00)
box of 100 screws SH25LP38 @ 26$ a box.
+ shipping
partz I use:
http://www.thorlabs.com/newGroupPage...&visual_ID=920
http://www.automation4less.com/store...s.asp?cat=1096
http://www.automation4less.com/tslots5.htm
I liked dealing with automation4less, it made life easier!
I posted this so people could save money and have a more professional, safer, projector without going broke.
Steve Roberts