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More specifically, my inspiration came from a site run by John C. Kleinbauer. His ideas for low cost components, such as using rollerblade bearings running on black iron gas pipe for cheap linear rails, were the key to my decision to actually *do* this project.
Now, down to the nitty gritty details. This is an overall picture of my router.
My router is made from 3/4" MDF, with 3/4" MDF based slatwall for the working table. The slots will serve as an integral clamping system, when paired with something as simple as a fender washer and a bolt. Another very good idea I got from the net.
The basic construction is simple -- U channels form the "rails" which you see in the picture. By stacking them atop one another, they become a very strong structure which should not exhibit significant flex.
The MDF was gotten from the "scrap bin" at Home Depot for just a few dollars, and the slatwall was free as it arrived damaged. Instead of 4 pieces of sufficient size, I settled for 3...and some damaged waste. Not bad for free! :-)
The rails are made from 1/2" (Y and Z axis) and 3/4" (X axis) black iron gas pipe. These were mostly short offcuts gotten for free at Home Depot stores in the Dallas, Tx area. The rollerblade bearings were salvaged from good-condition used rollerblade skates, purchased at local thrift stores. Happily most of them are of very high quality, and are gold ABEC-3 bearings.
The rails are mounted in alignment blocks, again inspired by some posts on the internet. They are simply a square of MDF with a large hole in the center, and tapped holes on each of the 4 edges. The bolts function as a low-tech "4 jaw chuck." They work surprisingly well, but tend to strip out easily. Making them from a more resilient material would be a better idea...perhaps more of the nylon that I used for the drive screws!
As I posess almost no metalworking skills, I used Simpsons Strong Tie angles to hold the bearings in alignment, and drilled them with my drill press. They work quite well, though in all fairness they are the weakest point in the entire construct, and will likely be replaced or upgraded soon.
The motors were salvaged from scrapped HP LaserJet III printers, and are all identical 100 oz-in steppers with a resolution of 200 steps per revolution. I was able to resell the toner cartridges and paper trays from the printers, on eBay, and actually made a profit while collecting my parts! I love it when things work out like that! :-)
To couple them to the drive screw, I used a flexible coupling. Being on a budget, I used some high pressure air pipe from Home Depot, and some worm clamps to make the connection. Simplicity itself.
The drive nuts are made from a Goodwill find, a nylon (I think) cutting board that I got for $1. I used an antibacklash design that I found, again, on the net. Basically the nut is threaded, and then nearly divided in half with a saw blade. A second tapped hole is put in, as well. By "flexing" the two halves of the nut together, backlash can be dialed out, sufficiently. You should be able to see the details of the nut's design, in the picture below.
The drive screws are simply allthread rod, 5/16"-18. I bought it at Lowes, as they had the best price.
Well, that's pretty much all of the information on its basic construction.
Next, I get to wire it up, and apply power. I found, at a local technology flea market, some stepper controller boards. I think I can modify them to take input from a computer, and act only as a translator and driver...they're based on the L297/L298 chipset, which is fairly common, and their on-board pulse generator is a 555. Should be simple to bypass it.
bravenet.com