I think I found the 3d printer I want here it is He 3d printer - best 3d printer kit with LCD control panel and Ramps 1.4
It looks like a variation of the Mendel, so it should have decent capability and a large user base. I didn't see any directions on the site, so you might want to see if they will email them. If the directions are not clear you could find it frustrating to build correctly. Do some research on the machine and it's strengths and weaknesses and you will not be disappointed. As an example of what I mean by research... the printer has a Bowden connection on the extruder. Bowden setups can be harder to setup if what I have seen on the RepRap forums is true. I have read enough on them that I decided that I didn't want one on the printer that I'm building. I'll use one at first - I know they do work after all - but I already have a plan for a light weight extruder to replace it.
Bowden tubes are not harder to set up. I strongly prefer them for two reasons: 1) Less mass on the print head means you can print faster without inertia problems, and 2) it's less complexity in the print head. If you need to do extruder maintenance (it happens!) or clear a jammed extruder (no more likely on a bowden than on a direct feed), it's a lot easier to do it on a separate extruder than on one that is attached to the hotend and X-axis carriage inside the frame of the machine. The majority of printers these days (at least repraps) are bowden tube machines. They're not hard to set up, and they're very reliable. All 3 of my printers are Bowden machines, and while the printers themselves all have had teething issues, none were Bowden-related. I like the Mendel design. It takes a good bit of attention to detail whilst building, but then most 3D printers have the same proviso: precision of prints requires precision in the build. What Mark said about seeing if they will send you the instructions is a good idea. The basics of Mendel construction are pretty easy to find on the web, but each specific variation has its quirks. The Mendel is no longer the most modern 3D printer out there, but it is still a very capable printer, and for that price, I would say it's a good buy and a good starting point in 3D printing. @Mark - the main reason that extruders are heavy is the NEMA-17. Replacing that with a lighter motor has caused trouble in the past. Still, you've done some remarkable things technically speaking, so it's possible that you'll find a good way to overcome the issues involved.
I guess the main difference in setup is the additional retraction the Bowden needs. But since you have to set the retraction for a direct extruder too, it would be incorrect to call it more difficult. I have a NEMA 08 stepper for my direct drive setup. Initial torque calculations say it should work, but time will tell. I will be able to print flexible filaments if I can get it to work.
A number of people have tried the smaller NEMA sizes but wind up with not enough torque. If you can get it to work, it'd be a boon for smaller format printers like the Tantillus. Actually, if you can get the basic Tantillus design to work with NEMA 08's for moving things around, it would call for a redesign that might add to the build volume within its stock envelope. I wish you great success and hope that you pull it off I'd love to have a small printer that I could sit on my desk at work I did see an ADD-inspiring very small format printer made from DVD tray-drive mechanisms that would be a good bit smaller with a NEMA 08 extruder motor. You're using 1.75mm filament or 3mm on the printer you're building?
It's theoretically possible, but I don't know of any way to control a stepper motor with standard hobby-grade RC gear. Most people who want position control for turret rotation use sail winch servos. And if you don't want position control, a geared motor is much simpler.
There are some pretty cute small printers out there. Richrap has a tiny delta. I saw it and said "I want one of the those". Then I realized that I would be spending almost as much as a full size printer to build it while giving up some serious build area. So I did a face palm and went back to my current build. I'm using 1.75mm filament. The key to getting the torque from the 08 is gearing. I'm looking at 60:1 right now as well as driving it at 1/2 steps instead of 1/16 steps. On top of that I'm using 24 volts which doubles my power. I'm not sure an 08 could be used to drive the printer carriages. The carriages move much faster than the extruder, so the loss of speed due to the gearing would be more of an impact. From the 08 specs: 0.100 kg*cm torque on 24 volts, 1/2 steps, and 10,000 steps /second (1500 rpm). Run some gearing calculations and you can quickly see if it is possible or not to use the stepper for movement.
The cute printer with the DVD trays only used the NEMA motor for the extruder; the guy used the stock motor drives to move the x,y,& z axes. Not impressive as a 3D printer but most impressive as a cool hack. The main reason that I think small 3D printers are cool is that they are good for techno-evangelism; easy to transport and show off. You are quite correct about the cost, though. I wonder if one could be done cheaper. The control electronics are about $23 direct from China, and a cheap J-head extruder about $9. NEMA 08's are about the same or higher than 17's tho BTW your Potemkin looks AWESOME.
