RepRap Intro Video Script

I finished the first draft of the script for the introduction to the series of videos I'm doing for the Mendel build. Also, by way of update, I ordered the RAMPS electronics assembly which, I believe, was the last remaining component I had to get to finish the project. When it arrives there will be nothing stopping me from building at least one whole machine. I WILL start shooting (and building) very soon.

SCENE 1: INTRODUCTION

CLOSE UP:

KEVIN

My name is Kevin Wixson. I'm making a 3D printer.The 3D printer is a transformative technology that turns digital files into three-dimensional objects...

CUTAWAY: Detail of RepRap printed part

KEVIN

...like this. Unlike a 3D movie, which produces only an illusion of dimensionality...

WIDE: Kevin sitting at work table with array of Mendel parts in front of him

KEVIN

...a 3D printer actually creates a real object.
It deposits layers of material on to a surface. Let me try to explain.

CUTAWAY: Illustration of 3d printer process

KEVIN (VO)

A printer head for many 3D printers is like a hot glue gun, it squeezes out, or as we like to say it extrudes the printing material. There are a lot of possible printing materials, but usually we're talking about some sort of plastic. The print head moves back and forth in one direction, while the platform moves underneath it like a piece of paper, except that when it's done with one pass of the "paper" or workspace, instead of spitting it out into a tray, it goes back to the beginning, moves the printer head up a little tiny bit, and prints on top of what it printed before.

CUTBACK: 

KEVIN

Right now there are no 3D printers available for the consumer market, only expensive commercial units. So the only way to get a 3D printer is pretty much to build one yourself. I'm making a RepRap 3D printer.

CUTAWAY: Reprap web site, photo of Adrian, w/ Ken Burns effect

KEVIN (VO)

RepRap is an open design project developed in 2005 by Dr. Adrian Bowyer, at the University of Bath in the United Kingdom.

CUTBACK:

KEVIN

Since it is an open source project, the plans and electronic files you need to build one are free to download and share with others, but more importantly you can make little tweaks to the design. As long as you share those designs freely in turn, you can do what you want with them. Because of this, a lot of people have gotten directly involved with the project and it has improved rapidly. 

CUTAWAY: Photos of Darwin, Mendel, Ed Sells, Prusa Mendel

KEVIN (VO)

There have been two official revisions, the original, called Darwin, and Darwin's successor, the Mendel. There are variations of the Mendel, named after their creators. The first Mendel was created by Ed Sells, a research assistant to Dr. Bowyer, and it is sometimes referred to as the Sells Mendel. The Prusa Mendel is a variant of the Mendel created by someone in the RepRap community.

CUTBACK: 

KEVIN

I will be making a Prusa Mendel, because it's the most popular variety right now, easier to build, has fewer parts, and fewer things can go wrong with it, or so I'm told.

CLOSE UP:

KEVIN

Personally, I think the term 3D Printer is a bit  misleading now, given the popularity of the term in movies and TV technologies. As a science fiction fan I might like "Matter Converter" better. If you ever get a chance, read Neal Stephenson's book The Diamond Age for a story that incorporates on-demand personal manufacturing like this. And of course, there's always the Star Trek replicator technology to think about, even if it can't yet make tea, Earl Grey, hot.

WIDE:

KEVIN

Whatever you call it, the purpose of these machines is to take a universal material, in this case a filament of plastic, like this, and turn it into specific things, either artistic or useful. Usually you would use it to create the first of something new, a prototype. That's why the RepRap machines are in the same class as other rapid prototyping mechines, like computer controlled milling or routing machines. 

CLOSE UP:

KEVIN

With these machines you can transform something that exists only in a computer into something real that you can hold. It has a real magical quality to it, I think.

WIDE:

KEVIN

I mean, with this machine I can summon an object into existence through mere force of will, almost. Stephen Hawking could, if he didn't have better things to do, design an object and it would appear there on the printer at his desk. That's some powerful stuff.

CLOSE UP:

KEVIN

What motivates me are a number of things: it's just cool, it's a technical challenge, I like the idea of being able to use it to build other things. But first and foremost, I have to say, (aside) and this is going to sound a little wierd at first (/aside) I'm taking a cue from Michael Moore. 

WIDE:

KEVIN

In the conclusion to his movie Capitalism, A Love Story he says, "Capitalism is an evil, and you can not regulate evil. You have to eliminate it, and replace it with something that is good for all people, and that something is called Democracy," and then he asks the audience to help out with that.

CLOSE UP:

KEVIN

When I came across the RepRap project I thought of this scene and asked myself, "What is it, when you can download an electronic file for an object that an average person designed and published on the Internet, who allows you to use the file and asks nothing in return, and you use that design to just print out the object, and then you have it? You own this thing that came from little more than a feed of raw materials." What kind of economy is that? It's not capitalism, barter, or trade of any kind. It's not socialism, or communism. It's something new, isn't it?

WIDE:

KEVIN

The web is said to enable a democrotization of information. It allows the free exchange of ideas. If it also allows the free exchange of material goods, isn't that also a democratizing force?

CLOSE UP:

KEVIN

I know how this sounds, believe me. But I'm not alone in this train of thought. In an article about the RepRap project, the Brittish newspaperThe Guardian said it, "has been called the invention that will bring down global capitalism, star a second industrial revolution, and save the environment." 

WIDE:

KEVIN

I'll bet not a lot of people know this, but Dr. Adrian Bower himself intended from the outset that the RepRap project would have revolutionary effects with serious implications for politics and economies. In a white paper for the project written in 2004, and kind of buried on the RepRap wiki, Bowyer cites parts of the Communist Manifesto written by Karl Marx and Frederick Engels. He quotes, "By proletariat is meant the class of modern wage labourers who, having no means of production of their own, are reduced to selling their labour power in order to live."

CLOSE UP:

KEVIN

He goes on to say that while the violent  revolutionary proscription of such communist ideologies are decidedly and definitively wrong, the "diagnosis is essentially correct; it is a commonplace that people with resources can quite easily use them to acquire more, but people without have to try exceptionally hard to get anywhere, and most of them never do."

WIDE:

KEVIN

Bowyer goes on to describe his remedy to this essential dilema. He writes, "The self-copying rapid-prototyping machine will allow people to manufacture for themselves many of the things they want, including the machine that does the manufacturing. It is the first technology that we can have that will simultaneously make people more wealthy whilst reducing the need for industrial production." The title of the page where this appears, and also the motto of the project, is, "Wealth without money."

CLOSE UP:

KEVIN

I think that we can see in this project a day in the not so distant future where the role of industrial design and production are significantly diminished. The econimic forces that govern our lives will shift. What that means, ultimately, is difficult to say. I choose to believe, however, that it will have a net positive effect on society. I also think that regardless of intent, it's inevitible that this technology will become  commonplace, and I want to be part of it early on.

WIDE:

KEVIN

So, I'm going to build a machine, learn how to use it, and I intend to share what I discover along the way. That's it for now. See you again next time.

AC Window Frame Progress - Vent Port Mounts

I am nearly done with the A/C Window panel project for our third story (attic) I started here, and updated here.

I got the window frame all glued in and ready to go. Working on the window frame I reflected on the idea of "workmanship" and essentially came to the conclusion that it relates directly to the amount of time you commit to screwing with something to get it just right. It took a long time, is what I'm saying.

I'd routed out spaces for the clips from the vent port to lock on, but I didn't mark depth and started out with a dull tool. Tip: when it mostly burns instead of cutting, it's time to throw it out and get a new one. I had to cut the plywood pretty thin, so I figured it could use some more support.

The guy at Lowe's sold me on these for use to hold in the panel to the window frame, but they aren't going to work as intended in my situation. Not wanting them to go to waste I thought these would make a more elegant solution than bolts and washers, my original plan.

They needed some modification, however, so I got out the Dremmel and sanded them down to be just a little taller than the lip of the vent port.

It turned out pretty well, I think. The narrow pitch to the screws did actually find sufficient purchase in the soft plywood to seat securely, but I wouldn't want to push it. I drilled pilot holes slightly smaller than recommended, and not just because I'm missing the bit of the correct size.

Here's the dress rehearsal for the panel. As you can see, the ducts are held securely in place by the window screen hardware and clipped to the panel.

All that's left to do is paint it, build the stand for the A/C unit itself, and clean up those ducts! Almost done, and then I can get back to the RepRap project.

AC Window Frame Progress - Lath & Plexi Cut

Continuing with the A/C Window panel project for our third story (attic) I started here.

Of course, at every conceivable opportunity I try out my ideas, try the fitting of pieces to cut down on the opportunities for a nasty surprise. What works on paper never exactly pans out when you get to cutting. For instance, cutting any kind of frame with 45deg corners is tricky business, even with a miter guide (bought special for the occasion, I might add.) Also, in an attempt to get the frame just a little shorter because it had too much wiggle, I cut just a hair too much off and had to trim the long pieces. This made the long pieces too short and to fit the window, so I had to dremel the edge with a sanding attachment until I got it to fit. So yeah, trying to out with dry runs are important.

Got to gluing. Remember to take caution when screwing through lath, it's weak stuff and prone to crack and if you don't have your driver set to the lowest torque setting you're going to strip the hole. To clamp all the pieces in place I used wood screws (with pilot holes) to keep everything locked tight while the glue set. It also helped to hold in one side while precisely placing the others. When I was ready to glue I'd unscrew one side, spread the glue in, screw it back in pace and then unscrew the next section. I left the top unglued to fit in the plexiglass as findal step.

Air Conditioner Window Mount

Portable air conditioner for our 3rd floor/finished attic.





We've had this portable air conditioner for a number of years, and for years I've been trying half baked ideas for overcoming some of the challenges it presents. One such challenge is to mount the ducts to vent air outside. The idea has been to replace the screen in the window with something that holds the vents securely but lets the light in. Last year I just put up a sheet of plexiglass and held it in place with silicone. It was ugly. So I'm building window mount from wood with a plexiglass window (recycled from last year's project).

Once again Adobe Ideas on the iPad serves as a great application for drawing up plans.






Got the materials at Menards and wound up buying a bundle of 50 pieces of lath and a 4'x4' sheet of 1/4" birch ply.

UPS Suck Becomes Endemic

I couple days ago I mentioned that UPS Has Some Sucky Drivers and that's true, but it turns out that the company kind of sucks too. Precisely, it has one sucky policy.

When the Joby Gorillapod finally showed up, both packages were delivered, the replacement order and the original both. So, although I could have kept it and nobody would have been the wiser, the right thing to do was return it to Amazon. When I took the return to UPS to send it back to Amazon the clerk at the UPS office asks me, "Do you have tape?" I say, "no" and she tells me that it will cost a dollar to have them tape it up. Seriously? UPS can't afford to take half a second and a couple feet of clear packing tape and just do that for customers as a courtesy? Really? UPS, you suck.

So it cost me not only the time and trouble of a trip to the UPS store to do the right thing, but also a dollar. Does it ever pay to do the right thing when corporations are involved, or should I just say, "screw 'em" and keep the extra $60 order next time?

I guess Amazon needs to strike a deal with UPS to include packing tape service with their

Joby Gorillapod SLR-Zoom Rocks

I finally received the Joby Gorillapod SLR-Zoom I needed to complete my overhead rig for the Mendel shoot. I hadn't been sure it would work until I set it up. As you can see, even with the full rig of of the matt box and french flag to ward off glare it holds firm in on the horizontal bar. I'm glad I got the ball head with it, though, or getting it lined up would be a bit of a challenge.

UPS Has Some Sucky Drivers

I was supposed to receive my Joby SLR-Zoom order from Amazon today and I was really looking forward to getting started with shooting for the Mendel project. However, UPS screwed up and must have delivered it to the wrong address.

We have a bad history with UPS at this house. Sometimes their tracking says "no such address" even though they've delivered here before. I really think that the UPS drivers who don't normally deliver here may sometimes feel like they don't want to go to the trouble, and they put "no such address" as an excuse and leave. I get it, we are hard to find, but seriously! Once someone at UPS has figured out where we are is there no way to share that information with the rest of UPS, like put it in our record or something and not have this problem any more.

Apparently not. Amazon's online help says to call the carrier, and I did. According to them the only way to get something added to our record is for the shipper to complain, and when I finally did figure out how to contact Amazon by phone they said they can't do the thing that UPS wants to get them to note the record.

Amazon Tip: If you don't receive your order from Amazon even though UPS tracking says it's been "delivered", you need to go to the "returns" process at Amazon. That's counter-intuitive, clearly, and it threw me off for a while. In the "returns" process there is a place to indicate that you did not receive your order, and then from there you follow the yellow brick road. It ends up, optionally, that instead of calling them you input your number and they call you. They were prompt and the customer service agent could be easily understood. They are sending me a fresh box. If there are no more f**k-UPS then it will be here Friday.

So, no shooting until Friday at the earliest, but realistically I'll probably get started next week.

ROS Robotics Platform

Recently a robotics company called Willow Garage has caught my attention. They have developed three prototypes at this point, one of which I'd seen on various Discovery programs. The Texai robot is a "remote presence system," kind of like a mobile, remote controlled, teleconferencing system. Their PR2 robot is the latest and greatest, and their most ambitious project to date. Think Rosie the robot from the Jetsons cartoon. PR2 even looks something like Rosie, and the project strives to realize the promise of a home robot assistant with social skills. Then there's the robot I'm most excited about, and that's the Turtlebot. The Turtlebot is a development platform for creating knee to waist-high robots that can navigate a home environment. It uses a Microsoft Kinect system as its sensing suite, and a iRobot Create provides the mobility.

First off, it's great that this company is basically taking off-the-shelf components and combining them to quickly produce a fairly robust robotics system at low cost. I have been dreaming about the possibility of having a robot on the first floor of our house which I could access when I'm upstairs or in the basement to see what the dogs are up to, and keep an eye out for my wife coming home from work. It could be connected to a network of fixed sensors around the house to detect activity around the house and go to a nearby window to investigate and record. Maybe the next time someone tries to steal a bike off our porch we could catch them in the act. Or, when the UPS driver actually finds our house for a change we can get a text message that a package has arrived, including a picture out the window of the box. I'll be getting a Turtlebot and building the POLYRO project some point soon, I hope.

But I'm burying the lead, really, about what's so great about Willow Garage. Besides their hardware, what they will be known for will be development of the open source software called ROS, which stands for Robot Operating System, not surprisingly. It comes with libraries of code and applications of particular use to robotics, including visual object tracking and recognition, navigation and object avoidance, and hopefully one day even voice and speech recognition. As an open source project (and such a cool one at that) we can expect to see rapid development and I have every reason to believe it's getting in the game early enough that it could be the major player in home robotics software in the future.

I think it could even be useful to applications besides just mobile, home/office robotics hardware. Why not add a bunch of sensors and controllers to the house and use ROS to control the entire system as if it were a big immobile robot? It's fun to think about anyway.

B-Squares: Modular Solar Power for Gadgets

I'm a backer! B-Squares is a project on Kickstarter, which means that they need a commitment of a certain amount from any number of backers in order to move forward, and backers don't have to pay anything if they don't reach the threshold for funding. It's small-scale venture capitalism.

B-Squares aims to commercially produce hackable, modular solar powered gadgets. It has both an Arduino module and a "proto" module that pretty much has a blank PCB (printed circuit board) in it for you to play with. Through those two modules I think there are a ton of opportunities for neat little things, remote sensing stations in particular. Put them inside big pickle jars on poles and you can have a pretty much autonomous outposts in the wild.
I went in for $100 to get the developer kit when it comes out. I'm really excited about the possibility of powering some robots with solar!

Creative Process: Building Overhead Video Supports

Finished (but not painted) upright floor joist clamp and horizontal support bracket.

"I love it when a plan comes together."

I love the whole process, actually, from conceptualization to execution. I often fizzle before getting to execution, so it's particularly sweet when I get there. The creative process is no mystery. Processes are not generally a mystery, by definition.

Step 1: Have an idea, an urge, or a problem. Define it. I find it helpful to start with words.

Problem, I need a way to secure my expensive video camera over my work area while I'm shooting in the studio... I mean basement. 

Step 2: Ideation. This part has no tangible output. It's not something you can force, either. You just have to give yourself room to think about the problem. That usually means time. Don't try to think about it either, or at least don't keep trying. Do other things, especially menial things. Thoughts will come to you and you just need to let it happen. The danger is that you give yourself so much time that you stop thinking about it even subconsciously. It's hard to gauge, but eventually you get the hang of it.

Since I have Camera A shooting from the front, I don't want a tripod in the picture. Also want the camera looking straight down. First thought is to use bar clamps on the floor joists and suspend a rod or 2x2 between them, but that scared the dickens out of me. 

Step 2: Visualize the idea (thumbnail)

Step 3: Repeat ideation, then refine idea.

Enough to go on before shopping for materials. Bought stuff at Home Depot, and got to thinking. Why cut the 2x4 when it already came in a handy 92" length? It would be stronger and easier to handle if it was just one piece. Got to drawing again.

Step 4: Test your idea. In design and engineering it's called prototyping, but in all creative endeavors there are ways to mock up your idea and experiment with the things that bother you the most from your refined idea. What part would you like to validate?

Step 4: Begin working. Now you have to be a bit fearless. You need to be confident that as things progress you can solve unexpected problems. You have a plan, and that should give you courage. That all sounds touchy-feely, but it's the honest truth. Psychologically that's the state we're in (i.e., fear) at this stage. So, pshych yourself up and get at it.

I glued two pieces of 2x4 together to form the clamp, secured at the bottom with a bolt and tensioned with another bolt through the hole in the picture below. This way the upright support will come in just two pieces, and will be easier to handle, like I'd hoped.

Step 5: Solve problems and strive for simplicity.

In the drawings I had considered what to do with the two bolts going through the bracket. What I drew was a inset in the middle piece of wood. While working I realized this would be difficult to align, and I didn't need two bolts going through the clamp at the bottom. In fact, that might make the clamping less effective. So, first I cut the clamp short enough that it would be above the bolt. Then I realized that the bolts I'd gotten weren't long enough to go all the way through the 2x4 and the clamp anyway. I routed out the cavity that was going to be in the middle piece in the first place, but in the main board itself. Then I realized that with this design I could leave the clamp loosely joined to the main support and it can swivel down, making setup easier. Simple solutions tend to be more elegant.

Step 6: Finish. Don't stop. Don't skimp. Don't cut corners. Fight impatience. Don't be a perfectionist either. Get it done and let it be.

It worked! Set it up and called Desi down to see what I'd made. Just need to let the glue dry and paint it all white. Then I'll be done. The camera will be suspended from the horizontal 2x2 by a Joby Gorillapod SLR-Zoom. $35 on Amazon. 


Step 7: Enjoy your success. You did it!

Part Specifications Matter

1. Stepper motors arrived today. Yay!
2. Nuts and bolts. Now I think kits are the way to go because of this stuff.
3. Bag o' printed parts off eBay. They were the first to arrive.
4. Rod. Not as hard to get as I thought. Fastenal had the drill rod.
5. Spirit level, yard stick and calipers. Measure THEN cut. :)
6. Instructions. Won't actually use iPad around dust.
7. Springs. 12 to a box. Need less than one whole one.
8. More hardware, arrived today. Need a new box.
9. Accelerant (Mountain Dew)
10. WD40 -- eternally useful

Almost there! Still missing: electronics, hot end, pesky unspec'ed springs, and ... 5/16" washers, damnit!

True Value let me down. Not their fault entirely, I suppose. I asked for "5/16 in. washers" and they gave them to me. What I failed to note, however, was that the ones needed for the project have an outer diameter of 5/8" and the ones they handed me have an OD of 7/8". So, while try-fitting some of the parts tonight I realized that I'd gotten the wrong ones, and the ones I have won't work. So there's another $5 I didn't need to spend. Anyone need some washers?

Moral of the story: pay attention to all the exact specifications of the project, even when you think something is a no-brainer. 

Build Your Own CNC

Down time is a dangerous thing when you're hot to build a project. I am waiting for delivery of a whole bunch of parts for the RepRap machine project that I bought online Monday, and wanting to take a break from thinking of that particular project, got surfing.

My next project has been selected, I think. It was a toss-up from the beginning whether I would do the RepRap 3D printer or build a CNC mill first. The RepRap won because as it turns out, it's what I could get funded first. These kickstarter projects, Modular Desktop CNC Machine, and DIY Desktop CNC Machine have recently added fuel to the fire, though. They lack one important ingredient, however, and that's that neither as far as I can tell is open source. It's important to me that I build from a base that I can share after it's done. These machines I'm building are going out into the community, and if people are inspired by the projects I want to be able to share time, experience and materials with them. I could probably do that with the DIY Desktop CNC Machine project by Stephen McGloughlin, but I know that the other project is NOT open source at all because I asked and they said "no".

Come to think of it, though, there are actually two things. I also envisioned a CNC mill that was as large as Ben's on the Ben Heck Show. The Kickstarter projects are just tabletop machines, and don't scale up. I probably will end up building a desktop CNC mill at some point. There's no sense having a 4' x 8' cutting table when you're working on a 2" x 3" PCB after all, but I'm definitely looking at one large enough to cut cabinetry and other larger-scale pieces.

So, looking back on the Kickstarter projects I was actually considering their respective merits, supposing I would go with one of them anyway, but gave "open source diy cnc" a whirl on the Google machine. After trying quite a few, and lingering a while at diylilcnc.org I eventually stumbled on the motherload, buildyourowncnc.com. The reason I found it so exciting right away is that this project starts with, as the author puts it, "a cheap saw, cheap drill, cheap metal cutting saw, a 5/16" tap (a device that threads the inside of a hole to enable a screw/bolt to fasten) and a cheap screwdriver. When I say cheap, I mean it literally, and economically."

Plus, the guy that developed this project is just cool.





In the videos on his web site where he's showing all the steps of the process you hear his two kids crying or making noises while they play in the background, and his wife giving him a hard time. At one point you hear her say something like "...it's been a whole year..." in a very exasperated voice and he has to remind her, "You're being recorded, honey." You can imagine she's been complaining about the project because the whole thing is being built on the guy's kitchen table in what might be essentially a one-room apartment by the looks of it. The toxic MDF routing is done in his bathroom to protect the family and make clean-up easier. This guy was seriously dedicated, or driven, or whatever.

He wrote a book about the project, a DIY manual for repeating his effort and building your own bootstrap CNC mill. I just bought the book and can't wait to read it. Link below.

Beware of Pololu.com

Pololu.com is a bad apple!

UPDATE BELOW

Pololu.com will not issue me a full refund for the order I cancelled before it shipped. I got a call back from them this morning to confirm the cancellation of the order I placed after their normal business hours yesterday, but they then informed me they could not refund 3.5% of the order, the cost of credit card fees.

I was the Manager of Information Systems (and webmaster) at a busy online retailer for a number of years. We did millions of dollars a year in online sales. We never charged any such fee. I was surprised to hear about this fee on the phone, and angry, so it wasn't until after I'd argued with the manager at Pololu.com for a while and hung up that I realized what the problem was. They process the credit card transaction immediately when you place your order.

We never did that where I worked. We only processed the payment when the order was shipped. There are two parts to any credit card transaction. First the transaction is "authorized" at which point the card vendor says you have sufficient credit to fulfill your end of the bargain and the merchant is guaranteed by the credit card vendor that they'll get their money, and that amount is set aside. Then, later, the transaction is "processed" at which time the funds are actually transferred to the merchant's account.

While apparently it's not illegal to process payment before the order is shipped or service is rendered, it is against the terms of service agreements for Visa and MasterCard. I used a Visa. I have no reason to believe this vendor has any explicit exception to the Visa and MasterCard terms of service agreements, so I believe they are in violation. The TOS on the pololu.com web site (and agreement to it incorporated in placing an order) does not obviate their obligation to honor Visa's TOS.

I can appreciate that their ecommerce software, if it's cheap, might make that distinction difficult, or perhaps they simply don't know how to configure it properly, but that's not my problem. They need to change their system, their business practice, and their TOS. Until they do, I do not recommend anyone buy anything from them.

I will be happy to update this post when or if they change their policy and issue me a full refund. I'll also be happy to update this post if they can give me a true and satisfactory explanation for how they can process a payment before shipping and not violate the VISA terms of service.

UPDATE (5-5-2011): Lienna of Pololu.com responded to my follow-up email with this:

Thank you for the additional information. We were not aware of a requirement to delay the charge for an order until the shipping date but are investigating now. In the meantime, we have refunded the remaining $5.44 from your original payment. You may also still use the coupon on your next order. Please contact us again if you have any questions, remaining concerns, or new information for us. Thank you!

So that's responsive at least. I revise my opinion from "find someone else," to, "use them if you can find a part, but keep an eye out and complain to the credit card company if they don't give you a full refund." Hopefully they'll revise their return policy and I can give a more enthusiastic endorsement.

Rotten apple photo courtesy of cooljinny.

Important Lesson About Stepper Motors

Torque! Specifically, holding torque.

Before you order your 5 stepper motors for the RepRap Prusa Mendel, you should read the RepRap wiki about stepper motors.

Here's what tripped me up: I'm using the Wade's Extruder design, which recommends a motor with a holding torque of 5 kg*cm. If you read the above article about stepper motors, you'll know what that means. So, when you go shopping for your Nema 17 stepper motors, you need to make sure they are 24 x 24 mm in size, with a 21 mm shaft length, and a 5 kg-cm holding torque. My mistake was to believe the parts list that came with the printed plastic parts, which was WRONG and recommended a Pololu stepper motor of the wrong size and power. Instead the RIGHT stepper motor is something like the Kysan 1124030 Nema 17 Stepper Motor offered by UltiMachine.  A helpful tool while shopping is the torque conversion tool online.

I believe the seller of the parts was trying to be helpful, but just googled for Nema 17 stepper motor and picked one without realizing the significance.

Project Update: Today I just went nuts online and started ordering everything left to order. I even bought a 5 lb spool of the plastic filament to print with. Obviously, I'm in an optimistic mood. All that's left to buy, then, is the electronics. UltiMachine is currently out of stock on the RAMPS complete pre-assembled kit. I'm going to be doing good just to get the mechanics together, and I don't even want to try the soldering. Total for the day $555.09!