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Old Mar 16, 2010, 05:43 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
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Build Log
CNC Router Build by Complete Noob - Cranky's Phoenix

Hey Folks,

So, a couple of years ago I started dreaming about getting one of those fancy laser cutters I kept hearing about, only to eventually discover that they cost some very serious money, like $10,000 - $25,000! The whole idea of CNC was still very appealing to my tinkerer's heart, so I kept looking around and learned that a CNC router could cut balsa very nicely, and had the added benefit of not needing a mortgage to finance its purchase. Still, a couple of thousand dollars for a turnkey CNC router was still beyond the budget (this is a hobby, after all), and the dream was shelved while I got on with more practical projects. Then one day I discovered John Kleinbauer's site, and the dream came roaring back. Here, if one was to believe Cranky (as he calls himself online), one could build a CNC mill capable of cutting balsa, ply and soft woods for a couple of hundred dollars . I plunked down $36.00 for a set of his plans for the Phoenix, a CNC mill with a 9" x 24" cutting bed, built of medium density fiberboard (MDF), gas pipe, rollerskate bearings and aluminum window channel (!). The plans even came with a bonus set of plans for a unipolar motor driver board, the Perf-X.

John's philosophy is simple; a basic CNC machine doesn't need to cost the moon, and can be assembled by just about anyone with basic shop skills, patience and a few power tools using materials obtainable in most hardware stores and a few (unexpected) specialty shops. That said, getting a homebrew CNC machine working seems to require an eclectic blend of woodworking, mechanical, electronic and software skills that's probably unique. Being an eclectic kind of guy myself, with interests in all of those areas, building my own CNC mill using John's plans seems like destiny .

But first, a disclaimer; anyone interested in following my progress through this journey of discovery, frustration, work-arounds and (hopefully) ultimate success needs to understand that I build slowly, pause frequently, and have an unenviable track record of partially finished projects behind me, so let's not hear any nagging about the pace of construction . Buckle your seat belts and wish me luck!

Steve
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Old Mar 16, 2010, 06:12 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Parts Price List

Since at least part of the appeal of Cranky's designs is the promise of building seemingly complex machines very cheaply using readily available parts, I've decided to keep a running tally of the cost of this project as I go along. I'll come back and edit this post as I buy materials so that a complete summary of my costs should result from my build, and might even be helpful for anyone else contemplating a similar build. Costs are in Canadian dollars unless otherwise indicated.

Parts List and Actual Costs

Plans: US$36.00 (from www.crankorgan.com)
Motors: $25.00 (more on these in a subsequent post)
Driver Board: TBC
Power Supply: TBC
Software: TBC

Materials:
MDF: $20.14 (two 24" x 48" sheets from Home Depot)
Hardware: $22.51 (assorted nuts, bolts and washers from Home Depot)
Angle aluminum: $17.99 (Home Depot)
Threaded rod: $6.38 (1/4 x 20 and 5/16" from Home Depot)
Steel tubing: $25.98 (3/4" x 48" from Home Depot)
Aluminum channel: Free!
Plastics: $18.73
Bearings: $22.35
Paint: $20.58 (big splurge - two Tremclad silver hammered spray bombs from Home Depot)


Grand Total So Far: $215.80

Steve
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Last edited by Steve85; May 07, 2010 at 08:27 PM. Reason: Bought more stuff!
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Old Mar 16, 2010, 06:58 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Stepper Motors

In keeping with the low-budget philosophy of the overall design (and because I'm cheap), I decided against buying new stepper motors from any of the numerous online vendors, and took some advice from some of the pioneers of homebrew CNC mill building by scrounging (cannibalizing, repurposing, salvaging - take your pick!) steppers from old printers. Seems lots of the older dot matrix and laser printers from the '80s and '90s used steppers in their construction, and they're available for free or next to nothing these days. I scrounged two identical 100 oz-inch stepper motors from a pair of Apple LaserWriter II printers, and a third, smaller stepper from an Apple Image Writer printer. I got one printer for free, and the other two cost me a grand total of $25, from which I also scrounged some potentially useful power supplies, micro switches and connectors. Waste not, want not!

Turns out the two bigger steppers were widely used in laser printers, including the HP LaserJet II and III, so these printers are also good donor sources for motors for homebrew machines. I found a data sheet for these motors online, and they're perfect for the Phoenix. I'll use them for the X and Y axes, and use the smaller stepper for the Z axis.

Steve
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Old Mar 17, 2010, 02:31 PM
Build it again, Sam!
Harpye's Avatar
Germany
Joined Oct 2004
4,091 Posts
Hello Steve ... nice built! but one thing I do not understand ... as the inline skater bearings run on the both shafts ... Is there no counter bearing below to take the reactio forces of the engaging bit ... in principle the idea is great - I also had some ideas for a ultracheap setup for a multi axis hot wire cutter ... but as i just have one, I'm not going for this in reallity...
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Old Mar 17, 2010, 10:28 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Harpye,

I haven't actually built the mill yet, I'm just getting started. The picture I posted above comes from Cranky's web site.

There are actually four bearings riding on each pipe, two running along the top of the pipe (visible in the picture above) and another two running along the inside edge of the pipe, at 90 degrees to the two on top. Together they allow only motion along the axis of the cutting bed. Based on my understanding of the design, only the weight of the Y axis and gantry keep the router on the piece being milled. The Phoenix was designed for cutting balsa, so the forces shouldn't be excessive.

I spent some time today laying out the various MDF pieces in preparation for cutting them out tomorrow.

Steve
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Old Mar 18, 2010, 04:03 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
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Today was a glorious spring day in Ottawa, 16 degrees C (maybe 60 degrees F? ), so I moved out on the deck and cut all the MDF pieces for my Phoenix. In keeping with the "common tools" approach, I used a circular saw for this, with good results. I was able to make nice, clean, square cuts using a separate piece of MDF as a fence/guide, held in place with a couple of clamps. I hadn't cut much MDF before this, and was surprised at how much sawdust it produces.

I'm on vacation this week (kids' school break) so I'm trying to get the MDF parts cut, drilled, tapped and painted before I have to go back to work on Monday. For some reason (glue/chemical off-gassing?) MDF seems to give my wife a headache, so I figure the sooner I can get it sealed and painted, the better she'll feel. For now, all the MDF is out in the garage .

Tomorrow, I drill and tap. Pictures to follow!

Steve
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Old Mar 19, 2010, 12:21 AM
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Aluminum Channel

Have you gotten your aluminum channel yet?
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Old Mar 19, 2010, 11:36 AM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
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mlm,

No, not yet. I'm pretty confident I'll be able to find it or something similar.

Steve
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Old Mar 20, 2010, 02:36 AM
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Aluminum channel

If you have any trouble finding it, I'll send you what you need for the cost of shipping from the lower 48. i got it from one of John's "preferred" suppliers quite a while back. It was something like Electronic Utopia. I have gone another route for my cnc experience.
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Last edited by mlmcquiggjr; Mar 20, 2010 at 11:09 PM. Reason: wrong web site
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Old Mar 20, 2010, 09:28 AM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
mlm,

Wow, that's a great offer! Let me look around locally, and if I'm having trouble, I'll drop you a PM. Thanks!

Steve
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Old Mar 22, 2010, 09:38 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
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Here are the results of last week's work. All the MDF parts have been cut out, drilled and tapped, except for the bearing hole and mounting plates for the rail adjusters in the ends of the X axis (the long axis). I've assembled, primed and painted the trolley assembly that carries the Y and Z axes. Before I get some more materials (PVC sheet, bearings and aluminum channel), I can still finish priming and painting the rest of the MDF and work on mounting the X axis motor.

The MDF has been surprisingly easy to work with. It cuts straight, holds a good edge, drills and taps easily. I took a tip from the CNCZone and soaked the tapped holes in CA to harden their threads, and the resulting bolt and tapped hole can be tightened hard without stripping.

I'm about to order some bearings from VXB, 16 roller blade bearings ($14.95) and three 1/4" ID flanged bearings ($4.95 each), and pick up some PVC from Home Depot to get to work on the trolley bearing rails. In the meantime, I'll be finishing up the MDF parts.

Steve
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Old Apr 01, 2010, 05:48 AM
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Looks good! Any idea what you're going to use for a controller board?
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Old Apr 01, 2010, 03:52 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Hey RC-A,

That's an excellent question! It's preoccupied me for a while . Cranky's plans for the Phoenix come with a bonus plan for a three-axis controller board he calls the Perf-X. It's based on the L297 controller chip and discrete transistors driving the motor coils, built on perfboard. Like the Phoenix itself, it is a simple, straightforward design. For a while, I thought I would build my own three axis board using L297 and L298 chips, with an opto-isolated parallel port, and even went so far as to lay it out on perfboard and price the parts. Turns out the parts alone would have cost between $60-$70. As I did more research, I decided I would rather not fool around with large, expensive ballast resistors, and looked for a chopper board. For the money, I think I'm going to buy the Hobby CNC PRO 4-axis chopper board kit, since it's about the same cost as the parts for my home-brew board, doesn't need ballast resistors, has a fourth axis for future growth, and is built on a professionally etched PCB.

http://www.hobbycnc.com/products/hob...er-board-kits/

I haven't ordered it yet, but that's where I'm leaning.

Steve
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Old Apr 04, 2010, 09:05 PM
cousin Dave
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Huntsville, Alabama
Joined Nov 2002
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The HobbycncPro board is a good choice. I built their foam cutter Pro board and a friend built the same one you're going to build. Get ready for a big soldering session. More soldering then you've done in a lifetime. It's fun if you like that sort of thing. There are hundreds of parts and Hobbycnc does a great job with the packaging and directions.
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Old Apr 06, 2010, 11:33 AM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
GG,

Thanks for the heads-up on the HobbyCNC board. I'm pretty good at soldering, but by the sound of it I'll be even better once I'm done!

Steve
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