CNC-2116 - Up and running, sort of (2015-03-21)

[Yvan256]

After seeing crashwg's CNC machine and especially the results he got when he milled that 4" wooden token, I've decided to build my own CNC machine too. Seeing dexxy's MechMate cutting panels for his Neon Copy was also inspiring.

For the last five years or so,  I've collected easy-to-do ideas about linear slides, motor couplings, anti-backlash nuts, etc. Just like an arcade cabinet, there's a lot of topics to cover and different ideas depending on the available budget and tools.

My problem is that I have many projects on hold because I can easily design things in Sketchup but I have a hard time actually building them. It's easy to make a Neo-Geo side panel in Sketchup, it's another thing to be able to cut it properly with all those angles and curves. Having a small CNC would make the job of cutting the required parts so much easier. I'm not planning on doing RCBs (routed circuit boards), so even a so-called low-precision machine would be just fine with me.

So, I'm trying to build a really simple, very extremely low-cost 3-axis CNC milling machine: CNC256.

• Cutting area of 24 x 20 x 2 inches (60.96 x 50.8 x 5.08 cm - I know Canada is supposed to be metric, but being so close to the USA, almost everything from wood to bolts is almost always in feet and inches). I could have gone for 24 x 24, but the machine is already going to be wide enough as it is. Big enough for desktop arcade cabinets and big enough for the panels of a future project, which at last count needed over 50 precisely-cut panels.
• I've bought four stepper motors (1.8 degrees, 24v) at an electronics surplus store for around 8$CAD each, I think. It's been too long, I can't even remember which year I bought them. (update: I contacted the store, they were only 4$ each) Why four? At that price, and given that it's a surplus store, I wanted to have at least one backup motor.
• I'm making my own stepper controllers to reduce the cost. So far I've got (good) preliminary results with an Atmel ATtiny85 and four TIP120 for my first tests. I plan to use one ATtiny84 (the ATtiny85 doesn't have enough pins to control the motor and receive signals) and one ULN2803 (two lines wired in parallel for each motor winding to allow 1A per chip) for a total cost of around 4$CAD per axis (plus taxes and shipping, required pcboard that I'll make myself, etc). It won't have extra-smooth motion or power-saving features, but at around 15$CAD to control all three motors this is a hard deal to beat. The cheapest controller for 3 motors seem to be around 35$ on eBay which is more than twice the cost of my controllers. And by building it myself, and with a microcontroller, I control and know everything from A to Z, and I'll be able to update the software later if I want to (microstepping, etc).
• For the "CNC computer" itself, the thing that drives the motor controllers, I plan on using Grbl instead of an actual x86 computer. With the external clock, power supply, etc it's going to cost about 10$ for the "computer". I'll still need a way to transfer g-code files to it... probably via an SD card, a small LCD display, small joystick and buttons (I plan on using arcade parts for that). The goal is to have an autonomous machine that doesn't require an external computer connected to it.
• Inverted V-groove skate bearings linear slides (idea by larry104) - I dropped that idea because the nuts grind on the aluminium angle and it's near impossible to adjust them properly.
• Fake V-groove skate bearings on aluminium angle, idea taken from Ro-Bot-X's Weblog, who modified an idea from TinHead, who modified the idea from the blackToe... The plan is to go with the Route-X design, change the aluminium angle when it wears out (if it wears out enough to need replacing that is, after all I'm not planning on using the machine more than a few hours per week) and upgrade to real v-groove bearings later and possibly steel angle much later on. That should allow easy upgrades, one at a time to lower costs, and without needing to re-cut any panel.
• For the motion, I'm going with regular threaded rod (low-cost) with home-made HDPE nuts. My father has donated enough HDPE blocks to make 12 nuts - three for the machine, nine backups!)
• I planned on using the Dremel tool I already have for routing, but regular 1/4" routing bit won't fit and according to most people a Dremel is just too under-powered for such a job. Seeing the videos on YouTube vs proper trimmers/routers, I have to agree.
• I'm recycling a lot of particle board panels from older/abandoned/failed projects. So far I had enough to make the whole Y and Z axis.
• I also plan on adding a mini Shop-Vac with a home-made cyclone dust separator similar to that one. My father has both a full-size and mini shop-vac so I'll be able to compare the two and see if the mini is enough for the job.

Bill of materials (prices in Canadian dollars with taxes):

• 32 skate bearings (ABEC5): 30$
• Four stepper motors (NEMA 23, 24v, 1.8 degree per step): 16$ (three for the machine, one backup)
• Two 8 feet long, 1/2 inch wide, 1/8 inch thick aluminium angles: 36$
• Particle boards: 0$ (already had those, recycled from older projects)
• Three Motor controllers: 13$ (not bought yet)
• Threaded rod: 10$ (not bought yet)
• Nylon nuts: 0$ (home-made, HDPE plastic blocks donated by my father, not done yet)
• Various bolts, nuts, washers: around 10$
• Power supply for the microcontrollers and motors: unknown (not bought yet)
• Computer: unknown (not bought yet - I know the ATmega328 costs 4$, but the other parts are a bit unknown right now)
• Shop-Vac mini: 40$ when on sale (not bought yet)
• Cyclone system of the shop-vac: 2$ (plastic pipe connectors, one angled and one straight. I plan on finding the plastic bucket and tubing for free)
• Total so far/planned: around 166$ (rounded up)

Please note that since some parts came from surplus stores or some parts are different, I used average prices for those parts. I'm also going to need more wood panels to complete the whole thing.

I still need to get a small trim router, but I'm setting the budget for that at 100$CAD maximum. I'll be checking for units on sale.

Attached is a cutting size capability comparison between standard size/popular kits sold on the internet (the two models of blueChick, the two models of blackToe and the Mechmate).

[drventure]

Looking forward to this thread. I've wanted to do the same thing, but don't really have space.

Maybe after you're build, I'll find space 

[Yvan256]

Some new parts arrived today. I already had 16 bearings, but due to the design I'll need more. Local stores only sell extremely high-end skate bearings, so my brother brought me this pack of 16 bearings when he visited. Adds 14.80$CAD to the build cost, or 0.93$CAD per bearing. Still cheap to replace when they fail.

Thanks Daniel!

[syph007]

Glad to see you start this thread.  Im in Canada too and have been wondering how hard sourcing parts will be.   Can I ask where you found your steppers?

[Yvan256]

Glad to see you start this thread.  Im in Canada too and have been wondering how hard sourcing parts will be.   Can I ask where you found your steppers?

I got my steppers at Accès Électronique. They have four stores, all in the Quebec province. Never mind their website, their stores usually have a much bigger selection. Since it's a surplus store, the selection varies all the time.

The inventory number for my motors is 51925. I added two photos to my first post. For an idea of scale, the square part of the motor mount is 56mm wide/tall.

I emailed them to ask if they had any left, and the price. They don't have this motor for sale anymore which isn't surprising since they're a surplus store (am I glad I bought four), but the price was only 4$ each. I'm sure most of their stores currently have similar motors at around the same price.

If I had known how good they were, I would have bought a dozen.

Tip: try to get 12v motors, you'll have less trouble finding a power supply for your motors... i.e.  power supply from old PCs.

[Yvan256]

Looking forward to this thread. I've wanted to do the same thing, but don't really have space.

Maybe after you're build, I'll find space  

A small CNC that can cut 10x10 inches panels wouldn't be much bigger than a big desktop laser printer.

[Yvan256]

Here's a small preview of the design, the X and Z axis are pretty much done and I only need to finalize some details about the Y axis. The goal is to keep it simple to cut and build to minimize the errors and alignment problems.

Yes, the bearings will be grinding the aluminium angles, but since I will only be using the machine a few hours every month at most, it shouldn't become a problem for a relatively long time. This design also allows easy replacement of the dual skate bearings with v-groove bearings without having to re-cut any panel.

[nox771]

Glad to see you start this thread.  Im in Canada too and have been wondering how hard sourcing parts will be.   Can I ask where you found your steppers?

If local sources don't work for you there are a couple places I know of:

http://www.kelinginc.net/index.html  - I got some heavy duty steppers from this place (I'm building an aluminum extrusion CNC).  They have the drive electronics also.  Good place for heavy duty steppers - not cheap, but durable.

http://www.allelectronics.com/make-a-store/category/400/Motors/1.html  - I ran across this place recently, they are always sending me mail (I'm in the US btw), but I never really checked them out.  Finally one day I did - out of their whole site the motor section looked most interesting to me.  Turns out they have a lot of small motors, and quite inexpensive also.  Some look pretty good too, like these:
http://www.allelectronics.com/make-a-store/item/SMT-119/4-LEAD-1.8-DEG-STEPPER-MOTOR/1.html
http://www.allelectronics.com/make-a-store/item/SMT-363/4-WIRE-STEPPER-MOTOR/1.html
I haven't bought from these guys yet, but if I were to make a tabletop sized CNC I might try them out.

[Yvan256]

Some look pretty good too, like these:
http://www.allelectronics.com/make-a-store/item/SMT-119/4-LEAD-1.8-DEG-STEPPER-MOTOR/1.html
http://www.allelectronics.com/make-a-store/item/SMT-363/4-WIRE-STEPPER-MOTOR/1.html

Just to simplify your life, unless you're buying the stepper drivers, get motors with 5 or 6 wires. The 4-wires motors need a completely different driving method. And as I mentioned above, try to get 5v or 12v motors so you can easily find power supplies for them.

[Yvan256]

Trying to optimize the panels on a standard sheet of 4x8' while also trying to minimize the number of cuts required. Panels are colored for easier comprehension. Also shown is the aluminium angles and 3' threaded rod.

[crashwg]

Looking good.  My only concern would be the wear on the aluminum angles but you've already acknowledged that will be "wear" parts and need to be replaced.  Also, I didn't see any mention of bearings for the lead screws.

[Yvan256]

Looking good.  My only concern would be the wear on the aluminum angles but you've already acknowledged that will be "wear" parts and need to be replaced.  Also, I didn't see any mention of bearings for the lead screws.

The bearing setup shown above is only because it makes the whole thing a lot easier to plan and assemble. However, I'm currently testing the same bearings+angle method used on your machine and a lot of other CNCs. It's an extremely popular method but I'm searching for the easiest, most cost-effective way of doing it. My aluminium angle is only 1/2" so I would need to buy yet another 8' length only for the bearing supports. It's not exactly cheap and I would only use a small fraction of it. Using square tubing would make assembly easier, but I also don't have that.

I do have six smaller bearings that fit my 1/4 threaded rods. I can't remember where I got them, but they were in my box of parts that I've accumulated for the last five years with the goal of building this CNC.

What trimmer or router are you using on your machine?

[crashwg]

What trimmer or router are you using on your machine?

THIS ONE  It's a little bigger than most people use on these home made CNC machines but another builder of the "book machine" did it and was happy with the results so I bought one too.  I upgraded the collet system on the router though to these precision ones. Which allowed me to hold smaller bits which was essential for the mini coin doors.  THIS is where I purchased my carbide end mills by the way.  Prices are amazing, product is awesome.  Only downfall is the $75 minimum order. Unfortunately or fortunately depending on how you look at it, it's pretty easy to meet the minimum with carbide even at their low prices.

[Yvan256]

This one. It's a little bigger than most people use on these home made CNC machines but another builder of the "book machine" did it and was happy with the results so I bought one too.

Hitachi M12VC, 3.3 kilograms... it's quite heavy, I hope your machine isn't flexing in the middle?  

From what I've read, most people seem to be happy with the Bosch Colt, which only weight 1.5 kilograms. Then again, from what I've read, the M12VC is also the quietest router in that price range.

[Yvan256]

I just got a Hitachi M12VC from my parents! The cost of this project just got a lot lower!  

Thank you both!

This thing is really quiet at 8000 RPMs! 

[mountain]

Sweet! That is the router I use on my CNC. Very quiet, cheap, and easy to refurb.

[Yvan256]

Sweet! That is the router I use on my CNC. Very quiet, cheap, and easy to refurb.

Not sure how much is costs in the USA but here in Canada it sells for 200$CAD, it was on sale for 140$CAD just before Christmas. Not what I'd call "cheap", however I don't know how much similar routers from other companies cost.


Also, I'll have to change the name of my machine since "CNC256" returns too many results. Maybe "CNC5161", which is the cutting envelope converted to centimeters. Currently at only 10 results on Google.

[Yvan256]

Looking forward to this thread. I've wanted to do the same thing, but don't really have space.

Maybe after you're build, I'll find space 

Would you have enough space for a small desktop CNC?

I'm working on my own design with a 6x4x3 envelope and removable tools. So far I'm planning on those four tools: multicolor pen plotter, mill for PCBs and MDF, hot wire foam cutter, hot glue 3D printer. And probably ABS/PLA 3d printer tool later, unless I build a Tantillus first.

[Yvan256]

Okay, so I backtracked a bit on what I planned to do for a CNC.

First of all, the Hitachi M12VC is a very nice router, however it's also very heavy at least compared to a small Dremel. That means the whole machine has to be stronger to hold it, not bend in the middle, etc. I also don't have the room for the size of CNC machine I initially planned to make.

So I did a few tests on MDF and particle boards with my Dremel 395 using a small 1/16" carbide bit made to cut PCB panels and the results are very good, although you need to cut slowly and not very deeply for good results. I'm not making a commercial production machine here, I only want something to help me cut wood and plastic for my various personal projects. Dremel also makes 1/8", 3/16" and 1/4" routing bits (Dremel #650, #652 and #654).

So I went looking for smaller CNC machines such as the Mantis I mentioned above, with the idea of using my Dremel on it. But then I kept making the design bigger to be able to cut some parts for MVS-99-6 and other small projects, then a bit bigger for some other parts, etc. In the end I had something as big as my laser printer. Enough is enough!

So, with that in mind, I went back to the design of my CNC machine. Small enough but still capable of doing what I wanted to do in the first place!

The goals for the "new" machine are:
- make it with the parts and materials I already have
- keep the design simple so it's easy to make and adjust
- use skate bearings to keep costs down but in a configuration* that makes it possible to upgrade to real V-groove bearings at a later date
- use cheaper step motors** in order to save the NEMA23 motors for a possible future bigger, stronger and faster CNC machine which will use the M12VC.
- small enough to be carried by a single person
- small enough to fit on a desk or table
- small enough to fit in the back seat of a car
- and last but not least, I want to be able to cut bigger panels*** in multiple passes

* I will use the same skate bearing configuration as TinHead but with a single washer in the middle and ridding them on the edge of the 1/8" aluminium angle. It works surprisingly well and from what I've read the aluminium will deform with use but only up to a point. Again, hobby CNC usage, not commercial. I don't think I'll need to replace the aluminium angles any time soon.

** Yes I know those motors are only 24 steps, but with 1/4-20 threaded rods 5/16-18 threaded rods the resolution will not be a problem. That makes 480 432 steps per inch, or a theoretical 0.002083 0.002315 inch per step. For reference, 1/32" is 0.03125". I changed from 1/4 to 5/16 threaded rods because then I can use a regular skate bearings to hold the rods in place. And 18 threads per inch instead of 20 also means it's going to be about 10% faster.

*** Now, the "able to cut bigger panels in multiple passes" idea requires some explanation. By "bigger" I mean panels bigger than what the machine can cut in a single pass. If a picture is worth a thousand words, how much is an animation worth? See the first attached image (click on it to see the animation). I cut the big panel into three equal parts to make it easier to see what's happening between each frame. Bender will probably remember why I want to be able to cut bigger panels. No, that project is not dead. ;-)


As an added bonus, those indexing pins will allow me to cut both sides of a panel (cut, flip over, cut), so having pockets or angles on both sides of a part won't be a problem.

The first frame shows the machine by itself, with its cutting area of 18 inches wide (left to right) by 10 inches deep (front to back).
The second frame shows the machine with its back and front extensions and a 18x30 inches board.
The third and fourth frames show how I will move the board between each step, held in position by four indexing pins in the table of the machine.

So to cut a "3x panel", I put it in position #1, let the machine cut the first third of the panel, move the board into position #2, let the machine cut the second third of the panel and then move the board into position #3 and let the machine cut the last third of the panel.

The back and front extensions will have holes to bolt them on the CNC machine when in use and hinges so I can fold them flat for transport or storage.

The second image is the machine with five parts from my MVS-99-6 project, just to test things out with the cutting area of a single panel.

[Yvan256]

After the usual Sketchup plans, here's the next step for most projects around here: a pile of cut panels.

Low-quality photo courtesy of my Nintendo DSi.

[Yvan256]

This project is progressing slowly, but at least it's moving forward. Sorry about the non-metric measurements, but almost all the building materials here in Canada use the imperial system so it's easier to just use imperial everywhere. And even when metric hardware is available, it's usually nearly twice as expensive as imperial. With that said, let's get back to the topic.

I started cutting the router mount for the Hitachi M12VC yesterday. In the first photo, you can see that I cut 5x5" squares out of 5/8" MDF. Then, I drew lines to find the center. I used two methods at once to be certain I was in the middle. First I drew four lines, using a block a bit shorter than 2.5". That made parallel lines with a little square right in the middle of my 5x5" part. Then I drew the usual "X" lines from the corners that cross in the middle. Since the "X" happened to be right in the middle of the little square, I was 100% sure that I was centered. Or at least that I was completely off-center by exactly the same amount, twice, on two parts. 

Then I carefully punched the middle with a very small and sharp nail and drilled a progressively bigger hole, in 1/16" increments, to make sure it was always centered. Once I got to 1/4", I switched to a 7/8" hole saw bit to make big round holes. This bit makes holes that are exactly the same diameter as a roller skate bearing (as shown in one of my first posts of this project), it's a really tight fit.

In the second photo, you can see how I used a 1/4" router bit on a drill press with a jig with two skate bearings and rotated the 5x5" plate many, many times, probably around 1/32" depth on each pass, to drill a 3.27" diameter hole. A drill press doesn't turn nearly as fast as a router and has a much bigger play at the bit, but at least it's easy to increment the cutting depth.

Why go to such lengths and not use a circle cutting add-on with the router I already have? Because the only one I had access to couldn't make a hole that small, not to mention that the M12VC is a fixed base plate router and incrementing the cutting depth at each pass would have been troublesome. And the smallest hole I can make with my Dremel router attachment is around 3.5".

The third photo is the router inside the two mounting plates. There's still work to be done on those plates, but at least the router fits snugly inside them.

[rbarr110]

Good luck with the build, they are very fun machines to play with.  It took me about 2 years of slowing collecting parts and building to get mine done.  Mine has been FULLY functional for close to a year now and am just starting to really put it to work.  Once I started pricing putting one together, there wasnt much difference from a smaller machine to the larger...so I went larger, a 4'x5' cutting area.
A quick video of my first movement.


Looking at your pricing list, where did you find cheap $13 motor controllers? Most of the controllers I find are anywhere from about $40 - $130 depending on what you need.   I personally went with the Gecko G540 for the built in driver board and 4 motor controllers...and amcontrolling the Nema 23's.

[Yvan256]

Good luck with the build, they are very fun machines to play with.  It took me about 2 years of slowing collecting parts and building to get mine done.  Mine has been FULLY functional for close to a year now and am just starting to really put it to work.

I've been reading and collecting parts for the last 5 years, so I know what you mean. From what I've read, I'm guessing the learning curve of all the necessary software is the hardest part. I've already got half a dozen projects planned for my machine, can't wait to have some fun too! 

Once I started pricing putting one together, there wasnt much difference from a smaller machine to the larger...so I went larger, a 4'x5' cutting area.

I wish I had the budget and the room for such a huge machine. Unfortunately I need something small enough to be mobile, to carry around from my apartment to my father's shop or to a friend's house.

Looking at your pricing list, where did you find cheap $13 motor controllers? Most of the controllers I find are anywhere from about $40 - $130 depending on what you need.   I personally went with the Gecko G540 for the built in driver board and 4 motor controllers...and amcontrolling the Nema 23's.

I'm building my own controllers from ATtiny microcontrollers and IRLZ14 logic level mosfets. So far it works fine with the can-style, 12V stepper motors I got for 4$CAD each.

[selfie]

Nice work! The pass through cutting of the larger sheets is a great idea, once you get your head around the programming it's really easy.

I'm in the market for a new CNC router too but mine gets used for paid work 8 hours per day so my budget is a bit higher 

Do you have plans for software?

To run codes I use Mach3 http://www.machsupport.com/
and Vcarve to program codes  http://www.vectric.com/

A tip when you get around to you HDPE nuts. The link says to cool the HDPE in water, this gains you nothing over letting it cool naturally but increases the chance of creating backlash in the nuts with the unnecessary movement.  I would secure the threaded rod in place and heat the rod as described but instead of quenching in water I would cool the rod in the same method as heating.

[Yvan256]

Nice work! The pass through cutting of the larger sheets is a great idea, once you get your head around the programming it's really easy.

I'm in the market for a new CNC router too but mine gets used for paid work 8 hours per day so my budget is a bit higher 

I've read good things about spindles, especially water-cooled ones. Not sure if it's in your budget range, but it's really worth looking into from all the comments I've read about these.

Do you have plans for software?

To run codes I use Mach3 http://www.machsupport.com/
and Vcarve to program codes  http://www.vectric.com/

I have zero budget as far as software goes. I was planning on designing things in Sketchup, then export/convert to another format used by LinuxCNC. Going with Sketchup just because I'm used to it and it's easy to make parts, group them, move them around in a 3D project, etc. I'm talking mainly about arcade parts and arcade panels here, however, not 3D signs with text.

A tip when you get around to you HDPE nuts. The link says to cool the HDPE in water, this gains you nothing over letting it cool naturally but increases the chance of creating backlash in the nuts with the unnecessary movement.  I would secure the threaded rod in place and heat the rod as described but instead of quenching in water I would cool the rod in the same method as heating.

I was planning on using two blocks with holes to hold the threaded rod level and to a precise height, and use two clamps, one on each side of the HDPE halves sandwich. All that would be left to do is heat the threaded rod, the rest would be "automated", so to speak. Less risk of movement. The stuff I have is much tougher than HDPE though, I think it's Delrin or something. And while I'm at it, I'll be making more than three blocks, to have ready-to-use spares.

[selfie]

Delrin will last MUCH longer than HDPE and won't be any harder to form.

A water cooled spindle would be nice as they are a lot quieter than the air cooled ones but they are too hard too get in my power range ~9HP

[Yvan256]

Another small step done today. I drilled more holes to attach the back and front panels to the bottom plate of the base of the machine. I didn't have enough bolts for all the holes, however it's quite sturdy even with four bolts and the top panel missing. The bolts are not countersunk because this is the underside of the machine.

I can't wait to complete the base of this thing, I'd like to have at least one axis completed before the end of the month!

The six panels, seen on top of the reversed base, will go underneath the top panel of the base to reinforce it from back to front. There is 10 panels in the base of the machine and a total of around about 18~20 panels for the whole machine. So once the base is complete, the machine will be about 50% complete. Or only 33% complete if we go with the three axis needed, but from what I have read the base is usually the longest part to build.

And yes, that is a skate bearing you see in the front. Two bearings and four nuts will hold a 5/16"-18TPI threaded rod in place.

Once again, the low-quality photo is courtesy of my Nintendo DSi.

[Yvan256]

A shop vac is a very crucial part of a CNC machine, because of all the dust made while cutting.

So, imagine my surprise when last wednesday (my birthday), I got this little thing. Thanks Daniel!

This Shop Vac may be small, but boy is it loud! But it's also very strong, just like a regular-sized one!

Now all I have to do is built a little dust cyclone to go with it!

The name seems vaguely familiar for some reason... What's even funnier is that the colors are the same. 

edit: it doesn't matter if the capacity of the Shop-Vac itself is small, because the dust will be collected by the... eh... dust collector. 

[Nephasth]

I got that same mini vac for a wedding present. It's great. I can hook it up to my router table and really keep the dust down, love it for sucking up debris when doing engine work as well.

[Yvan256]

Does anyone know where to buy a Black and Decker RTX in Canada for a reasonable price? I really don't think my machine will be able to support the weight of the Hitachi M12VC and the Dremel is just a bit underpowered. I mean, it would work but I'll only be able to cut about 1/32" deep at a time. To cut a 5/8" thick panel would take 20 passes. It's still better than cutting by hand for complex shapes, but that's quite slow.

The RTX has almost twice the amps of the Dremel so I guess it would be a good compromise.

The problem is, the RTX is listed at 30~35$USD on USA websites (Target, Wal-Mart, Amazon) but I've only seen it on Amazon.ca for 52~70$. 

[Yvan256]

Another small update. I had problems with the particle boards, so I've switched to MDF. I'm also unsure about the whole "make bigger panels with indexing pins", so I've changed the size of the machine back to one that would allow me to cut the panels for my MVS-99-6 desktop arcade machine.

Here's the progress on the Z axis. It's a variation on TinHead's design from his Valkyrie CNC, made to reduce the width of the whole carriage. By using a "T" configuration for the front plate/rails assembly, instead of putting the rails on the side of the front plate, I was able to keep the whole thing at only 3.5 inches wide.

It's missing four mounting holes on the front plate, a top plate with the motor and the threaded rod and nut, but this is more or less complete for the Z axis. It's also the X axis carriage. Some of the holes for the bolts+bearings assemblies are oblong, to allow for precise alignement with the rails.

Included is three photos, showing the two parts alone and assembled.

[Bengaz]

You lot should work for NASA!!!

[menace]

You (and crashwg) have inspired me into my next project  .  I like how your linear bearings look compared to the standard DIY variety.  Did you regain much work space doing that versus the >< arrangement?  I'm trying to make the machine size small but maximize the work space so anything that gives me more travel is desirable.  I understand there is about a 4" loss in the x and y due to how the frame and router line up and my ultimate goal is to crank out some bartops.  So a table of 24" x 48" works out to a working space of 20" x 40"  that seem about right?

With regards to you stepper drivers--was this a circuit you just knew how to build or were you following instructions from someplace.  It seems to me the electronics are the most expensive part of the build and I'm hoping to trim a few bucks from the budget.

Failing building my own, any thoughts on this combo:  http://www.ebay.ca/itm/200806516142?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Keep up the good work!

[Yvan256]

You (and crashwg) have inspired me into my next project  .

First off, I'm glad to see yet another arcade builder embark on the CNC quest! If anything, we'll shortly be able to see more arcade-related CNC cutting videos on YouTube, I'm tired of watching 3D plates and router mounts videos. 

I like how your linear bearings look compared to the standard DIY variety.  Did you regain much work space doing that versus the >< arrangement?

The space gained is probably not that much, all things considered. Also, after playing with the Z-axis manually, I have to agree with tinhead about the aluminium angle being too soft for this configuration. His latest machine still uses a weird setup but it seems to be much better, at least according to him.

I still had to try using the edge of aluminium angle just to see how bad it was, because it makes the whole thing a lot easier to build. It might end up better with real v-groove bearings. However, with my fake v-groove bearings, this setup it didn't last very long because after moving it a few dozen times manually it already had a small play in the setup. I've also read that once the aluminium edges are compressed that it's fine after that, but you do need to "break in" the edges" with a program to run your machine on all three axis from zero to max, to wear/compress them evenly on the whole surface. For that reason, I went back (again) to the tried-and-tested setup used by people all around the world. I only have two six inches bearing assemblies made so far, but it runs a lot smoother than the edge rolling setup. And in that configuration, the wearing of the aluminium angle will be minimal since the bearing rolls parallel to the surface of the angle.

I'm trying to make the machine size small but maximize the work space so anything that gives me more travel is desirable.  I understand there is about a 4" loss in the x and y due to how the frame and router line up and my ultimate goal is to crank out some bartops.  So a table of 24" x 48" works out to a working space of 20" x 40"  that seem about right?

A 24x48" table with a working space of around 20x40" sounds about right to me if your Z axis assembly is around 4" wide and your X axis assembly is about 8" deep. However, those are rough estimates, I'd need to see your plans to make sure.

You will lose a lot in the Y axis because of the X axis assembly. But you can't make this assembly too narrow because you'll lose structural strength. As for losing working space in the X axis, you can work around that a bit by making your Y rail go "outside the box". See how the Y rail of the blackFoot is assembled (first photo)?

The best thing would be to make the plans in Sketchup or similar, down to the last detail. That way you can really squeeze out every last 1/16" possible and know in advance what's needed, the dimensions of each part, etc.

With regards to you stepper drivers--was this a circuit you just knew how to build or were you following instructions from someplace.  It seems to me the electronics are the most expensive part of the build and I'm hoping to trim a few bucks from the budget.

It's more or less an already known circuit to which I'm going to try and add an Atmel microcontroller to lower the cost instead of using a pre-built controller chip. The IRLZ14 transistors will do the heavy lifting and the microcontroller will do the logic between the commands of the computer and the transistors. However, it's going to be crude at best with no power control or microstepping, so it's more of a temporary solution. And there is now very cheap TB6560 controllers on eBay, so I'm probably not even going to bother making my own at all. Since surplus motors are 24v, I'll have to try and get three used 24v laptop power supplies from the local recycling center. I hope I'll be lucky enough to find three power supplies of the same model.

Failing building my own, any thoughts on this combo:  http://www.ebay.ca/itm/200806516142?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Actually, for all the included stuff, it's a pretty good price. Those motors will probably be more than enough, the controller is the one I have on my watch list and even the power supply and parallel cable are included. Frankly, if I had the money I'd be tempted to order one of those kits myself!

What do you plan to use for the milling tool? Dremel 4000? Bosch Colt? Dewalt 611? Hitachi M12VC? The weight and power of your tool will decide of a lot of factors for your machine, i.e. the structural strength needed, etc. I'm still new at this, but my one tip would be to never underestimate structural flex caused by weight.

[Yvan256]

As you can read from my reply above, I've decided to switch back to the usual bearing assembly used by hundreds if not thousands of people worldwide. In building the Z-axis to test things out, I found out that the aluminium angle edges wear out too fast and too unevenly. Real v-groove bearings and breaking in the machine would probably work but I don't have nearly 150$CAD for bearings alone.

So, yesterday I built the first two bearing assemblies, six inches long each. I did have access to my father's drill press, so the holes for the bolts are at a perfect 90 degrees. The holes were tapped manually but with a cut bolt inside the drill press, so the threads are at a perfect 90 degrees too.

These assemblies roll extremely smoothly on the sides of the aluminium angle. I would also not be afraid to put the weight of the M12VC on these, as opposed to my previous setup.

Sorry about the uneven lighting in the animation, the DSi isn't exactly a high-end camera. 

note: the aluminium angles do not touch, it's an optical illusion because of the angle of the camera. There's about 1/8" space between the "tops" of the angles.

[Ryglore]

Oh man. I must catch up on this thread later. So much goodness to read since I've come back!

[menace]

Thanks for the feedback!  I started cutting mdf this weekend and managed to scrounge enough old roller blades from kijiji to come up with 30 5/16" bearings--total cost was about $10 for those   I'm going to pull the trigger on the electronics and motor bundle as I have yet to find a place to get everything together locally.  My next stumbling block is the cross dowels--they are 1.39 ea. at home deport and I can't believe thats the best price for these--The build your own cnc guy sells them for .50 so I'm sure they can be sourced somewhere.

As far as the router goes, I plan on using my rotozip with its handles removed.  It's 23,000 rpm and screams like a banshee but I think I can dial that back a little.   It cuts mdf so fast that if you don't keep it moving it'll start to burn

 I should really start a build thread and stop hi jacking yours 

[Yvan256]

Thanks for the feedback!  I started cutting mdf this weekend and managed to scrounge enough old roller blades from kijiji to come up with 30 5/16" bearings--total cost was about $10 for those   I'm going to pull the trigger on the electronics and motor bundle as I have yet to find a place to get everything together locally.  My next stumbling block is the cross dowels--they are 1.39 ea. at home deport and I can't believe thats the best price for these--The build your own cnc guy sells them for .50 so I'm sure they can be sourced somewhere.

As far as the router goes, I plan on using my rotozip with its handles removed.  It's 23,000 rpm and screams like a banshee but I think I can dial that back a little.   It cuts mdf so fast that if you don't keep it moving it'll start to burn

 I should really start a build thread and stop hi jacking yours 

Good idea for the bearings, I bought mine new, didn't think about getting old roller blades at flea markets. I agree about the electronics+motors+power supply kit, if you can afford it.

As for the cross-dowels, I haven't found any place that even know what these are, let alone a place to buy them. So I went with the "cheapo" idea instead.

I'm guessing you'll need to be careful with the cutting speeds if the rotozip can burn the material. Or maybe you're trying to cut too deep in one pass?

Please do start your own thread if you have something to show, another CNC building thread would be nice to read! 

[menace]

Not sure if you have lee valley near you..

http://www.leevalley.com/en/hardware/page.aspx?p=44238&cat=3,41306,45375

Not as cheap as el cheapo but not 1.39 either

[Yvan256]

Not sure if you have lee valley near you..

http://www.leevalley.com/en/hardware/page.aspx?p=44238&cat=3,41306,45375

Not as cheap as el cheapo but not 1.39 either

Nope, closest one is Ottawa. Then again that means no duty or brokerage fees either.

Since I'm using 5/8" inch thick particle board/MDF, I would need the 16mm long cross-dowels, which don't have a centered hole. I'm not even sure why they make them that way.

Even in 100's quantities, it's still at least 4 to 5 times more expensive even without shipping compared to simply using a washer+nut. Ugly or not, if it costs about 5 cents for a nut and 1 cent for a washer, it means around 6.50$ for 100 nuts+washers bought locally vs around 45$ for 100 cross-dowels shipped, if it only costs 10$ for shipping. Given the weight of 100 of steel cross-dowels, I doubt it would be as low as 10$.

The price difference is almost enough to buy that TB6560 controller on eBay, since a lot of Chinese vendors offer free shipping.

Thanks for the link though, I might have future projects that would be better off with cross-dowels for a neater finish.