$20 CNC Machine

Step 4 X,Y,Z tables for your brunch

Alright now here comes the most time consuming part
making the tables for the slides but once they are made it really feels like the project
is taking off.

Required Materials

Quantity Type Cost

1 6"x12"x1/4" Acrylic sheet Scrap

1 6"x10"1/4" Acrylic sheet Scrap

1 5 1/2"x5"x1/4" Acrylic sheet Scrap

15 1 1/2"x1 3/4"x1/2" Acrylic sheet Scrap

Now what you are going to want to do is stack 4 pieces of the 1 1/2"x1 3/4"x1/2"
and drill dead center with a 3/8 drill bit

After you have done so feed 2 pieces on each rod
and line them up and place your sheet on top and flip it over now glue.

Repeat for each axis

For your Y axis

now would be a good time to drill your holes so you can mount things you wish to cut.

Comments

[daveand5]

i think you would be much better off using UMHW for the bearing marterial, its nearly indestructible and can be found as common place as the acrylic, and a bonus is it doesnt get brittle like acrylic.

[Techbuilder]

I completely agree and I assume you mean UHMW? Like I stated before people here forget the fact that I was trying to do this for 20 dollars and that was my main goal. The place where I buy my scrap pieces of plastic don't have UHMW OR HDPE in the scrap been just acrylic and expanded pvc also abs on occasion, If they did I would of went for that in a heart beat but they simply just didn't have it in the scrap bin and had I of ordered a piece cut to size it would of been well over 20 bucks.
UHMW is also almost twice the price of HDPE which for the person with the shallow pockets would really not appreciate.

I really do like everyone throwing out there ideas because this was an instructablefor someone to get an idea and develop my design into something that suits them or maybe if they want to spend a little more you could upgrade the material or purchase nice steppers. Whatever it maybe I wanted to show that 20 bucks and lots of searching time could make you something cool and possibly useful if you put the time into building it correctly.

[wii552]

could wood be used instead of plastic for most things?

[NewB007]

Wood expands and contracts with humidity (and non-uniformly depending on grain), so you wouldn't maintain the tolerances needed for most CNC machines. 

That said, if you live somewhere with a constant (or complete lack of) humidity, such as in the desert somewhere, wood that has been fully cured (and/or fully weather-sealed) may work just fine.  For anywhere else, I suppose if there were enough play between the wood parts and the rods, then you may be able to make it work with a sacrifice in quality of the finished product and the risk of binding up of the threaded rods and couplers. 

If you aren't after high quality reproduction of your design (accuracy), then wood may be fine there, also.  Basically, this is a M-16 vs. AK-47 argument.  One has tighter tolerances and higher accuracy, and the other has looser tolerances and lower accuracy.  In the end, if it is good enough to do the job, that is all that matters.  Binding would be the only risk here.

[tanmanknex]

 in Utah it means yes!!!

[sssssbooom]

I disagree, In the past 2 weeks we have had snow, rain, wind, and 60 degree weather. And my doors lock is harder to lock in the winter. So I don't think the humidity is constant at all.

[CharMio]

disagreeing with a scientifically proven fact, i like your style! (wood takes more than two weeks to expand)

[3DMHuff]

So, if I hang a piece of oak and an equal size piece of balsa from the ceiling of my (partially insulated) shop and measure it daily, it will take two weeks to notice any change and each piece will be the same? I would think the balsa would start showing a change within a few days and the oak would take several weeks. Someone with more time on their hands should try that, then make an instuctable so I can figure out how to measure the moisture content in wood.

[NewB007]

Well, to be precise, the expansion of wood due to changes in moisture content due to humidity is a dynamic process. The variables include: wood variety, surface area of exposed grain, grain orientation, and the difference between the moisture content of the wood and the humidity of the air (and therefore the diffusion rate), among other things. Putting any sort of "time until" label on this would also require stating a coresponding % increase or reduction in length/width/thickness (whichever dimension is desired--they may not expand the same amount).

In short, this all depends on how accurately you want to (and can!) measure the changes.

[3DMHuff]

This subject is bothering me. I know a lot of people that that are master craftsman in woodworking and they all have different opinions when I ask about this. Some say if I lay the wood with the grain in the same direction as much as possible, it will be fine. Others say if I build it with grains criss-crossing it will work fine. So I asked the best wood craftsman I personally know, my Grandfather. He said, "What the hell do you need a CNC machine for?" I fear he is right.

[sssssbooom]

The two weeks is only explaining how often the weather changes. "if you live somewhere with a constant (or complete lack of) humidity, such as in the desert somewhere," Utah is not one of those. I never stated that wood expand faster then 2 weeks.

[tanmanknex]

I don't know what I was thinking when I wrote that so... Yeah. Anyway, the humidity where I live usually is pretty constant, though today during Marching Band it felt like Louisiana. Or Georgia. Or some other southeastern state where it's really humid. Humidity is the one thing I can't stand, weatherwise.

[sssssbooom]

You wrote it 6 months ago, I barely remember replying. Well until CharMio misunderstood my reply lol. :)

[socalcovey]

In Washington it means NO!

[amdivoff]

? what tool would you guys recommend to use to get clean cuts on the sheets

[Bowtie41]

I reverse the blade on either a circular or table saw with good results.Don't forget to put it back right when you are done!!!

[dylanwinn]

What exactly is the workable area for this? It looks like it couldn't be much more than 6 x 6 inches.

[countable]

Surely if you need an area larger than that, you could scale it up. These are just dimensions the author used.