CNC Router Plans and Construction
The following is a construction log of the CNC router I designed and built in 2025. Included in this log are the plans and construction details one would need to build their own. You will need a CNC to make some of these parts to the necessary accuracy, and in these cases CAD files or detailed drawings are provided. So if you know someone with a CNC, then you can make a CNC!
This is ongoing project, so if it seems to be incomplete then check back later. We will get there together!
Units of Measure
This CNC was designed and built in the USA. Normally this would mean US Customary units (feet and inches). However, almost all of the components and materials used are sourced from the rest of the world, meaning that they are built using Metric units. Even the plywood is a mix of US Customary (width x length) and Metric (thickness). So, to make things simple...
The default unit of measure for these CNC Plans is the Metric System.
A couple of items that were fabricated to US Customary are noted that way in these details (some bolts, V-groove bearings, steel angle, etc.). Otherwise, I will describe things in Metric.
To my friends in the USA:
I have had a career as an engineer and have used both systems extensively. It is not a political thing, it is just a tool. Metric is easier. The math is easier. Almost every thing we use was designed in Metric to even Metric units. It just makes sense.
And one little suggestion: Centimeters is for measuring the length of your arm, the depth of the snow, or the size of the fish that got away. It is not for design and manufacturing. It implies an accuracy of about the thickness of your finger. It is an informal unit, and pervasively used by we in the USA because it is close to the inch. For formal design: use millimeters. Actually, stick to the units that look like this:
1,000,000,000
1,000,000
1,000
1
0.001
0.000001
0.000000001
Giga, Mega, Kilo, one, milli, micro, nano. The units at the commas (every three zeros). Centi is not one of them.
(OK, rant over)
Design
When I was an apprentice, the senior engineers that taught me how to design were the ones that spent a career using a drafting board and drawing by hand. There was an art to it all. Proper drawing arrangement, the even use of white-space, and neatness were highly important in clearly conveying design information. We were essentially creating deliverables that only physically existed as pieces of paper. Those papers reflected your craft.
Because of this initial training, my favorite way of conveying design information is the good old two-dimensional three-view. But I also work in a world where 3D parametric solid modeling is now the standard for component design. No big deal, I can do that too.
From experience, if you are making one-off items out of flat panel materials (a special cabinet, a jig, a worktable, etc.) then it is much faster to draft that in 2D, copy-paste the part outlines to a nested cutting layout, and generate GCodes from that sketch. There is no sense to draw this stuff in 3D because you have to break it back down to 2D arrangements anyway.
3D solid modeling is necessary if the assembly is complex (and you can not otherwise visualize part relationships), or you will make the same thing but in different sizes (this is where parametric shines), or the output file needs to be in 3D (such as with CNC profiling or 3D printing).
(OK, second rant over)
With all of the above said, I normally design my CNC routers in 2D. The structure is not that complex. But just for you... In an effort to better convey the design, I have designed in both 3D and 2D. You are welcome.
Here is some images of the 3D model:
At this point, I could have continued in the 3D CAD/CAM package to create the final GCode files. However, I proceeded in a somewhat unusual fashion and used the 3D model to create 2D drawings. Crazy, right?!
Table Design
For starters, here are the free table plans:
On to the design...
The width of the table is determined by the width of the CNC gantry. The CNC gantry is 1,500 mm in total width (with 1,270 mm of travel) and this is based on common linear slide lengths. The gantry construction and final roller locations then constrain the table width. You can get an idea of this from the images above. The final width of the table is 1,390 mm.
The cool thing about this design is that the table length can be as long as you need it. With the width being wider than four feet, when using a 4 x 8 foot sheet of plywood you have to cut the width from the eight foot axis of the sheet. This leaves a bunch of 4 x whatever pieces of plywood (those will get used). For international compatibility (and the fact that I like round numbers), I designed the table length on integrals of 1,200 mm sections (yep, just less than the four foot width of the 4 x 8 plywood).
Here are some table length options:
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2,400 mm : Two sections. A nice little table but not long enough to cut fully from 4 x 8 sheet stock.
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3,000 mm : The minimal length to cut 4 x 8 foot sheet stock.
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3,600 mm : Three sections.
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4,800 mm : Four sections. My favorite. Long enough to cut 4 x 12 foot sheet stock, cut 12 foot tubing, build an aircraft wing, and cut 4 x 8 foot stock with room at the end to build.
These four choices are in the image below:
One very impractical length is:
- 1,200 mm : One section. You only have about 800 mm of cutting length, but it is a nice little table if you are really limited on space and only plan on cutting, etching, or engraving small stuff.
What the hell, let's build this one!
The this table will be 1,390 mm (gantry axis) x 1,200 mm (table axis). You can see in the image above I have drawn the side of the tables. The next 2D step is to project that into the three views:
With these three-views, I can quickly cut-paste out the geometry to create part outlines. These then get nested onto how they will be cut from the 4 x 8 foot plywood:
Building the Table
Steel Angle Rails
The gantry travels along linear rails which are simply steel angle. These are 1 x 1 x 3/16 inch and as long as the table. These are typically available in 20 foot lengths. I always just get several full length pieces to avoid the supplier from bending them during handling...
It is very important to make sure this steel angle has not been bent! Not even a little bit.
When you purchase these, do not let anybody just grab one piece in the middle and pick it up. Usually these are delivered to the steel supplier in a massive bundle and are put on a shelf all tied together. Start there. Pick out four pieces on that shelf and before anyone picks them up, immediately wire tie them into a tightly nested group. Then, get several people spaced out to carry them. Do not let them get bent.
Here are four pieces ready to go. These started off as twenty foot long pieces all tied together every three or four feet. These look rusty and rough. This is typical.
Grinding the Rails
V-groove bearings will ride along the top flange of the angle, and to make things smoother and a bit more accurate, the top is ground. On the last CNC table I built, I simply cleaned it up by hand with a file. This time I built a jig which holds an angle grinder.
This jig holds the grinder at a 45 degree angle:
Not a whole lot needs to be ground off:
Try to make the ground flat about 1.5 mm wide. Actually, start with a 1.0 mm flat. Then if you find a low spot grind everything down to that low spot. Worst case, grind to a flat 2.0 mm wide. Regardless, just make them all exactly the same.
You can eyeball this. It is easy to tell which areas need a little more... make the grinds even the whole length. No gouging. No high spots.
Not all pieces are extruded exactly the same. In this set, two were a little shorter (less than 1 x 1 inch) than the other two (you can not tell from the image, you have to measure). So I paired them so that the ones that will go on the top of the table are the same height, and the ones on the bottom are the same height.
Again, these look rusty and rough. This is typical:
Drilling the Rails
The rails are connected to the table using M5x40 flat-head screws. The spacing needs to match that in the DXF file for the table. For this build the spacing was every 100 mm with the first 50 mm from the end. The position of the hole is 15 mm from the outside edge of the vertical side (roughly 10.4 mm from the tip of the horizontal side, depending on the accuracy of the steel extrusion).
You can measure and drill by hand, but with a CNC here are the steps:
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Screw down a piece of scrap plywood/particle board as long as the rail.
-
Cut a precision slot the same width as the steel angle. At the same time, cut a precision edge defining the end of the rail.
-
Then the rails can be placed in the slot and the CNC drills the accurate holes. Easy.
Here is a time-lapse video of the slot being cut:
CNC Trick: On my first try my slot was too narrow. So I decreased the diameter of the tool in the CNC's tool table from 6.35 mm to 6.00 mm. I ran the program again and with that new setting the tool compensation offset was less and it cut closer to the defined edge.
For drilling I start with a small bit and work up to the desired hole diameter. My 3/32 inch bit gets a lot of use this way. My second pass on the CNC was with a 1/8 inch bit (yep, I only have a couple of collets for my spindle and the two small ones are 3/32 and 1/8).
Here are a couple of the holes being drilled:
The holes are now spaced and positioned as noted above. The position of the hole is 15 mm from the outside edge of the vertical side:
I do not have a spindle collet for a 5 mm bit, so the final drilling and countersink were done on a drill press. I do not have an official Metric bit for a 5 mm clearance hole, so I used a #7 (5.11 mm, 0.201 inch). Countersink only the set of rails to be located on the top of the table. Here are the results:
Here is the DXF file I used to cut the slot and drill the holes:
WorktableCNC-RailDrillingJig.dxf