This instructable will show you how to construct a CNC Router that will allow you to cut 3-D shapes out of wood, plastic and aluminum using a standard hand held router. Recently I have noticed that more and more projects on instructables have involved the use of some sort of CNC machine, be it a laser cutter, 3d printer, milling machine, etc. I wanted to join this revolution of digital fabrication and start making my projects even better using these tools. So about a year ago I set out to find a way to make this possible and came to conclusion that a simple 3 axis CNC router would be the best option to get things going. I started doing some research and decided to design and build my own machine. This instructable steps though all the parts needed to build the machine I have designed and the reasoning behind why I built the machine the way I did. It also includes an explanation of CNC technology and would be a great reference for anyone looking to learn some metal fabrication skills. My hope is that someone might use these plans to build this router for themselves or at least draw some inspiration from my design. I have created 2d drawings of all the parts with complete dimensions and specs, details on how to build each part, a complete parts and tools lists with prices and links, a basic wiring diagram and an explanation of the design.
I have designed this router to be very versatile and hope to also use this same machine as a 3-D printer and a hot wire foam cutter in the future. This machine is constructed from rectangular steel tubing and aluminum plate and was fabricated using a small horizontal band saw, bench top drill press and flux core MIG welder. There is no need for high precision and expensive tools to build this machine. Using the techniques I have listed in this instructable for marking, centering, drilling and tapping anyone with the desire to build something well, will be able to complete this project. There are no angles to cut or parts that seem impossible to get right, just straight cuts and holes to drill. The machine bolts together and can be adjusted for square and levelness on each axis.
For those of you who already know about CNC routers here are the specs for my machine.
Travel: X-Axis 23in
Linear Guide: Fully Support Round Linear Rail and Mounted Bearings (20mm, 16mm, 12mm)
Linear Drive: 1/2”-10 5 Start Precision ACME Screws and DumpsterCNC Anti-Backlash Nuts
Drive Motor and Controller: Gecko G540 Controller with Gecko 280oz-in NEMA 23 Stepper Motors
Construction: Welded 1”x2” Steel Tubing and 3/8” Thick Aluminum Plate
Spindle: Bosch Colt Trim Router
Rapid Speed: 200ipm (inches per minute)
Cutting Speed: 1/4" end mill, full width cut, 0.100" depth of cut, 50ipm, material - hardwood (This is a fairly easy cut and is probably less than half the true cutting capacity)
Step 1: What Is CNC
So that was really basic, let’s get to some of the specifics on my type of CNC machine. There are many different types of CNC machines but they are most distinguishable by the type and size of material they are designed to cut. In general if someone refers to a CNC “milling” machine they are referring to a metal cutting machine and if they say it’s a CNC "router" it means a machine made to cut wood, plastic or other soft materials. This instructable will show you how to build a CNC router.
If you are learning about CNC and have considered building your own machine I would highly recommend taking a look at this website cncroutersource.com There is a wealth of knowledge about designing your own CNC router and well as explanations of the different types of router designs and list of terms commonly used in CNC lingo. When I first considered building CNC machine I was lucky enough to stumble across this site and it helped me make a lot of the basic design decisions early on.
Once you have read though all you can on the cncroutersource.com you can step up to the big leagues and join the cnczone.com forum. Here you will find a vast amount of information and huge community of active users all doing the things you want to do for your CNC. There is a specific section of the forum for CNC routers and many build threads have been posted that will make you drool with jealousy. Have a question about CNC? A simple search of this forum will most likely answer any and all of the CNC questions you have. Keep in mind though that a lot of acronyms and jargon are used on cnczone but if you have read cncroutersource you should be able to figure it out.
Step 2: CNC Router Design
- Decide what length of travel you need for each axis (if you have a specific project in mind for your cnc then start with it's sizes requirements)
- Decide what type of linear motion system you will use for the machine
- Decide what kind of linear drive you will use for each axis
- Decide what type of drive motor and controller you will use
- Decide the material you will use to construct the machine
- Based on the previous decisions, design a machine on paper or a CAD software of you choice (this does not have to be a complete design, just enough so you know the total quantity of the materials you'll need)
- Determine if you will need any special tools for your design
- Determine the overall cost of your design, which includes the cost of tools you may not have
- Decide that you can't spend that much money on the machine and return to step 1
Here is my thinking for each one of the design steps I outlined:
- Travel: My first thought for a CNC machine was to build molds for the vacuum forming machine I have already built. So I decided to build the machine with roughly 12”x24”x6" of travel because that how big the forming platen is on my vacuum forming machine.
- Linear Motion: There are many options to choose from for linear motion. Commonly used methods for CNC routers include, drawer slides, skate bearings, v-groove bearings, round linear rail and profile linear rail. These are ordered in terms of cost, I would recommend going the best system you can afford. You can save some money in other areas of the machine but getting a good motion system will pay off in cutting quality. I chose to use round linear rail. This system uses precision ground and hardened steel shafts and linear bearings that use small steel balls that roll on the shaft and re-circulate through channels within the bearing. This offers smooth low friction movement and has good resistance to forces placed on the bearing in any direction. There are many different manufactures of these types of rails and bearings and costs can vary quite a bit. I got my rails and bearings from a reseller in China on ebay. The ebay store is linearmotionbearings and the prices were the best I found online. They often sells kits with three sets of rails and two bearings for each rail, which is what is needed for a 3-axis CNC. The kit I got uses 20mm x 800mm long rails for the x-axis, 16mm x 500mm long rails for the y-axis and 12mm x 300mm long rails for the z-axis. This kit cost me $223 dollars shipped.
- Linear Drive: The three basic options to drive each axis of a CNC router are ribbed belts, screws, and a rack and pinion. The most common on DIY CNC routers are ACME screws, ball screws and rack and pinion setups. Screw drive systems work by attaching a nut to the movable part of each axis, a threaded rod is then fed through the nut and locked into position at both ends. The screw is turned by the drive motors and the nut moves along the screw. ACME screws have trapezoidal threads that are either cut or rolled into a steel rod. ACME screw threads are used on common C-clamps. Their thread shape makes the screw stronger than the threads on standard bolts. When these threads are precision cut they are perfectly suited to drive a CNC router. Probably the most common and cheapest ACME thread size is 1/2"-10. That means1/2” in diameter and 10 threads per inch. Ten threads per inch means that if the screw in spun around 10 times the attached nut will move 1 inch along the screw. For any screw size multiple individual threads can be cut on the screw, this is referred to as the number of starts the screw has. A single start screw has one thread a 2-start has two threads and a 5-start has five threads. What is the significance of multiple threads on a screw? Well there are two things that make multiple start screws better for CNC machines. First multiple start screws are more efficient at turning the rotational force on the screw into linear force on the nut. This means it takes less torque for the drive motors to move each axis. Second, multiple start screws increase the lead of the screw, which is how far a nut would move if the screw was rotated once. To determine the lead for a screw divide the number of starts by the number of threads per inch. For example, a 1/2”-10, 5 start, ACME screw would have a 5/10 or 1/2” lead. This means for every rotation of the screw the nut moves 1/2”. This is important because the electric drive motor can produce the most torque at low speeds, and with a higher lead the nut will move farther per revolution of the screw and that means the motor can spin at a lower speed to move the axis of the machine. For my machine I chose to use a 1/2”-10, 5 start, precision ACME screw from Mcmaster Carr for all 3 axis.
- Drive Motor: For CNC routers two basic options exist, stepper motors or servo motors. Stepper motors are used in the vast majority of DIY CNC routers. CNCroutersource has some excellent information comparing these two types of motors. The key difference in these motors is servo motors provide position feedback to ensure proper positioning while stepper motors do not. I chose to use stepper motors for my machine mainly due to cost. Servo motors are more expensive and require more expensive controllers then comparable stepper motors for the sizes that are commonly used on CNC routers. Also stepper motors are highly supported in the DIY router community and are available from many different retailers. When looking in to stepper motors and controllers I found many options and price ranges from less than $100 to more than $500. When deciding what to get for my machine I came to the conclusion that these systems are so universal that I could use my controller and even steppers for other CNC projects in the future. Knowing that I wanted to get good performance and long term reliability I decided to go with American made components from Gecko. I purchased a Gecko G540 stepper controller which can control up to 4 stepper motors at once and connects to a computer through a parallel port. I also purchased 4 280oz-in, NEMA 23 stepper motors from Gecko which are also made in America. The control software I decided to use is called Mach3 and it uses a computer's parallel port to send signals to the G540 which controls the stepper motors. Mach3 CNC control software can be downloaded and used for free, but is limited until you buy the software for $150. Mach3 is probably the most widely used software for DIY CNC machines and is well supported.
- Construction Material: Most DIY CNC routers are built using either MDF, aluminum extrusion, or steel. MDF can be easy to work with and cheap to buy and many first time builders use this material. Slotted aluminum extrusion, commonly from a company called 80/20, is used on many DIY CNC router design plans available on the internet. It offers many design options due to the large amount on mounting brackets and configurations the slotted design allows. Aluminum extrusion would also be the most expensive of the three methods I listed. Steel is also used to construct many DIY routers. Square tubing, angle, and flat stock are common and can usually be locally sourced. In most cases steel machines are welded together so a welder and the ability to weld are necessary. Steel is generally going to be less expensive per foot than aluminum extrusion. I chose to use 1”x2”x0.065” steel tubing to construct my CNC router. I was able to purchase a single 24ft piece from a local steel supplier, Industrial Tube and Steel. They even cut it in half so I could load it in my car. If you don’t have a local steel supplier I would suggest looking at speedymetals, I have purchased from them before and they have good prices and deliver fast. I have experience welding and a flux core welder, which is similar to MIG welder but doesn’t require shielding gas. If you want to get more information about welding take a look at this great instructable from Phil B, Learning to Weld. Using steel also requires the use of metal working tools. I used a small horizontal band saw to cut the tubing and a small bench top drill press to drill holes. I have included a few tips about working with metal and some tools that make life a lot easier in this instrucable.
- Design: You can use what ever software you are comfortable with when designing the machine. You could even just draw your machine on paper. 123D from Autodesk and SketchUp from Google are both free 3D modeling software programs you could use. Many of the parts I used on this machine came from McMaster-Carr. Their website provides drawings for many of the items they sell including 3D models which can be downlaoded for free.
- Tools: I used a number of tools to build my CNC machine and they are listed on the Tools step. Some of the tools are specific to working with metal and are essential to getting the best results. I also made a few of my own tools to make building this machine much easier.
- Cost: I estimated my cost for the complete machine and electronics around $1500.
You now know my decisions and hopefully understand my reasoning. I think I have a pretty good combination of parts that has exceeded my expectations. If you decide to build a machine based on my plans I have everything laid out in the following steps.
Step 3: CNC Router Parts and Materials
|Hardware||91290A228||M5x12mm SHCS, (sold in packs of 100, 2 packs needed)||McMaster||2||6.89/pack||13.78|
|93070A123||M5x12mm SHCS Low Head (sold in packs of 50)||McMaster||1||9.63/pack||9.63|
|91290A334||M6x35mm SHCS (sold in packs of 100)||McMaster||1||10.16/pack||10.16|
|162075||8-32 Machine Screws with nuts||lowes||1||$1.00||$1.00|
|215901||3/8” Threaded Rod with nuts and washers||lowes||1||$10.00||$10.00|
|57870||1/4"-20 x 1.5" Bolts with nuts and washers||lowes||6||$5.00||$5.00|
|CNC Specific Parts||AC12105-LN||1/2"-10, 5 start Acme clamping shaft collar||dumpsterCNC||3||$25.00||$75.00|
|AC12105-TC||1/2"-10, 5 start Acme anti-backlash nut||dumpsterCNC||3||$10.25||$30.75|
|9889T201||Oldham coupler, 1/4" bore, clamping||McMaster||3||$15.75||$47.25|
|9889T204||Oldham coupler, 1/2" bore, clamping||McMaster||3||$15.75||$47.25|
|59985K63||Oldham Coupler Disc||McMaster||3||$5.02||$15.06|
|99030A704||1/2"-10, 5 start Precision Acme Screw, 6ft long||McMaster||1||$57.50||$57.50|
|6157K14||1/2" bore clamping shaft collar||McMaster||3||$2.47||$7.41|
|2938T11||1/2" bore bronze bushing w/ flange||McMaster||6||$0.63||$3.78|
|N/A||Bosch Colt Router Mount||k2CNC||1||$55.00||$55.00|
|N/A||Bosch Colt Hand Held Router||Amazon||1||$100.00||$100.00|
|N/A||Linear Rails and Bearings||linearmotionbearings, Ebay||1||$223.00||$223.00|
|Electronics||G540||G540 Stepper Motor Controller||Danmauch, Ebay||1||$240.00||$240.00|
|G723-280-4||Gecko 280oz-in Stepper motor, dual shaft||Gecko||3||$60.00||$180.00|
|295929||48V 12.5A Power Supply||Jameco||1||$114.95||$114.95|
|15748||DB9 Male Connector, Solder||Jameco||3||$0.55||$1.65|
|15771||DB9 Female Connector, Solder||Jameco||3||$0.55||$1.65|
|15722||DB9 connector Hood||Jameco||6||$0.49||$2.94|
|645722||Cat 5e Cable, 100ft (only about 30ft is needed)||Jameco||1||$14.95||$14.95|
|69792||Combination Power Switch with light||Lowes||1||$7.99||$7.99|
|56592||8ft 12-3 power cord||Lowes||1||$10.00||$10.00|
|7739||grounded(3 prong) power conector||Lowes||1||$2.77||$2.77|
|Material||N/A||1x2x.065" Steel Tubing 24ft||Industrial Tube and Steel or Speedymetals.com||1||$48.00||$48.00|
|N/A||1x1x0.125" Steel Tube 6ft||Industrial Tube and Steel or Speedymetals.com||1||$15.00||$15.00|
|8975K683||Aluminum 6061, 1/4" Thick X 2-1/2" Wide X 3' Length||McMaster||1||$17.88||$17.88|
|8975K441||Aluminum 6061, 3/8" Thick, 6" Width, 1' Length||McMaster||2||$17.72||$35.44|
|1658T43||Aluminum Tube, 3/8" OD x 0.145" ID x 8ft long||McMaster||1||$6.61||$6.61|
|8 97 5K 713||Aluminum 6061, 1/4" Thick X 2" Wide X 3' Length||McMaster||1||$17.23||$17.23|
|37461||4'x8'x3/4" MDF Sheet||Lowes||1||$32.00||$32.00|
I know this list is missing a few minor things that most people already have, so I didn't include them. Most people will need to buy these parts in order to build the machine.
Step 4: Tools
|Tool Description||Part Number||Supplier||Price|
|5/8" Dia. Reduced Shank Drill Bit||2933A28||McMaster||$20.37|
|Drill Tip Counter Bore for M5 SHCS||29445A23||McMaster||$15.78|
|Hand Tap, 5mmx0.8mm Pitch||8305A36||McMaster||$5.90|
|Dykem Layout Fluid||2131A15||McMaster||$7.79|
|Tap Magic Cutting Fuid||10015K16||McMaster||$9.69|
|Right Angle Welding Clamp||190939||Northern Tool||$50.00|
I also used these tools that I already had:
4.5" Angle Grinder
Flux Core Welder
Transfer Punch Set
Step 5: CNC Router Plans
Step 6: Drilling a Good Hole
- Apply Dykem near the locations where holes are needed on the part
- Use your scribe to mark the locations of the holes with two intersecting lines, use a combination square to measure for the location of each hole
- Use a small transfer punch to mark the location of all holes (transfer punches normally have a sharper tip which should make marking the center easier)
- Use a center punch placed in the dent made by the transfer punch to make a larger dent for the drill bit
- Place the part on your drill press and center the mark and the drill bit by bringing the drill bit down onto the part with the tip of the drill in the dent made by the punch, hold the drill bit in this position
- Clamp the part to the drill press table; I usually did this with a welding vice grip.
- Bring the drill bit up off the part and turn on the drill press, slowly move the drill bit down onto the part making sure the bit centers on the dent.
- Bring the bit back up, turn off the drill press and squirt some tap magic directly on the drill bit. Let it flow down through the flutes of the drill bit until a few drops fall on the part.
- Turn the drill press back on and proceed to drill the hole. For the best results you should follow a technique called peck drilling. To do this drill into the material between 1/16" and 3/16" deep then as chips begin to build up move the drill bit up and out of the hole. This allows for the chips to fly off the drill bit which ensures that the bit will not get jammed up in the hole. Then repeat this process until you drill all the way though the part or to the depth you want. Peck drilling is a common CNC technique and is especially important when drilling small holes, less than 1/8" diameter. Its also good re-lubricate with tap Magic during this process.
- Un-clamp the part from the drill press and de-bur the bottom side of the hole and clear any chips off of the drill press table. This ensures that the part will still sit flat on the drill press table for the next hole you drill. Proceed to the next hole in the same manner.
Tapping a hole is the process of cutting threads into a part so that you can fasten a screw to the part. I made a special tool to help in tapping the many M5 holes for this machine. The tool is really simple, it’s a hole drilled in a piece of 5/8” x 3/4” aluminum bar. The hole is drilled with a #9 bit, which is the same size as an M5 tap. You place the tap in the hole and hold it in place over the hole in the part you are tapping. The tool holds the tap square and true to the part you are tapping which is very important. Here is my process for tapping a hole.
- Make sure the tap is clear of any chips or debris. I used a air compressor and blow gun to clean the holes and tap.
- Put some tap magic on the tap and put it into the hole of the tapping tool. Place the tip of the tap into the hole on the part you are tapping and sit the tool flush with the part’s surface.
- Hold the tool in place and turn the tap clockwise (for a standard right hand thread).
- Turn the tap 3/4 to 1 full turn and then back the tap out, turn counter-clockwise, by about half a turn. You should feel the tap break free a little when this is done which is good. What this does is breaks the shavings in the hole free and they fall into the flutes of the tap. This allows you to continue tapping the hole without having the shavings build up which leads to breaking the tap off in the hole if you are not careful.
- Continue like this until the hole is tapped. Then clean the tap and tool and proceed to the next hole.
Step 7: Stepper Motor Mounting Plate
As a side note, at this point you should also make the jig for the gantry mount, step 16. This will help with many of the parts as you build.
Step 8: Standoff
Step 9: Drive Motor Assembly
This is a video from Ruland and has a great description of the the Oldham couplers. The couplers I have listed from Mcmaster are made by Ruland.
Step 10: X-Axis Frame
Step 11: X-Axis Drive Nut Mount
Step 12: Gantry Upright
Step 13: X-Axis Assembly
Step 14: Y-Axis Rail Mount
Step 15: Y-Axis Upright
Step 16: Gantry Mounting Plate
Step 17: Y-Axis Drive Nut Mount
Step 18: Y-Axis Assembly
Step 19: Z-Axis Mounting Plate
Step 20: Z-Axis Drive Nut Mount
Step 21: Z-Axis Drive Screw End Mount
Step 22: Z-Axis Assembly
Step 23: Router Mounting Plate
Step 24: MDF Base
Step 25: Table Support
Step 26: Work Table
Step 27: Router Assembly
- Philips Head Screw Driver
- Cresent Wrench
- 9/16" Socket and Ratchet
- 9/16" Wrench
- Allen Keys Sizes
Step 28: Wire the Electronics
Step 29: CNC Software
Step 30: First Test
So now its your turn. Go build this CNC machine and join the digital fabrication revolution!