Introduction: The DIY BeAsT CNC

About: I am a lifelong "Maker of Things" and have a very fortunate array of mistakes and misdeeds that have lead me to some incredible insights and designs I am now implementing to the world.

I have a friend who has some of the most amazing and truly monstrous CNC mills and lathes you could imagine and I saw this one in action with an enormous block of 6AL4V Titanium on the deck and thought how fun it would be to make such a thing.

I work out of this facility as well and could have easily done everything in here but I really wanted to do this on my own and with a simpler tool set so I packed some stuff and started the project in a dusty corner of our our horse barn and this is where it sits running today. You don't need anything fancy just solid because it's going to get heavy!

I make some pretty neat stuff I can't really share including Supercritical Fluid Reactors and such so this also appealed to me as a way to make something I could actually show other folks. I have been fortunate enough to have a lifelong interest in making things and have some fairly refined skills in working with a wide range of materials and such so a project like this is not easily done but it can certainly be done and I am going to point out some interesting stuff and sources I hope along the way.

It's a bit difficult to get into finite details on a very complex build without boring you all to tears and I think it's most important not to copy something but rather be inspired and create something uniquely your own.

I am a HUGE fan and advocate of eBay and pretty much all the core hardware and materials are out there if you know what to look for and where to find it. I get Siemens power supplies or Allen Bradley VFD's and pay pennies on the dollar rather than cheap imported stuff as well as servos/steppers and all the associated motion hardware. I am going to show you an amazing resource for the tool plate I constructed the BeAsT from and I am so fortunate to have him right down the road from me but he ships everywhere.

OK so this is what I want in a scaled down by ohhhh about 75 tons version so let's get started!

It will CNC Mill, 3D Print and Laser etch when all completed but mainly high precision mill some very specific plates I need so it has a bed of 15.5 in Y and 25.5 in X and about 13 in in Z but it can extend higher. I also have a servo driven 4th axis in C which will be a lathe head with the live spindle above as well as an insert style quick change.


I used exclusively Gleich toolplate which is a surface ground to very high tolerance on 2 sides cast Aluminum so a 1/2 inch slab is literally .500 unlike the variations you will fin in regular 6061 0r 7075 and etc.

USA Metal Online are my absolute go-to folks and Chet Mills and his guys will take great care of Instructables folks like he has for us on numerous projects. They eBay market all sorts of materials that are "Drops" or cutoffs from the much larger pieces they sell to large scale consumers all across the country and we get to capitalize on their scraps let me tell you!

I will cover more of the materials as we step through the process.

Step 1: Getting Started

Ok so we are going to build a machine but we are going to have to drill and tap a TON of precision holes and machine some alignment slots and the like so we HAVE to have a machine to do it with some degree of accuracy.

I shelled out $1500 bucks, I will recoup later of course when I sell it, on this nice vintage round column mill.

I spent the first week or so getting the mill up and running with an i-Gaging DRO setup I got off Amazon and hooked it up to an older Android tablet I had with a neat kit from Yuriy's Toys and I was ready to accurately drill and tap to my hearts content.

I also had to get a bit of tooling and make a number of fixtures and such along the way. Fixtures are a lot of fun to make nd provide amazing work holding and perhaps we'll do some Instructables on that in the future.

Step 2: Design and Fusion 360 Component Build

Ok so I actually spent the entire spring in Ft Bragg with the onset of Covid 19 and it was in my downtime there while in the Campground that I began the overall design process and here's another amazing tip for those of you with an iPad capable of using the's a truly amazing app for an iPad and while I designed everything later in Fusion 360 in detail I was able to do a ton of initial work in Shapr3D. Shapr3D is a really feature rich app you can do some amazing work in so I highly recommend it to anyone who has not heard of it. It works on a subscription basis and the month to month is reasonable to say the least given how quickly you can pick it up and the depth with which you can go with concepts.

After hashing through concepts on my iPad I popped into Fusion 360 and began really diving into dimensions, hole spacing and the every formidable TAPPING but we'll get to that in due time.

Fusion 360 is simply amazing to say the least and while I am a near complete newbie I can accomplish some amazing results with trial and error and lots of YouTube...shouts out to NYCNC, Newfangled, VinceBuild and a whole host others.

I also used a number of F360 designs available out there to get a number of components into my workspace in a hurry including bearing rails, ball screws and spindle without having to go through and model everything myself making the design process extremely accurate and quite timely given the complexity of what I was dealing with.

Step 3: From Fusion 360 to Gleich Plate

I won't bore you all with all the drilling and tapping but needless to say it was a LOT of drilling and tapping to get something to the point of photographs.

I use the mill for the entire process. I use Fusion 360 to get all my dimensions modeled and since I am using a manual mill, yes I have to very carefully align the parts and edge find and zero my DRO and then spot, drill and tap. I carefully order the operations so that I can trace and retrace my steps with each operation and you should carefully think about how that all works. Your steps are critical to repeatability especially when you get to tapping operations.

Tapping is something I do completely in the mill by chucking the tap in a collet and lowering my VFD to a bare 5-10 cycles(Hz) and in aluminum I add a copious amount of good old WD40 or AlumaTap if I have it but WD40 is my goto. I have snapped many a 1/4-20, 10-32 and 5MM tap by hand but not, KNOCK ON WOOD, in the mill for many a year. The key is your VFD compensating for load at those lower frequencies which it does a great job of but will stall if anything goes seriously amiss. The chances of serious amiss with misalignment are greatly reduced having pre-planned the spot drill, drill and then the tapping to within a thou or less with planned DRO travel

Anyway here we have the basic axis worked out and we can make things more intricate from here.

Step 4: Adding Complications Like in a Watch

I approach things in a very organic matter though I am using Fusion 360 to develop specifics as I go along and I encourage you all to do the same. I look at my current state and then my available materials and then my design expectations and work in the details from there and it is a strategy that has served me very well for many years and a number of patents.

Rough things out and make sure they work in the real space and then with the help of Fusion go in and refine it down to the thousandths of inches we need for such a project.

Lets talk about component selection here because you start to see some of the motion components I have sourced from eBay. I could have gotten imports but I dug a bit deeper and sourced Ground NSK ball screws with a high speed pitch....meaning they move a pretty considerable distance of 20mm per single revolution which is something I wanted and as I am using Servos its pretty amazing in practice. Speaking of servos I got them guessed it eBay...I even payed $37.00 for brand new Teknics servo driver...I actually had to buy all 10 they had since they had no clue how to price them...the deals are out there and always out there you just have to put in the time.

So this build has 25MM ball screws and linear rails on X as well as 20MM rails and they are set perpendicular for best load carrying in one plane and guide continuity in the other...the 25 carries the bulk of the load and the 20's aid in guiding at a 90 degree angle to the load. The 20's I had from something else and were HiWins but the bulk of my rails are all NSK and were cheaper or equivalent to the imports. Several were brand new and several were used but in excellent condition and my entire build at this point has ZERO or 0.0000 backlash anywhere and goes at over 200IPM with ease.

Fusion 360 is absolutely CRITICAL in accurately setting up perpendicular rails as I have done because if you try to wing this and you are off even slightly your rails are going to bind in a horrid manner over the entire travel path. Your setup and config for these operations would be nearly impossible without Fusion 360 because you can use extremely accurate models of your rails and screws downloaded directly from the manufacturer to set all your spacing. When I trial assembled the X rails with the Y bridge in place it absolutely glided like it was on water and I did the exact same double screw and motor with perpendicular rails with my Y axis as well.

Again with the Y axis you can see the high speed lathe style screws and double motor configuration.

Step 5: Getting Movement

I have the roughly assembled base and gantry with the Y axis in place on my welding fixture table and it's really starting to come together here.

I have been drilling and tapping and machining for several long weeks of nights and weekends here and of course I am doing this in a corner of the horse barn of all places so I could keep after it after hours and out of sight.

I have a pair of NEMA 23 double stack servos driving the Y axis here and a large NEMA 34 triple on the Z and again a pair of triple stack NEMA 23's. Triple stack or double stack refers to the number of actual motor units in the servos...a single stack is a bit of a pancake style while doubles and triples subsequently double and triple the stack length adding increased holding torque and power. These all have built in encoders and controllers that I have set to quadrature and need only configure my software to send the necessary A+ B+ etc. signals directly from the controller to the servo greatly reducing wiring and component complexity. They do any lost stepping internally so there is no need to provide output back to the software which maintains an incredible level of accuracy at blinding speeds. I microstep them at a multiple of 32 meaning each rotation is subdivided into 6400 individual steps and while they can actually handle a staggering 51,200 that us resolution that simply adds complexity for this application rather than increasing accuracy.

It bears mentioning here that you will have a considerable amount of time dialing in the accuracy of your machine once it's actually built to assure real finite accuracy. I spent more than a day with a .0005 dial indicator moving across a very broad range of distances to get it really dialed in. As an example I had solid repeatability at .500 inches but throw it 20.00 and watch what happens...that require 2 dial indicators and of course I have double gantry rails on X that had to be very carefully aligned with both motor stepping and careful manipulation of my limit switches at the end to assure gantry alignment.

I was also very keenly aware of maintaining absolute rigidity so these components are 1 inch tool plate and assembled in such a way as to lock everything in place...not just face mounted but notched and precisely aligned.

Step 6: A Bit About Fasteners

I want to talk briefly about the paramount importance of good fasteners. This machine will weigh nearly a thousand pounds when complete and I am expecting some pretty high resolution of accuracy and NONE of that is possible without high grade fasteners.

I have used Holo-Kromes over the years and they have been my choice for a number of reasons and a big one is availability in bulk for short money(relatively) on eBay. Notice the Alllen from "Allen Wrench" and you get the idea about who they are.

Skimp where you must but not on the glue that holds you projects together.

Step 7: Duel Rail Drive Complexity

The X axis is my longest and therefore a bit trickier to accomplish since it's driven by 2 screws on opposite sides of the machine. The Y axis is also double drive but they work in tandem on the same drive point and on the same plain of rails. The X axis rails and screws are also considerably larger because they carry and transfer the weight of both the Y and the Z axis and importantly while both of those axis are generating dynamic and opposing forces while in motion.

I built them over several iterations in Fusion 360 until I had them exactly how I wanted them and then I assembled them on my largest granite surface at home which is surprisingly flat and sits out on my deck thankfully so the Big Boss was not too miffed abut machinery residing on countertops.

I carefully aligned the screws and mounts on the side rails and attached them to the gantry sides which I had to disassemble and machine of course for about the 23rd time but I was assured that everything would work as I hoped.

Step 8: Brain Surgery

This is where the rubber really starts to look like it might hit the road someday. We're better than a month and half in here but thankfully I am seeing some light at the end of the tunnel.

The electronics is the really the heart and the brain of the whole mess and I really had to put my thinking cap on here and proceed in that "organic layout all the stuff you need to get in there and see where it all lands" mentality.

I started with a WARP9 Ethernet Smooth Stepper or ESS and got an amazing break out board or BOB for it from CNCROOM. The crazy thing that has to be mentioned is CNCROOM is in Thailand and I ordered it on a Wednesday and it actually showed up on that Saturday....IN NH!!!!! I was absolutely shocked with not only the quality of the product but it got halfway across the world for $23.00 in a little over 2 days. I also want to say when I need support Weerasak the creator was about the most helpful person in relation to not only his own product but also the ESS and the servos I was using.

Take your time here...bring your control voltage stuff in from one side and your supply voltages in from the other and try to keep them isolated as much as possible. Use shielded cable and secure the drain on the motor/signal side ONLY.

I attached a 3/4 inch plate 7 inches deep and about 14 inches across to mount the base of the cabinet to and tapped several mounting holes for it. The important thing her is to make another plate like .250 in thickness to mount inside the cabinet and spread the force of holding the cabinet beyond the bolt heads even with washers. I intend to make a frame surround the unit that will also help support the top of the control box but it will go on close to last and I want that box mounted very solidly while I debug and tune the machine.

Amazing overall experience and mad crazy cool blinking lights that are mesmerizing in an otherwise dull control cabinet...;)

I again opted away from a small import power supply brick and got an Antek servo class 70V monster. To put it into perspective the Antek weighs over 20lbs while an eBay import less than a pound. These are unregulated so the are a bit different but rock solid under high load demands and identical to what you find in high end machines running DC and the cost was about $150.00 so money well spent. I also added a Buck converter for some slightly less than 60V flow for the smaller servos that errored out sometimes with the 63 the Antek was making.

Also noteworthy are the ultra bright LED flood lights I mounted to the gantry plates and they are amazing...15 Watts off my 10 Amp 24V PS and they light up the work area incredibly. I am surprised I don't see every DIY build using them. I got them off Amazon for less than $20.00. Upcoming pictures show the amazing effect they have especially for my nearly 60 yr old tired eyes.

Again eBay for Wago terminal blocks with spring clamps and never ever terminate a wire in a block without a ferrule...get them right off Amazon and a good set of ferrule pliers.

Twist your wires up and use color coding that helps identify your wiring thoughts...24V one set, Signal another and line voltage yet another but all themed...helps immensely later sorting through issues or adding upgrades and modifications.

Limit and Homing switches are really critical and again no import cheapies were going to fit the bill here so I got 7 Turck Micro units and they are amazing and also all over eBay. The only thing about them is mine were new and the ends come trimmed but good god if you have to bare more of the jacket it's a molded skin and has to be very carefully done but the stuff is TUFF!

Step 9: Final Mile

It's been quite the road and a lot of fun and rewarding results along the way and most importantly I continue to learn a few things along the way.

As I said previously the lights are absolutely spectacular to work under and I highly encourage anyone with a CNC to incorporate them.

I am using an import Spindle but opted for the 4.7KW model as it has a far more robust bearing assembly and its just not that much more than the 2.2KW model. You will never really load a high frequency spindle motor so when these things are running at 300Hz+ they are not using a lot of amperage so I am using a VFD with an 11 Amp rating @2XX V as it will be more than adequate.

I started off with a version of Mach4 but I have to be honest and agree with some other folks it's really still a hot mess. I spent nearly 2 days thrashing it and several hours on the forums and such and while it worked wonderfully for some it was impossible for others. I did a considerable amount of digging and came across a YouTube channel, Physics Anonymous, and he summed up pretty much all the errors I was having and went back to Mach3 but rewrote an amazing interface especially for touch screen users which I am as well. It hasn't been complete smooth sailing but I am progressing quite nicely once again at the very least. I really like the interface he wrote and highly suggest anyone on Mach3 take a look.

I picked up a mini Lenovo I5 PC off Amazon as a refurb and it has also been really amazing and I have used several of the other Atom based systems and while they work this thing is really snappy to say the least.

I now had to get the base and damn it was a chunk. 23.5x42.5x1.0 is what I came up with and yup right off eBay.
I then went a step further and added a pair of 1x7.5x31 slabs on top of the base plate to give me a fixture plate to drill tap and add pins in both 1/4 and 1/2 which will be critical to the plates I need to make off the bat.

Step 10: It Lives!

Well the moment I had been waiting for finally arrived just a few weeks back and I have to say it was really exciting. I got the big Boss lady out there for the inaugural "First Motion" and it's been pretty exciting from there.

That being said let me tell you the real work has just begun in many ways. I have dabbled in Fusion 360 for some time but now I am outputting files that make a pretty meaty CNC machine fling a cutter spinning up to 18,000 rpm's around and that can be a bit daunting at first.

CUT AIR!.....that's they key and even then it goes awry at times...I zero my Z about 2 inches above everything now to make sure I have my WCS in the right place and not Saturn WCS or Jupiter WCS and it has gotten quite a bit smoother.

I am also loving Fusion 360 more and more every day and the independent content and the YouTube videos coming out weekly from the F360 folks, with Lars C coming back just yesterday, is simply amazing. NYCNC is priceless as are a whole host of others I could go on naming for pages.

I am working up to a pretty significant drilling and tapping operation on my embedded fixture plate as well but thread mills are very pricey and tolerances pretty exacting so I am stepping up to it very carefully. Again an impossible task without Fusion 360 and most importantly the community of F360 users and dedicated content providers. My fixture plate for example has some of the CAM operations from NYCNC's website project D/L's I turned into templates as he demonstrates and then studied and modified or just straightaway incorporated into my Setup which is an absolutely amazing tool in itself. I'm not quite comfy enough even as I write this to cut and drill/tap but I am refining all my recipes in test and should get it done very soon and will update and share the results here.

Step 11: Final Thoughts...Sorta

First off there are no real final thoughts on a project so thankfully this one will go on for quite some time and I will revisit this as it progresses and I get a better handle on actually using it.

That being said I am also working on a 4th Rotary axis in C, horizontal rotational perpendicular to the live spindle and the above plate will also hold a quick change for standard lathe tools as well as a removable 3D Printer head and Laser mounted on a slide with a ball screw. I am also currently fitting a flip down edge finding/Z probe I will set a tool offset on to make setup easier without popping the probe in and out all the time. Also note I have set aside room at the back of the unit in front of the control box to eventually add a tool rack for an auto tool changing spindle. I spent a fair amount on this but not nearly what something of this capability would cost but did not want to go too crazy right off the bat so I will evolve into the ATC but I did plan for it down the road.

I have right about $5000 in this so it was not a cheap machine but I will add videos along the way that clearly demonstrate its a very capable machine and given that not something you could get for $5000.

This may not be a step by step recipe for building this particular unit but that's not really the point here as how I got started with this was seeing something that inspired me to contemplate, Design and finally build and all along the way I was learning new things and expanding on my overall knowledge base and that's the real beauty of a project like this.

I also wanted to add some photos of the Physics Anonymous Mach3 screen which is absolutely the best I have ever seen so check out his channel and D\L the screen set and if you like it as much as I do then drop him a few bucks via his Tip jar.

I also just can't say enough about Fusion 360 and how much I am really enjoying diving into the depths of it's capabilities. I HIGHLY recommend anyone still holding out on learning more about it to just sign up and get started. The fact that it is free to use for us Makers is just absolutely staggering and the effort they have put in especially this year with all the video training content directly from AutoDesk while we are all going through this has truly kept my brain solvent and I am soooo grateful let me tell you.

I will be super glad to share any of my insights on the stuff I have put forth here so just drop me a comment or something and I will be glad to answer any questions.

Be Well and Be safe!


Step 12: Work Continues

456 drilled and tapped holes with .375 upper bore for the use of location pins!! This was a real challenge with all the various operations. I spot drilled and then opened up an undersized hole to depth and then actually went with a boring operation in F360 to dial it in a thou or two at a time so I could avoid a dedicated reaming operation as I don't have a .501 or so ream. All in all it worked out pretty well so I am now ready to actually make some stuff and project 1 is going to be a Collet Holder for sure.

I am also seriously rethinking the spindle as these tool changes and height measurements and the overall limitations are pretty frustrating. I am thinking a BT30 at the moment but there are several options out there.

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    1 year ago

    This is incredible. Thanks for writing this up!!


    1 year ago

    Beyond intense, but so nice to see. Well done, thanks for sharing!