Seeking recommendations to assemble a complete CNC kit

Yeah, sorry! I couldn’t get past the wheels on the machine part :rofl:

And there are people on this forum doing it too!

Best advice from my sorry butt is as follows (and the numbers are the order of importance);

  1. Spindle (get the nicest one you can afford because this is the heart of your system and avoid the hardware store router conversions)
  2. Motors (NEMA 34, the lesser system with NEMA 23 would work better with the hardware store router conversions, see #1)
  3. Size of machine (AvidCNC is pretty expandable but I wouldn’t put a NEMA 23 on any machine over 4 feet in either direction no matter the choice in spindle)

Minimum spindle I would go is this model; GMT Spindle Motor Air Cooled 2.2 kW (3HP) 12000 RPM ER25 for CNC Router Mill | eBay

Call the factory about the cabling.

If you dig on eBay you might find the 24,000 RPM version of that GMT spindle and it would work with the AvidCNC VFD. I think that COVID pretty much killed that market though. I see none of the spindle I use to see on ebay still for sale.

Thanks a bunch, I appreciate all the feedback. I am a fan of ‘buy it only once’ (IE avoid ‘will upgrade later’ whenever possible) but trying to stay within certain constraints. I have a couple other questions:

1 - other than maximum ratings (IE stronger motors, more power supplies, etc) what are the benefits of the NEMA 34 kit over the NEMA 23? All the IO and general capability seems the same; the main difference I see is just the power ratings of the motors that are allowed/compatible with the system. If I’m doing just wood cutting, is the higher rating really necessary or just a comfort zone of never really putting any strain on the system?

2 - any particularly recommended dust collector/management?

You are asking great questions. Spindle is the most important thing so wait until you can afford that and I promise you, you will be much happier!

NEMA 23 provide lower side force to the tool during the cut. The material will push back against the tool and if that exceeds the motors output it will stall and you will lose steps. So not only does side force deflect the tool but it also puts a strain on the motors in the axis.

NEMA 34 is “about 2.5 pounds of force” (not the 75 pounds some idiot put earlier… :stuck_out_tongue: and yes that idiot was me, I got the numbers from my metal machines by mistake, cuz’d a ruckus)

NEMA 23 sounds like (estimating ) about 1.8 pounds.

Ooh, yeah. About that. Uh, I have a Grizzly 1hp wall mount with a 4" tube used exclusively with my 3hp S30C spindle. Works great.

Really the dust manifold is the biggest factor in antiquate removal of dust (some call it a dust shoe). The maximum sized for the orifice should be the same size as the tube it is attached too. Any larger and you lose velocity and thus effectiveness. Too much smaller and the pressure drop behind the dust manifold will cause the material will fall out of the stream and collect on the bottom of the tube.

Dust manifold design is a hot topic in the DIY CNC world :wink:

Got it, that’s a value I wasn’t sure how to quantify until now; realistically what does it mean, how do you properly combine/estimate all the force factors? I know enough about this stuff that I’m dangerous :rofl: Plenty of DIY experience with hand (and some table tools) under my belt, IT professional so CAD software and other technical info is easily digestible, hobbyist 3d printer so the terms and concepts are all familiar, but trying to launch myself into a small business to serve a niche in one of my other passion/hobbies with this is admittedly leaving me a strong feeling of ‘jumping in the deep end’ sensation such that I’m trying to find out what I don’t know I don’t know and temper my daydreams/ideas with realistic expectations.

IE The NEMA 23 is rated at 200 IPM with a ‘rapid’ rate or 400 IPM. If we look at a tool speed of 16000 RPM (which both the 4hp spindle and the Porter Cable 7518 are capable of without maxing out the tool motor), how much force do I need to worry about when dealing with wood? Will that 1.8lbs drive the up to the 400" travel rate without issue?

Also, how much depth do you usually do in a single pass with this kind of lateral force and tool speed: 1/8", 1/2", more? For the work I’m planing it’s all simple line cuts of the whole depth (5/8" is the current spec, need to run a couple test jobs to see feasibility) through the work piece (minus the tabs needed to hold the piece in place) to get the final product, 200 IPM would make pretty quick work of the job if each pass was a good depth, but I wouldn’t want to push the cutting head so hard that it either stalled or snapped.

Cool. I’ve seen a few posts about some folks’ methods for dust collection systems, with the table I already had in mind to build I could fairly easily attach it to that and have a swing-arm handle most of the work; I built a rig for my VR kit, so that’d be a similar task.

I don’t see any ready-made dust manifolds/shrouds on the grizzly site though, or even here on AVID. Where would be a good place to look at options for those?

I have one for ATC; SUBNOIZE: 10 Tool Carousel, Tool Length Sensor and Dust Hood

There is another guy 3D printing them somewhere. I tried the plastic thing and it melted on me :rofl: so mine is 0.25 steel plate laser cut with a lower part 3D printed that doesn’t come into contact with the spindle. That was my most expensive crash :roll_eyes:

Most people use the term “dust shoe” because the manually take it on and off i guess so search for that.

I use HSMAdvisor here;

There is also this one that all the woodies love;

The 1.8 pounds of force is at the side of the tool in the spindle. Each axis would have more power associated with it because they are directly connected to the motor. It’s the transition from one axis to the next and to the next and then down that lever created by how far down the Z axis is extended that adds up to give you that 1.8 pounds “theorized” maximum cutting force.

Yep, this is the part where you gotta get one of those calculators. I led you to water, now its your turn :horse:

Also, look up “CNC nuts” on youtube. he has some good videos on the topic.

Nice! I’ve seen a few tool swap kits and that’s definitely a nice feature to aim towards eventually :slight_smile:

Thoughts on this one?

Will do, thank you very much for your time and all the information!

The dude posts on this forum. His system works for him and he selling them so you can ask around about how effective they are.

I will tell people getting into CNC machining that owning a good 3D printer is a requirement now. Mostly for jigs and fixtures but also for things like dust shoes and the like. That said, I wouldn’t be printing in ABS or PLA for that thing. Probably CPE+ would be better.

A router and NEMA 23 combo is OK but I certainly wouldn’t recommend it if time = money.

If you’re ever even thinking of going to a spindle, start with the NEMA 34 system and a router. It’s much easier to upgrade to a spindle and keep the router around the shop for other use than to replace the entire electronics kit and motors - and then do what with them?

This is something I’ve been trying to weigh the pros/cons over where the biggest blocker from going that route is my budget/finances to get it off the ground; $10k is my pretty firm limit and the NEMA34 would go over that by about 15%.

Given that this would not be my primary income stream, that max level production speed is not top on my priority list. Any particular reason why the 4hp spindle (the assumed swap-in replacement for a consumer grade router motor) and NEMA23 electronics would be a bad pairing, other being able to push things as fast as possible right out of the gate?

If this project/business idea of mine goes well, I could easily see using proceeds to construct a dedicated workshop just for CNC work and getting a second machine (and NEMA34+AVID spindle from the start) to increase production by more than double rather than incrementally through an upgrade to the existing table, though that upgrade to original equipment would likely come later for standardization of equipment.

If you are not sure if this business idea will be able to pay for itself and your budget is limited, perhaps you should look at a different machine? If you are not really concerned with high production speed there are lots of good options out there. Since this is an Avid forum, I am reluctant to post links directly to other CNC manufacturers. I personally got into the CNC world with a Shapeoko 3 before I purchased an Avid. It allowed me to learn a bunch. I come from an extremely similar background (IT pro, experience with CAD, been 3D printing for years, bought first machine mostly for hobby with some money making potential). I have since upgraded my little Shapeoko 3 myself to use linear rail and a water cooled spindle. It is basically a DIY version of their Shapeoko Pro. I would love to get the recently released 4x4 Shapeoko 5 for fun just to see how far they have come. Looks like a pretty slick machine.

Don’t get me wrong, I am mostly happy with my Avid Pro. I have not been impressed with Mach4 (the control software Avid ships with their machines). I have a Pro 60x120 with a custom ATC setup using the CNCDepot S30 spindle. We use it in a custom cabinetry business. There are other good options out there for people in your situation. I would not buy an avid 4x8 with anything less than the Nema 34 motors and a 2.2kw spindle. The 4hp kit from avid is also very good for a plug and play setup. I also do not recommend any v-wheel based machine like the standard avid kit. V-wheels build up dust and chips from cutting and are a pain to maintain. They are also a significant step down in rigidity from linear rail. This is especially noticeable when you are trying to make money. In my opinion, it will be essentially impossible to get a plug and play machine that is noticeably better than something like a Shapeoko 5 for less than $10k. Your only limitation there is 4x4 vs 4x8. You can still put 4x8 material through a machine like that by tiling your work.

ThinkboxTech has a pretty good argument for your situation. I debated the same merits he brings up before buying my Avid machine. In fact, I debated for years before purchasing a CNC.

For me, I had the money and I simply KNEW I would find ways to utilize a CNC to make money. So between having that confidence and already having the money, I made the decision to preemptively go the Avid route.

I’ll comment on my dust manifold since you referenced it earlier. It works incredibly well and is super functional with the magnetic attachments. There has been quite a bit of interest in it through my Etsy store. I don’t have a version developed for a router, just the 4HP and 3HP spindles (8.7HP currently in development). If you end up going with a router and you’re looking for a good dust extraction setup, hit me up. I could take a look and maybe develop a solution for a router.

This business venture would be running off my own land/property, so the typical expenses of rent/utilities/etc are masked a bit by being run at home, and the markup for what I’m producing would be enough to pay for this equipment in ~100 units (if all proceeds go dedicated to it). The only fear of insolvency about it is if I have wildly misjudged the market gap I’m trying to fill . That being said, a capable CNC is a valuable asset and I’ve already spoken with one person where an idea was floated to contract out the major stock cutting work that they’ve been doing by hand. So even if my own project is a slow/low-volume burn idea, I am definitely interested in finding other things to keep the machine in use.

As for why I picked AVID, I did some digging around and while I’m sure it wasn’t an exhaustive search that covered absolutely everything, there seems to be a pretty sharp jump from ‘hobby CNC’ (with things like Maslow and Makermade) to true ‘production shop grade’ stuff like AVID and no real middle ground between the two for the size of material I’m looking at working with. Tiling would allow me to get a smaller machine, but that introduces a lot more manual labor per piece being cut that I prefer to avoid.

Yep, this is where I’m at. I have enough cash in hand to put together a solid starting kit and if things go well I could expand what I’m doing (and retrofit/upgrade the first kit later). I do like your dust hood, would definitely be aiming at that one if I take the plunge, was hoping that the Porter 7518 router motor/head would fit between the channels like the 4hp motor would but having a hard time finding dimension specs on some things.

Explain this one a little more? looking at both the AVID Pro and Standard 4x8 kits there’s no mention of wheels, just linear rails and bearings.

Technically, the standard avid machine isn’t using v-wheels. They use custom linear carriages that each hold several standard radial bearings that ride directly on a piece of steel bolted to the gantry or side rail. The principle is the same. It is a wheel riding on an exposed surface and they tend to build up junk which can cause premature wear, surface finish and accuracy problems. They also are not as strong and have more slop that a linear rail with carriages. Avid’s implementation is probably slightly more rigid than a standard V wheel. Here is a picture I pulled from Avid’s installation instructions for the standard machine:


VS the pro machine that uses linear rail with carriages:


As a general rule, linear rail with carriages are more rigid because of their design. They also can have wipers built in that prevent debris from getting into the bearings. Another notable difference between the standard and the pro is the Z axis. The standard has an exposed lead screw and the pro uses a covered ball screw.

If you are confident in your ability to get a return on your investment and most of your work is larger than 4x4, then I would be even less likely to recommend anything less than the pro 4x8 with nema 34 electronics, 4hp plug and play spindle with the mount, homing sensors and the corner finding block. That comes out to about $13k from Avid. That doesn’t include your machine base, dust collection, control PC, tooling, waste-board and any workholding. We went with a DIY vacuum table for our machine. All in on our 5x10 pro (excluding the ATC spindle and setup) was somewhere between $25-30k after adding all that stuff plus some safety related bits. We have set up ours to do more production than it sounds like you are planning to do right now but I would still plan on spending 25-50% in addition to the cost of the kit in supportive stuff.

Thanks for all the feedback and additional info! Based on everything I’ve heard I feel confident that the kit I’ve got planned will be sufficient to do what I want. I’ve priced out everything except the 4" hose for the dust control system, the materials to build the table I plan to put this on, scrap surface, and minor bits needed to rig up a vacuum hose swing-arm.

So the Standard 4x8 kit, NEMA23, proximity sensors, corner/z kit, Porter 7518 3.25HP router, 7518 mount and tramming assembly, CAM software, AVID software, 1.5HP cannister filter dust system, woodworking bits, and ‘dust shoe’ budget - that puts me right at $10k (before tax & shipping).

The PC and any other bits to manage the system is a trivial thing, my household is tech heavy so I’ve got equipment to spare unless there’s some high-end workstation requirement to run the controller software. If that were true I can still swing that without extra cost, I would just need to shuffle a couple systems around.

It’s not quite what folk have recommended (and believe me I have heard you, any expansion of the shop and I can aim higher/more-beefy), but for the resources I have available to me right now I feel this can get me started and get the work done without putting me in debt.

I have more money invested in ISO30 tool holders than I do the base PRO60120 I purchased back in 2019. That is what an ATC does to you, puts you in the poor house :rofl: