# CNC Machine - for home-building aircraft

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#### FritzW

##### Well-Known Member
Log Member
It's a lot easier than it looks

#### Rienk

##### Well-Known Member
Ah-hah! That's where we ended up with a headache.

One of the goals of the machine was not just to cut flat sheet but eventually carve mold plugs for the many fiberglass fairings that are to be made. So having something that was reasonably level for that purpose was important to me.

That said, yes, a machine for sheets isn't going to be as critical for flatness now is it? So maybe it's a chicken and egg thing and you have to pick what is more useful at the moment.
Getting the rails level and straight enough so that there is no twist isn't that big of a deal - and thus 2.5D (carving three dimensional plugs from one orientation) is completely feasible. Back when we made our table out of angle iron (which isn't straight) we came up with a simple adjustable way to straighten it. There are more elegant means now of day; and of course, better extruded profiles to start with in the first place.

I think a 'flat pack' airplane design would be the perfect way to get people to learn (and be comfortable with) their new CNC routers. Some then might move on to designing their own 3D plugs and such (though that lends itself primarily to composite design).
But getting to the point that you can design a 3D plane - including jigs and fixtures - from sheet goods, is all on the design and software side, which very few are going to have the knack for, let alone get proficient.

But who knows that the next Van or Rutan might not spring from such a humble beginning.
Which is why I would encourage each of you to let a 'kid' hang out with you once in a while during your design/build process. None of us got started in a vacuum, and no one else will either - pay it forward!

#### 12notes

Log Member
I just noticed the CNC in post 31 now says buy one, get one free. So if two of you get together, there's your sub-$3000 kit. #### FritzW ##### Well-Known Member Log Member ...and it says free shipping #### Rienk ##### Well-Known Member I just noticed the CNC in post 31 now says buy one, get one free. So if two of you get together, there's your sub-$3000 kit.
Oh, you got my hopes up!

But if you click on the details of that offer, it's not two CNC router machines... what they include for "free" is a Cutting Plotter.

#### etard

##### Well-Known Member
No, indeed that IS buy one get one free! If you add quantity 2 to your cart then you will see the buy one get one free discount when you go to checkout.

I wish I was in a better position to take advantage of this deal...

#### Rienk

##### Well-Known Member
No, indeed that IS buy one get one free! If you add quantity 2 to your cart then you will see the buy one get one free discount when you go to checkout.

I wish I was in a better position to take advantage of this deal...
You may be right, but that's not what the "fine" print says. I have sent them an email to clarify.
Also notice that they will ship it to the nearest port. Presumably, it is up to the buyer to pay for customs/import duties, and shipping from there.

#### harrisonaero

##### Well-Known Member
Having purchased quite a few things from China, remember the old adage TANSTAAFL.... "There ain't no such thing as a free lunch."

The Chinese know how to make money, and that means making your machine as cheap as they possibly can. Most likely you'll find this show up in the wiring and electronics and will be in for a real surprise when the smoke starts to escape. I know this from personal experience and it has really cost me a lot of time and money. Especially compared to my old US made ShopBot that wasn't fast or rigid but was dirt simple and very reliable.

So from my experience buying equipment from China is like trying to use a auto engine in an airplane. Plan on a lot of tinkering to get it to work right. And what looks like a good deal when you start will almost inevitably cost you more in the end.

(have owned CNC routers for the last 15 years)

#### ScaleBirdsScott

If one got a cheapo chinese router that nonetheless had solid enough framework and only needed re-done electricals... that's what, maybe $1500 if you redo all of it with moderately good steppers and a g540? Maybe less? I'm more inclined to say build one from scratch but its would br kinda nice to have the frame squared amd ready to plug into... The CNCRP kits look close to that but there's still lots of bolts and squaring and assembly work to them. #### WK95 ##### Well-Known Member Having purchased quite a few things from China, remember the old adage TANSTAAFL.... "There ain't no such thing as a free lunch." The Chinese know how to make money, and that means making your machine as cheap as they possibly can. Most likely you'll find this show up in the wiring and electronics and will be in for a real surprise when the smoke starts to escape. I know this from personal experience and it has really cost me a lot of time and money. Especially compared to my old US made ShopBot that wasn't fast or rigid but was dirt simple and very reliable. So from my experience buying equipment from China is like trying to use a auto engine in an airplane. Plan on a lot of tinkering to get it to work right. And what looks like a good deal when you start will almost inevitably cost you more in the end. (have owned CNC routers for the last 15 years) I've worked on some electronics in the past. Suffice to say, I don't use Chinese designed parts anymore. Though, I'm fine with most things that are designed outside China but are only manufactured there. #### WK95 ##### Well-Known Member If one got a cheapo chinese router that nonetheless had solid enough framework and only needed re-done electricals... that's what, maybe$1500 if you redo all of it with moderately good steppers and a g540?

Maybe less?

I'm more inclined to say build one from scratch but its would br kinda nice to have the frame squared amd ready to plug into...

The CNCRP kits look close to that but there's still lots of bolts and squaring and assembly work to them.
And that's how they hurt themselves. Sometimes, an otherwise well designed product is messed up by poor manufacturing simply to save on costs.

#### VAPORTRAIL

##### Well-Known Member
Being someone who can usually figure out a way to justify just about ANY tool purchase, this seemed an interesting thread.

But even I can not make a case to buy/build/acquire a system like this for a homebuilt aircraft. (Aside from it would be really cool to have)

Unless the goal is mass volume kit production, how could any CNC machines and the required computer hardware, software and programming skills and time possibly benefit us as homebuilders?

#### ScaleBirdsScott

##### Well-Known Member
If you're scratchbuilding to your own design and have no templates to go by, and you have patterns in CAD already, it's a lot faster to just go cut a sheet on a router than to attempt any kind of hand layout; unless maybe you've been cutting tin for decades?

With our Hellcat, my dad and I had a few situations where we had a part and bent it wrong, or the original pattern was off, or the holes got buggered, or my dad put a drill bit into the metal, or I diddn't account for k-factor in my bend and the flange was short... and having all the files already in the system it almost always just required loading a sheet back on the table, finding the right code, and punching out a new part which could then be bent and installed. Or if the part needs changing, then its a simple matter of adjusting the CAD geometry then re-running the CAM and then back to running the file through some new aluminum (or wood or what-have-you)

For some super simple parts there's more speed in just pulling out the shears and going to it, yet I still like letting the CNC make the cuts because they will come out clean and accurate.

Another feature is that at some point we'll be using the 3D machining capabilities to accurately carve MDF and/or foam to make fairings with more detail and precision that the average person (myself included) would attempt by hand. I know how to carve and sculpt a 'looks-like' model from dense foam by hand, did it for 3 years at RISD, and I'm super keen to let the CNC do it for me on this airplane project.

If you're buying a kit there's zero benefit. If you have a good set of plans there's very little benefit. If you have only an idea in your head, it's the closest thing we currently have to 3D printing your own aircraft.

It's one of those things where either you know the technology already or want to learn the technology for your own enjoyment, and that's at the heart of homebuilding for many already isn't it? If it was just about having an airplane there's plenty of used GA aircraft out there still. But it's about the process and for some the process of introducing computer controlled tooling is a hobby unto itself.

For me I'm already getting ready to build a CNC benchtop mill for making parts from billet aluminum and steel. And I'll be converting a small lathe after that. It started with a 3D printer and having access to some toys in college, and now it's a full-blown hobby. Building an airplane you designed yourself, on a machine you built yourself, is just part of the whole package.

#### FritzW

##### Well-Known Member
Log Member
...how could any CNC machines and the required computer hardware, software and programming skills and time possibly benefit us as homebuilders?
Why don't you ask "how could the time and money spent on buying a TIG welder, and learning how to use it properly, possibly benefit us as homebuilders?" The same could be asked about composites.

But to answer your question: What about a MiniMax or Legal Eagle wing that could go from "plywood coming off the UPS truck"" to "ready for fabric" in a weekend. We're not there yet, but **** near.

You remind me of the guy who asked Benjamin Franklin "what is the use of man flying in a balloon". (the one where he answers "What is the use of a new born baby")

#### rtfm

##### Well-Known Member
Hi,
I'm good for 2D CAD only. The 3D stuff has be completely beat. But I have a guy who turns my flat drawings into beautifully rendered masterpieces. We are currently in the final stages of working out the kinks in the latest version of my project. I will then receive 50 or so templates which will need to be cut from 3mm MDF. I could cut them by hand, but that will introduce an unacceptable degree of variation. To have 50 templates cut commercially is so expensive that it will actually pay me to buy the hardware from openbuilds.com and build a CNC router, which can be converted to a CNC hotwire cutter so that I can cut the foam also.

And then, when it comes to building the wings, the tapered wings can also be cut using the hotwire. I'll end up with really accurate fuse templates and foam, and great foam panels for the wings. And zero mess.

What's not to like?

Duncan

#### quickcut

##### Member
Just completed my 600* 900 router. Going to use it to cut aliminium ribs,etc for a zenith 750 cruiser. There is a great website in the UK with loads of designs for machines . Not sure if I can post a link though.

#### WK95

##### Well-Known Member
You remind me of the guy who asked Benjamin Franklin "what is the use of man flying in a balloon". (the one where he answers "What is the use of a new born baby")
As exercise equipment...

#### cheapracer

##### Well-Known Member
Log Member
Having purchased quite a few things from China, remember the old adage TANSTAAFL.... "There ain't no such thing as a free lunch."

The Chinese know how to make money, and that means making your machine as cheap as they possibly can.
I once bought a new small Tucumseh engine for a go kart I made for my kids, it was very cheap and it was a total piece of crap (true story) - so following your lead, everything made in America must be rubbish!

Now we all know that's not true of course, America indeed makes some crap, but they also make lots of medium level quality and of course, they also make lots of the finest quality stuff in the World.

And so do the Chinese. Oh yes they do.

While some will buy a $500 Chinese built machine against a$1000 American machine and take their chances, if you have a choice between a $1000 Chinese and$1000 American, you will take the American one all day long. Point is there is no market for those medium and fine quality Chinese machines outside of Asia, so all you see in your market is the cheap stuff.

Unless you have a specific one time use or short life cycle for it or as some suggest, willing to make improvements, don't buy cheap crap - which country it is made in has nothing to do with it, you are the Consumer and the decision is solely yours.

#### Rienk

##### Well-Known Member
I once bought a new small Tucumseh engine for a go kart I made for my kids, it was very cheap and it was a total piece of crap (true story) - so following your lead, everything made in America must be rubbish!

Now we all know that's not true of course, America indeed makes some crap, but they also make lots of medium level quality and of course, they also make lots of the finest quality stuff in the World.

And so do the Chinese. Oh yes they do.

While some will buy a $500 Chinese built machine against a$1000 American machine and take their chances, if you have a choice between a $1000 Chinese and$1000 American, you will take the American one all day long. Point is there is no market for those medium and fine quality Chinese machines outside of Asia, so all you see in your market is the cheap stuff.

Unless you have a specific one time use or short life cycle for it or as some suggest, willing to make improvements, don't buy cheap crap - which country it is made in has nothing to do with it, you are the Consumer and the decision is solely yours.
For the most part, I agree.
However, the economics of it should be different. With the cost of labor in China still so much lower than in the US, any labor intensive product should be possible to make less expensively in Asia than in the US. The trickle down effect can likewise make raw materials less expensive. That doesn't mean that they are, or that China doesn't put out a lot of crap when they don't have to - but that may be dictated more by importers than the manufacturers (e.g. Harbor Freight).

One of our businesses makes telecommunication towers. I have visited factories all over eastern China, where some are made in factories with dirt floors and poor manufacturing conditions, while some are facilities as/more cutting edge than many in the US. It's no surprise where the markets are, for those different levels of quality (developing countries, and NorthAmerica/Europe - respectively).

There are certainly Chinese manufacturers able/willing to make products - such as CNC machines - to the standards expected in the 'mid' to 'high' quality markets expected in the US. Unfortunately, importers such as HF generally cater to the extremely budget minded - and there are a lot of people who are willing to buy a "cheap" (not just 'inexpensive') tool because there is no other way they can afford it otherwise.
I just wish there were an importer that would bring in quality products, taking advantage of the labor rate differential - not the willingness to use cheap materials and minimal standards.

For example, we have both a Kern cnc laser and a Chinese import. The cost differential is literally exponential - but the Kern uses a laser head (Coherent) that is 50X more expensive than the glass tube in the cheaper machine. The Chinese machine does a decent job, but is a lot fussier and needs more TLC than the Kern. But for someone just getting started, I would have no problem recommending "certain" imported machines.

We hope to set up FabLabs in all our region's middle and high schools (with cnc laser, cnc router, 3D printers, vinyl cutters, etc) and the only way we are going to be able to do so is to partner directly with Chinese manufacturers willing to produce quality machines to our standards, at a competitive price (using the overall labor differential).

Any Chinese manufacturer that can make equipment to the same standards as Haas, Omax, Kern, Objet, Tormach. Flow, 3D Systems, etc. - and do so at a significantly lower price - needs to partner with some sort of North American importer/distributor, and they should be able to do very, very well.
(but private label with American names... some of these Chinese companies still don't understand the American mindset and way of doing business).

Getting off my soapbox now...