Starting from sub-zero

[eternauta3k]

Hi all,
I've been wanting to build a CNC router for a while (actually, I've been between a router and a foam cutter). Today, I found free plans for the JGRO machine so a few questions came up:
1. Somewhere (maybe on another forum) I read that it required basic woodcrafting skills. Being 14 and not much into that (although I do make R/C airplanes) I don't think I have that kind of experience. My dad, however, may. What do you mean by those skills?
2. Interpreting the plans
I haven't had a deep look at them yet but they seem complex (for me, that is). Where should I start, or where should I ask someone where to start :P?
3. What can I do with it? This isn't that important, but I'd like to know the possibilities.

Some books to learn these things would be great (instead of asking you all the time

Thanks in advance,
Ignacio

[gilligan]

I'm guessing your going to school if your school offers a shop class i would take any courses they offer. Nothing is better than education. Talk to friends and family you maybe surprised on what kind of help they can be. The biggest part is being patient somtimes you'll run into a hard spot that will stump you for a long time and after you figure it out you'll be thinking why didn't i think of that right away. The best advise i can offer is read all you can in these forums and surf the web they are of the biggest help to me. For the what you can do with it depends on how you make it if you make r/c planes you could design you plane on a computer and have the machine cut it out which is convient if you crash a good plane design so you can make another one or just make modification to it.

[eternauta3k]

No, we don't have a shop class... still, my dad's company has quite a few tools, some people with experience and I know a surplus printer/scanner/etc. parts shop.

if you make r/c planes you could design you plane on a computer and have the machine cut it out which is convient if you crash a good plane design so you can make another one or just make modification to it.

Amazing...
By the way, can the that router cut metal? Cause if it can, I've got some uses in mind (making engines



Okay, that was a bit ambitious

[chuckknigh]

You build airplanes for a hobby, and you're worried about this?!

For the most part you need to be able to cut wood/MDF, and have the resulting cut be square and straight. Having it end up the right size helps, too. It also involves some minor "machining" type of work, like drilling holes with reasonable precision.

I didn't build a JGRO unit, but the basic construction is pretty similar on all of them.

These machines are pretty simple, mechanically...take a look around this site. LOTS of pictures. You'll notice just how simple they really are, when you start really looking.

Look also at the solsylva (sp?) machine...it's inspired. One of my current favorite designs, primarily because of the fully supported rails. Supporting the rails addresses a LOT of the problems with the other designs.

http://solsylva.com/cnc/1aplanshome.html

-- Chuck Knight

[eternauta3k]

You build airplanes for a hobby, and you're worried about this?!

Well, model airplanes, I don't think they're harder than doing this
Regarding the plans on the link, it seems like a nice machine but adding $30 to an already expensive project, while it could be done for free...
There is a Home Depot here, problem might be looking for non-metric stuff... also, I'm, not that precise while cutting ¬_¬

Update: My dad needs it to have a precission of 0.01mm, for making PCBs


By the way, turns out there's another Argentinian building a router (peu)

[chuckknigh]

I didn't mean for you to *necessarily* buy the plans...just to look at the finished machine, and get creative. He is a member of this forum, though, and he would probably appreciate the purchase.

His use of fully supported rails is a VERY good idea. Sagging and sway in the pipe rails is one of the primary weaknesses of many of the homebuilt machines...this is a very elegant way to address it. Simple solutions are often best.

-- Chuck Knight

[eternauta3k]

Ok, my main issue now is where to start. Peu seemed to design it with some CAD program, and afterwards built it. However, I think he had ordered some parts before having a finished design. I'll PM him asking about the design, and see whether I can come up with something.
I just hope there's a hardware shop nearer than the home depot.. anyway, I'll see if I ask my dad for books on mechanics and design.

[sol]

Originally Posted by chuckknigh ...it's inspired

woohoo! Everybody loves a compliment
As Chuck said there are tons of ideas and pictures out there, mixing and matching ideas from what you find is often the best route to follow if you have the time to trial and error through the design.
A CAD program is unnecessary and can slow down the process for some of us. Working with real parts or cardboard and hot glue can help find problems and solutions that are not obvious in the virtual realm.
The 0.01mm precision will be tough to hit with a machine that has any wood in it and without a reasonably well equipped shop that target becomes unrealistic.
Maybe consider starting with a super cheap machine made from printer parts, do not worry so much about accuracy at first, just become comfortable with the concepts. I really think you will be disappointed if you try to start with a 0.01mm accuracy machine unless there is somebody with knowledge and tools who can help.
Good luck!

[eternauta3k]

I liked the idea of starting with a simpler machine. I found a local distribuitor. I thought about using a CAD program because I didn't want to spend lots of money to test things which might, later on, not fit together.
By the way, the distribuitor has all the things peu bought from the USA.. let's see whether they're cheaper (I hate websites which don't list prices!!! )
By "reasonably equipped shop", you mean with reasonable equipment (and what would that be), experienced people or both :P?

Edit: I just thought... peu's first router had the accuracy I want. Is it possible for me to achieve it too?

[PEU]

Hola Ignacio,

Forget about local shops, I asked prices for linear rails and they are simply NUTS, about u$d600 for a 500mm THK rail with a single block. Same with motors, same with ballscrews...

My suggestion if you want to start cheap, build a simple MDF (fibrofacil) and tubes Jgro router, some spare steppers from surplus laser printers or copiers and learn the trade.

Then you can make a more precise one so your dad can drill PCB's

Or, if dad helps go for the precise machine, but let me tell you that precise does not come cheap...


Pablo

[chuckknigh]

Since you mentioned PCB routing, this is a planset for a machine specifically designed to route PCBs.

http://www.crankorgan.com/brute.htm

Sorry about linking to *his* site, guys...but it's a perfect answer for his question. This machine is designed around routing PC boards...it's simple to build, and according to all reports it works quite well. In fact, many of us who are homebuilders were directly inspired by one or more of *his* ideas and designs.

Show the pictures of these machines to your dad, and realize that this one makes extensive use of extruded aluminum window channel. It's "commonly" available in the USA...not sure if you have something similar in your country. It's a large extrusion (4x6" in cross section, for the extrusions I have in the garage) in the shape of the letter C...lets you use simple parts to slide around on the extrusion. The sliding parts are plastic, and fit *around* the edges of the extrusion. Viewed end on they resemble a letter H.

That should be enough of a hint for you, without giving away all of his secrets...

Like I said earlier -- don't be afraid to get creative. There is a wealth of information and expertise on this site, and we're all VERY willing to share it.

Seriously, though, here's some free advise -- build a simple and small machine first. You can reuse the expensive parts like the motors and circuitry on machine #2, and use the smaller machine to build the precision parts for the bigger machine. Your biggest enemy will be flex...and it's easier to keep small machines from flexing.

-- Chuck Knight

[eternauta3k]

If I do build one, it'll be a smaller one as you said. I can't buy used parts from abroad because my dad says they can't pass through customs. Additionally, it either costs a lot from multiple shippings, or it's a single one and I have to hope parts will fit. I'll see if I find a local solution (MDF and tubes like like peu said), or drop it. I really don't get how I'm gonna get the bearings though (maybe it wont use any)

Now I better start reading a book to understand the plans... someday...

EDIT: WAAAIT... we can buy used things of this kind... it's used legos that he doesn't know how to get through...