A bit torn; looking for some input

[Jesse B]

Well I've been researching this topic for a few months now, and I'm getting close to making a decision. I've got all of my electronics picked out, so that portion is completely covered. The machine itself, however, I'm still a bit undecided on about what to do.

I'll just make it clear right now that I a) AM on a budget, and I've got to pay for school and whatnot, and b) Will not have the money to do this until summer.

Anyways, this all started with seeing some DIY CNC Machines on Instructables. I figured "I bet one of those things would be pretty nice to have around". I started noticing that people were complaining about precision, unreliable electronics, etc. After a quick Google search, I found this place, among others. In the last few months I've learned an astounding amount about CNC. The problem with this new found knowledge, however, is that it entirely destroys my original plan. This is good I suppose, as it will save me money in the long run.

I was originally planning on building my first machine (as mentioned above), but have come to the conclusion that this is not recommended. I figure that a kit would be a much better choice for my first machine. Deciding on a kit is my main issue at this point in time. Widgitmaster's Midi Router looks pretty much perfect for what I wanted to achieve (see below); unfortunately, it appears that they have discontinued production. Crap. So that leaves me entirely lost. I've found what appears to be a pretty decent looking machine over at Modular CNC, and the kit is fairly inexpensive as well. I was looking at the CNC Mini Milling Machine Kit, which has a maximum travel of 6" x 4" x 4". I'm worried this will be a bit small, and limit what I am able to do.

So with the above mentioned, I'd appreciate some guidance. I will be milling PCB's, some wood, and plastics. I would like to be able to do SOME Aluminum (I realize this requires very small passes, but that's fine) if at all possible. I would like travels of approx. ~12" x ~10" x ~4". If there are any inexpensive kits that you would recommend, please let me know! If you think that I should still try to build my own machine, let me know as well.

Thanks,


- Jesse

[DIYaholic]

I too, discovered that my original plan to build a "Cheap & Accurate" machine was actually going to cost more in the long run (and not be as accurate). Like you, I won't be building anything until at least summertime. So I'm utilizing the cold New England winter to research, design and source a machine of my own design (OK, I'll actually be stealing everyone else's ideas).
I would think that buying a kit would be more expensive than building "your own design". Now that being said, "your own design" can be one of many designs already built and documented here on the Zone. I would put your time to good use by researching the build threads here on the zone, find a design that fits YOUR needs. You may need to slightly modify that design to work within your budget and sourceable materials (ie. "on sale"). I would think putting your new found knowledge to use, will benefit you both financially and intelluctually.
Well that's my $0.02. Good luck, in whatever direction you go.

Randy,

[Pplug]

You could start looking around e-bay for pseudo NC machines that you could get cheap. For instance, my first CNC was a converted omis 3 optical cmm with a linear slide for the z axis. It even came with a 500 lb granite base and an enclosed cart all for the price of $500! Look around and you might be able to find a deal too!

[FandZ]

I think the modular cnc option is a good one. It's a hard deal to pass up on. I'd go for the one around 375 to get the extra room though. I often recommend someone to buy a cheap cnc machine if they aren't experienced in wood or metal working like I was and still am to a good degree.

There is nothing wrong with DIY. You just get out what you put in. The mechanical components of my first machine was under 200. It's only draw backs were a bad Z axis design and unprotected rails. It could do wood and plastics with no problem. I accidentally plowed through some aluminum (the machine itself) with it before. But I never tried to actually mill aluminum with it. Accuracy was in the .005 range or better. .02mm is what my caliper read but I didn't believe it. It's getting nice and rusty on my back porch now.

If you do go DIY, use 80/20. You will not regret it. Even if it's the lite versions.

[Jesse B]

Thanks for your input Randy. It seems that we've bee following a similar path in our, say, ordeal

Originally Posted by Pplug You could start looking around e-bay for pseudo NC machines that you could get cheap. For instance, my first CNC was a converted omis 3 optical cmm with a linear slide for the z axis. It even came with a 500 lb granite base and an enclosed cart all for the price of $500! Look around and you might be able to find a deal too!

I've been keeping my eyes peeled for anything that grabs my attention on eBay. Depending on how this summer goes will determine my budget however, so I'm trying not to get too excited

Originally Posted by FandZ I think the modular cnc option is a good one. It's a hard deal to pass up on. I'd go for the one around 375 to get the extra room though. I often recommend someone to buy a cheap cnc machine if they aren't experienced in wood or metal working like I was and still am to a good degree.

I guess as to which version I go with will just depend on what I really want to do with it. I'd like to say that I will have dozens of uses for this thing, but realistically there's only a few things that I will need it for. That being said, I'll have to make a list, as I'm sure there are more things that will aid in my decision.

Originally Posted by FandZ There is nothing wrong with DIY. You just get out what you put in. The mechanical components of my first machine was under 200. It's only draw backs were a bad Z axis design and unprotected rails. It could do wood and plastics with no problem. I accidentally plowed through some aluminum (the machine itself) with it before. But I never tried to actually mill aluminum with it. Accuracy was in the .005 range or better. .02mm is what my caliper read but I didn't believe it. It's getting nice and rusty on my back porch now. If you do go DIY, use 80/20. You will not regret it. Even if it's the lite versions.

DIY seems like it could be a fun project. I'm just worried about a couple things. First off, sourcing materials; shipping to Canada is EXTREMELY expensive for absolutely no reason, so I have to shop around a lot. 80/20 seems to be fairly affordable and have acceptable shipping rates however, from the few ebay stores I've checked out. Another issue I'm worried about is my utter lack of tools for this type of thing. I've got most basic hand tools, but there are definitely some more expensive tools that would make my life easier. Who knows, maybe the school I'm going to in September will have a nice open shop for me to use


Thanks for all the input so far. More would still be appreciated, as I like having as many opinions as possible!

Thanks,


- Jesse

[stangtjk]

If you go the diy route on a tight budget keep a sharp eye on ebay for anything your can use. I got this linear actuator a couple weeks ago for $21.50+shipping that I'm going to use for my z-axis. Its going to be the nicest part of my machine and one of the cheapest.

[Jesse B]

Originally Posted by stangtjk If you go the diy route on a tight budget keep a sharp eye on ebay for anything your can use. I got this linear actuator a couple weeks ago for $21.50+shipping that I'm going to use for my z-axis. Its going to be the nicest part of my machine and one of the cheapest.

Wow, that's a great deal! I'll be sure to lurk Evilbay as much as I can once the time to build approaches!

I've refined one of my previous designs, and then modified it to be a bit smaller, just to look at my DIY options. The original design of mine has approx. 14" X Travel, 8" Y Travel, and 4" Z Travel. The smaller version (but still the same general design) has about 8" X Travel, 5" Y Travel, and 4" Z Travel. I have another idea for a smaller version that has increased Y travel as well. However, these are the rough dimensions I'm looking at here.

ModularCNC: 6"x4"x4"
My Design 1: 14"x8"x4"
My Design 2: 8"x5"x4"

I really like the ModularCNC kit, but I'm just starting to feel that it's a bit small, and will limit what I'm able to do. My designs are plenty big for what I plan on doing with them. I just need to decide how big is big enough, with cost in mind. I might post some renderings of my designs once I play with them a bit more

On an entirely unrelated note, I have a couple questions to do with the one portion of this rig that I've managed not to even think about yet: the spindle. I want something that's fairly powerful, but is A) Inexpensive and B) Small enough to fit on my little machines. I'm going to be doing a lot of PCB's, which I understand takes very little spindle power. However, I'd like to be able to route wood and plastic, as well as engrave aluminum, so it has to have some oomph to it. I have seen something that people use, but I have no idea what they're called. In the Instructables article I found it in (link HERE if anyone's interested, step 13 has the picture), it's referred to as a "Foredom Handpiece". Beats me what it really is. What are these, and are they suitable for this application?

Thanks,


- Jesse

[stangtjk]

I just did a quick google search for Foredom Handpiece, looks like its some kind of jewelers die grinder meant to be used with a flex shaft. For what you're talking about doing I'd think that a dremel or similar tool would work just fine.

[DIYaholic]

I would take a look at the specifications/pricing of small trim routers. I haven't looked into them, but you may find one small enough for your machine with the "Umph Factor" for wood and plastic.
Just a thought.

[Pplug]

I bet you could get some pretty good deals at local garage sales this summer.

[FandZ]

I think any of trim routers will do what you want. I'd avoid a dremel or foredom as I think you will be limited to using 1/4 bits or smaller. You want something more on the lines of a trim router that can take a wider range of collets.


If you want cheap but good get the HF trim router. http://www.harborfreight.com/cpi/cta...emnumber=44914

If you good get the colt

Amazon.com: Bosch PR20EVSK Colt Palm Grip 5.7 Amp 1-Horsepower Fixed Base Variable Speed Router with Edge Guide: Home Improvement

Amazon.com: Bosch PR20EVSK Colt Palm Grip 5.7 Amp 1-Horsepower Fixed Base Variable Speed Router with Edge Guide: Home Improvement

If you want better get a T4 http://www.sears.com/shc/s/p_10153_1...0070921x00003a

[Jesse B]

Originally Posted by DIYaholic I would take a look at the specifications/pricing of small trim routers. I haven't looked into them, but you may find one small enough for your machine with the "Umph Factor" for wood and plastic. Just a thought.

Alright, I'll have to look into that.

Originally Posted by FandZ I think any of trim routers will do what you want. I'd avoid a dremel or foredom as I think you will be limited to using 1/4 bits or smaller. You want something more on the lines of a trim router that can take a wider range of collets. If you want cheap but good get the HF trim router. http://www.harborfreight.com/cpi/cta...emnumber=44914 If you good get the colt Amazon.com: Bosch PR20EVSK Colt Palm Grip 5.7 Amp 1-Horsepower Fixed Base Variable Speed Router with Edge Guide: Home Improvement If you want better get a T4 http://www.sears.com/shc/s/p_10153_1...0070921x00003a

Thanks for the suggestions! I'll definitely consider those options.


- Jesse