DIY CNC vs. handmade (FLA 100)

[Alvarado1357]

Greets all,

I've been lurking about for a few days; incredible resource, great group of knowledgeable people in this community. I'm a guitarist and occasional luthier looking to realize a few guitar designs that have been forming in my mind over the past 20 years.

It appears that there are several DIY routers that could easily handle most aspects of my designs; I'm particularly impressed by the FLA-100, given the limited tooling needed to assemble it. For my purposes, it appears I'll need a working area of 14"x32"x4", and would build the machine to meet that spec.

There is one aspect of my designs that may be beyond the capability of this type of machine, however, and I'm posting in hopes of getting some feedback with anyone who is using a DIY machine to create press-fit wood joints. An example of what I have in mind can be found near the end of this video:

http://www.youtube.com/watch?v=4qzCY492lyA

If an 8020 style machine like the FLA-100 can do THAT to mahogany, I'd be pretty stoked. Perhaps there are alternative 8020 designs to the FLA-100 that would be more suitable? Thanks for sharing your expertise!

[analogman]

Is there a forum for that kit? I did a google search on FLA-100, and not too many hits came back. Personally I would pick a kit that had a good support forum. There are a few here, (Joes CNC, Hybrid and JRGO) comes to mind. Check out the support forum on this site.

Mechmate is another well supported one, but it is a big machine.

Check out also solsylvia plans.

[Alvarado1357]

Good point. The more users of a given machine, the more expertise available, something I'll likely need to take advantage of during my build.

The machine I was referring to in my original post as an FLA 100 is made by Fine Line Automation, and their full designation is FLA 100-00. A long thread on the Open Source CNC Machine Designs forum brought it to my attention: 2'x3' Free Router Plans - All Aluminum and Steel, Completely Bolt together

[BobF]

Alvarado1357,
I watched your video and saw your neck attachment. I guess what you are asking is can you cut a nice tight fit like that. No problem.
I use a tight fit pocket to create holding fixtures for all sorts of stuff. I made one to create a corner finder and zero setting attachment. I cut a pocket in a small block of hardwood to fit a 2" square of acrylic. I screwed the hardwood to the bed of the cnc, and inserted my block. This holds it while I cut a circular pocket in one side to mount a piece of copper pipe. Then I flipped it over and cut the corner depression in 1/4 of the block. The corner lines up perfectly with the center of the pipe. I guess I need a picture of this to make sense of it all.
The point of all this is that cutting fitting joints like that are very doable. My machine is a joes2006.
I also built a similar fixture for cutting pearl.

[Alvarado1357]

Bob, your post makes perfect sense to me, that's exactly what I wanted to know. Thank you very much.

[BobF]

Glad it helped, and your welcome.

[ahren]

Alvarado,

This is Ahren of CNC Router Parts LLC -- Nate Lowrie (of Fine Line Automation) and I created the plans for the FLA-100. We don't have a support forum on this site, as the cnczone site owner isn't willing to create one for it yet. Anyone here who wants to encourage him to do so, feel free While this particular machine is new, there are over a dozen machines that I know of currently using my parts with great success, including a couple of guitar makers.

That being said, you can get support on this machine from either myself or Nate any time via email. Additionally, I'll add that the machine can do what you want. Check out the videos here that show machining operations in solid fir:

http://www.peakeff.com/beta/PostDetail.aspx?PostID=11

Feel free to email me through the website or PM me with any specific questions -- Nate and I would love to see your machine be one of ours!

Best regards,

Ahren
www.cncrouterparts.com

[Alvarado1357]

Hey Ahren,

I have both your website and FLA on my faves; great parts and machine. Sadly, the FLA-100 has alot more y axis than i need/want, and a bit less x axis than I need, so I've already given up on any hope of buying the kit, which I wouldn't be able to afford anytime soon in any case.

What I'm envisioning at this point for my purposes would be a dual screw x axis, using a gantry that sits atop the x rails (no wraparound); smaller footprint, less torsion on the gantry, etc. I think Heiz makes machines using this concept. As much as I'd love to have linear rails and ballscrews on my machine, it's pretty clear that I can get more than enough accuracy from the linear motion used in the FLA machine, so I probably will be sourcing my bearings from you, if nothing else.

I read somewhere in one of the threads regarding the FLA that a dual screw design was in the works, which I would love to see, along with some parts from you; motor mounts immediately come to mind. I'll email both of you guys presently.

And yes, I think a forum dedicated to DIY 8020 type machines would be a welcome addition to the CNCZone forums. I know I'd certainly welcome it.

[ahren]

Alvarado,

Why do you want dual screws for a machine that's only 14" wide? There's very little chance of racking in this configuration, and with a shorter gantry, torsion is also limited. I'm sure Nate would sell you components cut for a smaller machine. Additionally, the travel in the long axis should be close to 36", so that should meet your 32" spec.

As for dual drive, it's on our list of things to do, but for now we're trying to stay focused on a design for a rack and pinion based machine once my system is available.

If you're set on a dual drive machine, the current motor mounts will work with vertically oriented rails. You'll have to design it yourself, but the good thing about 8020 is how flexible it is. I'll be happy to supply parts and support whichever way you go.

Ahren
www.cncrouterparts.com

[Alvarado1357]

I won't even pretend to have a quantitative answer as to why I'm so hypnotized by the dual screw design, and I've read the arguments against it on the forums, so I consider myself forewarned. I certainly won't be saving any money going that way, either, given the need for an extra screw assembly, etc.

Still, that's the design that satisfies whatever intuitive sensibility I've developed over the years regarding jigs and tooling generally, and I'll most likely be following it. However, the idea of simply making Nate's design with a smaller y axis is tempting, so I'll let that thought settle in a bit. 32 inches should be just enough to mill the guitar neck design I'm going to use.

Plenty of time to make up my mind; issues like footprint, gantry height, racking, torsion, backlash, table flex, etc. may ultimately be less important than the total cost of tooling up in terms of time and money. Nate's design seems more than capable of the accuracy needed for what I'm going to do.

[solodex2151]

This is Nate from Fine Line Automation. The advantage of the dual screws is you can go with a completely overhead gantry, though at the length you want I would consider moving to a Rack and pinion setup. I really like an overhead gantry design for dual drive. It moves all the linear motion and powertrain components up out of the way of debris and resists racking better that a wrap-around gantry. Note that by the time you are ready to build your machine I should have 4' rails available.

Edit: I need to clarify this. I thought you were looking for a 4' travel on the X-Axis. I didn't realize it was only 32" or so you were after. In that case, a leadscrew setup is preferred and more cost effective.

Regards,

Nate

[Alvarado1357]

Hey Nate,

Really nice to see this level of involvement from both you and Ahren; not too many worries about product support on my end, after hearing from both of you personally. Very impressive. Not to mention how amazing these forums are; just an incredible community of people and expertise.

Your remarks echo my thoughts regarding overhead gantries. Power is also an issue; mahogany guitar bodies are 2" thick, neck blanks are 3.5". The forces trying to pull a wraparound gantry out of square while doing that kind of work give me the willies.

I don't see any reason why a well built 8020 cnc wouldn't be able to perform the functions of a tablesaw, jointer, and planer for my purposes; I'll just have my wood supplier provide me with rough cut stock. Perhaps the durability of the machine chassis is an issue, over time? Still wrapping my head around some of this; the shop footprint keeps shrinking, nearly to the point of being a long workbench, as I ponder and research what can be done with cnc. As I'm writing, I'm wondering if I really need that drill press after all...

As for the upcoming rack and pinion setup, I'm hoping it'll be out before I get to the build stage, especially if it'll allow me to get my yz assembly from you. My machine will definitely be made of 8020, using the gecko 540 controller, and I'm pretty sure I'll be going with the kress spindle.