Manual machining stuff and rethinking bearing rails.

I have been doing a little manual machining to get ready to make some stuff for my CNC ideas.  I finally figured out how I can use my milling attachment on my little 7X10 lathe.

To make the milling attachment work, I added a milling table which is from an old Incra jig right angle fixture.

To mount it to the milling attachment, I just added a solid block of 1-1/4" x 1-1/4" aluminum to both clamp it into the attachment and also to provide a backing for the extrusion.

Next,  I will also make a vise and then a tooling plate for attaching other things like my rotary table.

In other news, I got a large bag of 8mm hex head cap screws for mounting 608 bearings. Of course I forgot to order some washers but that is life. I will pick a few up at the hardware store while I wait for an order of them to come from online.

I keep rethinking my bearing rail ideas and am considering going to a steel tubing rather than the aluminum angle for the bearings to run on. I just hate the idea of running the hardened steel bearings on something as soft as aluminum. It would be easy to make but I don't want to have to keep adjusting and replacing rails. I could go with a steel angle but it leaves me with the same problems and none of the advantages of using the aluminum rails.

I also got a shipping notification for my grblShield for my Arduino. If you are not familiar with it, it is a 3 axis controller board that attaches to an Arduino microcontroller. I have a parallel port breakout and stepper controller but I really want to try running it from the Arduino instead of the host computer. It is a trade off but I think it really is a better way to go. I can use my parallel breakout on a CNC lathe I have at work to play with and have all the electronics for another system using the arduino and 4 easy stepper drivers.  My ultimate goal is to get to the point of being able to do 4 and 5 axis routing but I am going to build the first machine to use to make further experiments.

Still alive.

Things have been hectic in the real world day job and have not had time to add any real information. Here are the things that I have been thinking about for my machine in the meantime.

Structure:

Ok, I have the metal for my rails, but I am not cutting wood yet until I have a firm plan with all the details. I also need to make a sub-fence for my router table to fit around the bit that I will be using to cut the support rail profiles. Shouldn't take that long but I have not been that panicked to just build without thinking things through. If any of the readers here are that anxious to just "get something made", I really suggest going with one of the proven designs. This one may actually suck. I am fully prepared to accept that outcome. If I was just wanting to get something made myself, I would have just gotten one too. I am designing this to test out my own ideas.

At present, the two design components I am deciding on are the Z-Axis and routing and idlers for my chain. I have a few ideas for the idlers but I need to sit down and test some parts to see how well it works. The main part is to hold the outer race of a 608 bearing. Maybe a press fit, maybe a plate to hold it into a recess. I have to clear off my drill press area to make some test pieces and see what I like best. The Z-Axis will have to fit around the idler so it will have to be the decision on the idler first. I also have to figure out the routing for the chain for the X-Axis as well. I am most concerned about getting it out of the way from swarf or sawdust. I might just have to make the box for the base taller to give me some room.

Controller:

I ordered a different motor driver board for my machine. I have been really thinking about the idea of making mine Arduino controlled. Yes, everyone uses CAM software to move the machine around.with parallel port control with Mach or EMC2. Well, you know what? How do you explain the fact that there are people running CNC stuff quite effectively with USB connection to an embedded controller. RepRap, Makerbot,  and a newer one named Dank that I found through an article on Make Magazine. There are others as well. Planet-CNC has a really nice little USB based PIC controller that  handles the motion control. Also, there is a whole market built up from doing motion control over USB. Just about all printers and many engraving machines use USB control. No, they don't do really sophisticated G-Code with subroutines and such. That's fine. I am not looking at doing a lot of high end G-Code. I am going to use other design software that generates it like Inkscape and SketchUp and run computer generated code.

Enough for tonight. More soon.

Just a heads up on another project.

Mike Calvino has a project over on Kickstarter.com that is a really good example of a well though out gantry design. I see so many bad examples, I want to make sure and point out a good one. Most of the ones I see on this kind of project look like a 15 ton gantry crane. In comparison, this one looks positively elegant.

I wish I had the room for something like this 5 Axis monster.