Ok so I was in Darren's thread about his CNC router and mentioned that I'm in the midst of building one myself. I'm on day 21 and have a rolling gantry going at this point. I'm waiting for my lead screws to come in before I can continue at this point.
So I'm not 100% sure how to structure this post - so I'm just gonna do one post for each day of progress so you all can kinda follow along. I have been designing it for the last year and started on the thing about 3 months ago. Just getting nights and weekends and a few gaps in the progress just because life gets in the way, yanno.
So here are some overview shots of the design. It was inspired by a Joe's 2006 design using a torsion box for the main table. I picked up some really cool linear bearings that I decided to use and made some pretty significant changes to Joe's original design. It's also mostly out of aluminum from that point on. This is because I have a really great place in town that I can buy aluminum stock by the pound and it's pretty cheap - for $3/lb I'm pretty happy to get just about all the plate, angle and shapes I want. They recently had a load of salvage channel that I snatched up and decided to design my gantry around. That's why all this design stuff for a year...
Anywho ... pics!
The green rectangle is the total machinable area. I designed it with a 3" overhang past the end of the machine so I can fasten work vertically to it and machine the ends. Fancy dovetails, mortises, etc. I don't know how useful I'll find it, but it wasn't terribly tough to do and I had the extra rail length anyway.
In case any of you are interested in more design stuff, I took a few videos from sketchup and posted them on youtube:
They're kinda random without context, but it does show some more detail of certain parts of the machine. Not everything in the videos made it to the final design but they're not too far off.
OK! Next up - the Day 1 Fun
Edit - it dawned on me that I didn't give much in the way of specifics for the machine. The total machining area ON the bed will be about 26" wide by about 56" long. There's a 3" overhang added to that end. The Z axis will have 7-1/2" of travel, with a full 6" of clearance under the gantry's lowest point. The lead screws I ordered are as follows:
Z Axis - 3/4"-6tpi Acme Screws (6 turns per inch)
X and Y Axis - 3/4"-.500" lead 4-start Acme Screws (2 turns per inch)
I haven't chosen my steppers yet because I want to get things together first to see how much torque I'm gonna need for the whole mess. At the moment, the Keling kits are looking promising.
My plan is to also use the machine to build a rotary 4th axis. Sorta like a mini lathe controlled by a stepper.
I'm building this machine to be as rigid as I can muster without breaking the bank. My hope is that I'll be able to machine brass and aluminum with it as well as wood. I plan to use it to make patterns, jigs and rough out guitar parts when it's done. I also figure it can earn a living while i'm not using it as well once I get to learning it all.