Linear Rails

Now that finals are over I got a chance to do a little more. I made some nice linear rails for one axis of my machine. I CNC'd them from MDF and painted them with epoxy to seal them. They worked reasonably well but ultimately I decided not to use them because they used twice the bearings they needed and were hard to adjust correctly. The hardware also weighed it down a bit. At least I learned a little about working with epoxy.
Now you probably think I'm crazy, and your entitled to your opinion even if you are wrong, but here is where I started over. This time I'm going with a traditional skate bearings and angle stock solution I see all over home made designs. I started by drilling holes for four 8mm bolts to hold my bearings I bought from buildyourcnc.com. The other two holes were drilled from the inside of the angle for mounting to a block. I also used a little blue threadlocker on every nut to prevent the vibrations from loosening them. I'm not sure if that was necessary but it doesn't hurt to be careful.
And here you can see them all finished. It didn't take long to make them and I only needed a drill press, a hack saw, and a few wrenches for the whole thing. Anyone whose worked with aluminum will know how easy it is to scratch so if your fanatical like me, a little steel wool will hide them pretty well and give it a brushed look. Just make sure to rub in circles across the entirety. It's also worth noting the finer the wool is, the finer the finish will be. I used coarse wool to hide the scratches then very fine to get a nice finish. It only took about 7-10 minutes to do all six pieces.

I have a few days before summer classes start so hopefully I can finish at least a few of the axes by tuesday. I have some almost finished blocks for mounting these rails to, then I should be about half way there. So far I like these much better than the first set. I'll have some more pictures soon.

Pictures!!

Here's some pictures of what I have finished...

(Below) A closeup of the front bolt on rail holder. The pipes were threaded so I just screwed them in this end.

A closeup of the rear rail holder. I added some set screws on this end to hold the rails secure. Both the rail holders were carved on the first machine so their almost perfect.Linear slides I made from mdf(also cnc'd) and soaked in epoxy. They turned out pretty well but I might remake these out of oak when I'm done. While I got the first few oak pieces cnc'd I couldn't get these made quite right.
another shot of the assembly.
I have one more cross piece drying at the moment that connects the two slides and holds the nut for the leadscrew. Then the table top just bolts on top with some barrel nuts to hold it all square. I also plan on replacing the X-axis rods with black pipe. They bend way too much with any signifigant cuts which is why I've been having so much trouble making new parts. With any luck I'll be finished in a few weeks.

Chuck's CNC Rebuild: Part 2

So I haven't posted in a Loooooong time. Being busy with school and all I didn't do much lately accept start part two of my rebuild, the bottom half of my new machine. I have to admit, I have more fun working on it than using it. Doesn't that seem backwards?
I built this part mostly out of oak just like before with 1/2in. black pipe for my linear rails and a few temporary parts that will later be properly made when I get it all together. While I liked the adjustment blocks I used for the X-axis I'm trying something new for the Y-axis. Instead of holes or rail supports on the frame I just added some bolt holes and the actual support pieces were made on my machine and bolted on.
Since I'm having rigidity problems I made some of the smaller parts from MDF instead of oak and soaked them in some 2 part epoxy. Now they don't swell with the humidity and don't mushroom when I drop them. I'm going to remake these later after I fix the rigidity problems (reason for my rebuild). I'll have some pictures up hopefully tomorrow.

Fun New Site

I recently found a fun site called Thiniverse.com where you can post and download object files for CNC and Reprap machines. I spied plenty of .DXF, .STL, .SVG, and Eagle Cad files. I saw everything from gears to birdhouses and DIY sunglasses. It's sites like this that make the internet really shine. So join in the fun and share something.

My Experience With EMC

After a long time of playing with EMC and figuring out how it works, I like it way better than TurboCNC. While TurboCNC was a good beginners choice that runs on almost any piece of hardware and easy to learn, EMC is far more configurable, has a more professional look and feel, and lets not forget totally free. In the last few weeks I've been working on settings for customizable controls to run small sections of G-code by the press of a button. I wanted my machine to automatically detect the top of my workpiece using a few simple lines of code. Automatic probe moves are much more fun than a feeler guage and the arrow key. Turns out It wasn't so easy though, as I didn't know much about EMC. My online inquiries attracted the attention of two talented individuals from the linux CNC wiki who were gratious enough to introduce me to classic ladder, a PLC language used for more complicated tasks. If your the adventurous sort you can try out my configuration files, but be careful as they still have a few bugs. USE AT YOUR OWN RISK!! You can check out the details here as well as some other programs. Hopefully I can get a video up soon to clairify exactly what they do.

EMC was definately a steep learning curve but well worth the effort. It is very configurable for custom controls and routing physical input pins to virtually any function in EMC. It doesn't require very expensive hardware either, though I would recommend more than the minimum requirements which I just barely reached with my current setup. Most impressive is its ability to cater to a large range of setups including robotic arms. I always put off building one, but after what I've learned here, I think It'll make my todo list. I would love to hear any questions, comments, or ideas. If there's enough interest I might try expanding the usefullness of this type of function to include some other generally mundane repetative tasks.

Software and Other Stuff

I'm trying EMC2 with my machine. I'm getting tired of the occasional run time error with Turbocnc. Not sure how it's going to work though as my computer is a little underpowered for it. I'll have to let everyone know how it works out later this week. I'm gonna test it out on some small Halloween projects.

WasteOfSpace posted a comment on my previous post about oak that got me a little curious. I smell an experiment brewing. Anyways I've been quiet here for a little while and its about time I start making dust, just in time for the holiday. Oh and be sure to check out these Halloween pictures that switcher was nice enough to make for us.

Chucks CNC Rebuild: Part 1

Well I finally have my machine rebuilt and I'm pretty happy with the results. So far I've replaced the MDF x-axis supports with oak and shortened the z-axis to hopefully help reduce some vibration problems(It was too tall anyways). I've also decided I like lovejoy couplings better than my direct coupling I used before. I'll have to do some research into power transmission and see if it really makes much difference. If anyone already knows then please leave a comment, I'd love to hear some opinions. I also added some aluminum adjustment blocks for the bearing slides. Using a cheap indicator dial I was able to adjust either end of the lead rod within 0.001in which was something I was previously unable to do. I was thrilled, then I remembered the bearing slides flex a little so I measured without changing my setup and you know what it was?.04in difference!! Keep in mind this is with respect to a level board clamped to my table which I'm fairly certain isn't 100% flat. Regardless that will have to go. I plan on changing my bearing slides from 1/2in to 3/4in. I'll do that next along with all new oak parts for the x and z carriages. Despite my disappointment This is a big improvement on the rigidity and adjustability front. I should be able to handle some higher cutting speeds. So whats next? I'm gonna make some stuff. Namely some new parts over the next who knows how long. I have a small laundry list of upgrades for the future:

1. A new QUIETER spindle that can hold 1/4in bits
2. emc2(I use TurboCNC now)
   
3. a vacuum setup instead of just blowing air
4. 3/4in x-axis bearing slides
5. oak z-axis parts(I already designed these in CAMBAM)
6. new, more rigid y-axis
   

After cleaning up the basement starting school and vacation at the cottage I'm finally ready to get back to work. I've finished most of my parts for upgrading to oak parts from MDF. Picture to come when I'm done hopefully by this weekend. Then I can return to switch plates part II.
And to accompany my new upgrade I'll need a new pendant, partially because the first one leaves much to be desired but mostly because I need something a bit more retro. That's why I picked this up at the flee market this weekend.


This new one will be a whole lot better and more complex so probably in the distant future I'll have another tutorial. I'll leave this one for instructables though.

Down Time

Sorry for no posts this weekend but were getting a new heater installed which happens to be right in the middle of my workspace. In the meantime, my copy of Corel Draw arrived, so Im playing with converting some of my grandfathers drawings. Also my router upgrade soon to come, hopefully by this next weekend before classes start.

Switch Plate Part 1

Today I attempted engraving switch plates. Why? They're dirt cheap. You can pick up a few plastic ones for less than a dollar. Turns out I already have some. If your feeling rich and fancy you could also get some wooden ones for a whopping 5-10$ each. I picked up one just to try. In addition to carving way deeper than I intended you'll notice they're off center but still potentially better looking than they were before. I started by drawing a template for each plate so I knew where the holes were. Then I used stylish picture fonts that I converted to polylines and split up. The only issue was I whether or not the template was accurate. As you can see It wasn't, so back to the drawing board for part 2. Not sure It's worth the time though. Part 2 to come as soon as I get it right. I'd love to hear your comments. What do you think ye or nay?