With the length being 1000mm do you run into any flex or undesirable movement? The project size that you built is about the same as what I plan on building. However I am going to make the sides a little more beefy by bolting them to 4" aluminum angle 1/4" thick. I am not sure if I am going to cut the angle into 4"-6" pieces or just leave it the length of each side. The aluminum angle isn't terribly expensive considering what the extruded aluminum costs. Here is a link to it on Amazon if anyone else would like to use it to anchor their CNC project... http://bit.ly/AluminumAngle
I decided to anchor my sides to the table due to their 1500 mm length, but I am using 20x60x1500mm ($23) because it is cheaper than any angle I have found. It too could be cut into shorter pieces and spaced along the length. I chose this because with the 3D printed joiners, I new it would be lined up perfectly (or as near as I could get it). With the printed joiners holding it I will drill and bolt them, too.
Do you mean you are just taking more of the extruded aluminum and bolting it down? Does that still prevent lateral movement? I was thinking of going with the angle aluminum because once the 4" flat is bolted to the base/table it will eliminate the lateral movement. Do you have a picture of how you fixed yours?
I am in the process of attaching extrusion on the inside edge of the Y axis 20x80x1500 mm beams. This will also be fastened to the actual torsion box tabletop I built for the machine. I did this to provide support for the long beams vertically and by fastening it to the table it should help eliminate lateral movement. I can see where the angle could be easier because you can put holes where you want. something like this quick sketch with bolts securing the two vslots.
I see,... but with the narrow base and tall sides aren't you susceptible to lateral movement? Shortly after joining the site I ran across a fellow who used the angle for his project. Which of course gave me the idea, so I give him credit whatever his name is. I have forgotten it, but here is a pic of his work I saved. He used angle that had one shorter side, but there is now zero movement.
I love the charging Ox. TheScreaming Ox is what I used to base my design on, but the lack of cbeam at the time led me to make changes. I had thought about mounting my sides like the above photo, but those angled brackets are ridiculously expensive (IMO). I have not been able to find the ones with the slot in them like in the picture. He said he machined them that way himself. The closest was these http://www.amazon.com/Faztek-Series-Anodize-Aluminum-6063-T6/dp/B008MQ9SNE at $20.62 per piece. They are cheaper on Faztek's site, but since they don't indicate shipping price until you have made an account and completed checking out, I figured it would be ridiculously high. That has been my experience with websites like that. A piece of 2 foot 6x6" angle, like in the parts list of the Charging Ox is $63 (+shipping). The 4" aluminum in your link would come up even shorter on the sides of my cnc. However, that is the fault of my design. You could do yours at any height you want as long as there is clearance for the wheels. I needed the clearance because I may add a fourth axis later for turning legs. I had also considered steel angle since it is significantly cheaper, but hand drilling the holes accurately is a pain and steel makes it even more painful. The reason I chose the v-slot, is that it is readily available and the slots line up precisely (particularly when using these V-Slot connector | OpenBuilds) so I don't have to worry about how well I drilled my holes. The reason I originally was adding the additional support on mine was because I feared sagging over the 1500 mm length. But it should also significantly reduce the potential for lateral movement. I guess I will find out. I can always modify it later, which will be easier since I will have a cnc.
You could buy one of these... 3" x 4" Leg Lengths, 0.375" Wall Thickness, 48" Length- $49.47 including shipping It's more than long enough to cut enough brackets. Then to drill the holes accurately if you do not have a press, just buy one premade bracket and use it as a template and mark-up the new brackets... Then drill away. Here is one that might work as a template. 18 Hole Corner Bracket $7.10
That is a nice bracket. I just don't understand why the shipping costs more than the product. I buy all my aluminum from a local supplier. It is much cheaper than anywhere I have found metals online. That being said, that angle you posted at $49 is fairly reasonable since shipping is included.
For sure if you live in an area with a metal dealer. I live in the Atlanta Metro area and we have Metal Supermarkets here which isn't too bad. But to be honest I have a really bad back and sometimes it is just as easy to order it on-line and have it delivered than to drive 30-40 miles down to Atlanta to buy it. Yeah shipping costs can be a turn off... I am Amazon Prime member so I take advantage of it every chance I get. UPS, FedEx etc... raised shipping costs because of gas prices and when gas prices dropped, they never dropped shipping costs... Go figure. I bought that corner bracket tonight so I would have a template. I would imagine that it can be used in several different ways. I have a set of transfer punches so the bracket will work nicely with my mill, drill press, or hand drill. m If you don't have a set, I highly recommend getting a set of transfer punches because they are not only duplicated, they are also centered too. Grizzly has them on Amazon Prime for $24.94
I'm looking where to get the left and right Gantry plates ? I don't see them listed on Openbuilds, are they custom? I see them in a few other builds so possibly not, Thanks!
On the first page of the Ox build there is a list of people that may be able to supply them. OpenBuilds OX CNC Machine | OpenBuilds If that bracket were metric, it would work for me. However the holes start at 1/2" from the edge and are spaced 1" apart so they won't line up with my v-slots. This would be a better fit for me if I went this route. 40-4304
OH !!! You have the metric stuff. Okay well 80/20 has a 12 hole in metric too. I'd go 12 hole so you can make some really tough brackets easier, but that is just me ;-) And you know I may have made a big mistake myself. Are they selling metric stuff here on open builds? If so I am screwed LOL. I guess I should have thought of that but it was late at night and I had a couple other things going on at the same time. Crap !
Yes we did, I apologize... Can you move some of our discussion into a thread for us? Or if I start a new thread can you move it over?
I received the 80/20 bracket in the mail yesterday. eh... it's a piece of angle cut and drilled. Nothing special they can be made easily mill/drill press or not. Definitely not worth buying these for anything other than using one as a template to get started. If you used then in your project you'd go broke @ $7.95 + $8.30 shipping . Of course they would probably combine some of the shipping, at least I hope so. I took a look at one of the OX BOM's on this site and it is kind of jacked up. Does anyone know of one that is tried, proven, edited, and known to be correct?
This is what I did for the 500x750mm OX build to strengthen the base/side rails. I didn't like the arrangement with the 20x80 front and rear cross rails and the single 20x80 center support. I replaced the front, rear, and center supports with 20x40's and then I added 1 more 20x40 rail under the base parallel to the inside of the 20x80 rails on each side, for a total of 3. Make sure to mount them so they don't interfere with the wheels. These are attached to the front and back cross rails with double corner connectors on each side, at each end. Then, I added 4 cast corner brackets on each side on top of the spoil board at the edges to connect the side 20x80s to the 20x40's under the bed, bolted all the way through the spoil board into t-nuts on top of the 20x40. This virtually eliminates any possibility of flex in the side rails, and strengthens the bed immensely. If you have a longer bed, just add more cast corner brackets. My 750x1000 OX design has 4 bed supports instead of 3, and 5 corner brackets on each side. Oh, and sand off those dang little tits on the back of the cast corner brackets. They don't really do anything and interfere with making the brackets sit flat. I use a belt sander to make short work of removing them. I also bolted the center support and the front and rear support rails through the spoil board into t-nuts on the 20x40's under the bed as well. This makes the whole bed a very solid structure. It is a bit of a pain to get the t-nuts lined up, however. I hot glued a small 6mm diam rare earth magnet on the end of a long 1/8" dowel to fit into the v-slot and push/pull the t-nuts into position. You can easily drop a second spoil board on top of the existing one, just 40mm narrower. The 5-hole brackets front and rear hold it in position. This is easy to replace, and you can flip it once before it needs replacement. 1/2" MDF should be plenty for the secondary spoil board. Drill through it for the hold-down holes.
