So I have 1500mm by 1500mm CNC that runs on dual v wheels on openrail. I'm trying to convert it to linear rails but I don't think my ideas are going to work. I've already got it took apart and I thought I could use most of my old plates but I don't think they'll be tall enough. Will just 1 rail on each Y axis be enough? If I bolt the plates for the X axis to the blocks will it cause twist at the bottom since there will not be any support? I had planned on using .25 inch aluminum for those. Next question is how tall should the x axis gantry be to run a 300mm z axis? Again, thought I had it figured out. Not sure now.
This build has the files for blocks that will make it so you can use existing plates. 1510 Workbee Modified. Obviously, the Y axis block does not apply if you are using a LEAD 1515 to start. You never mentioned what you had. However, the LEAD machines use the same plates for all axis so pick whichever you like best between the X and Z axis. I did something similar to those blocks. Using my existing CNC, I cut all the plates I needed before disassembly. I chose 3/16" thick aluminum angle for my mounts. I just used the step files of the OpenBuilds plates to model my plates so all the holes lined up. They all attach to standard OpenBuilds cbeam linear actuator plates. Here are a couple pictures. The red arrows show where they attach to the black plate from the High Z axis kit for the Y axis. Below, the plate in the middle has a spacer for the two anti-backlash nuts I milled from white delrin since I have 1/2 - 10 five start screws on the Y axis which were salvaged from my older machine (seen in the background of the first picture before full disassembly). I could no longer find any 1/2 - 10 five start ab nuts for sale. I used 2 linear rails on my Y axis, but I do not feel it was necessary because mine is resting vertically on it rather than hanging off the side of the C beam. If you want to do it the easy way, read through the build I linked above and have a machine shop cut your blocks. They were designed for the Lead plates. Jacob uploaded the files for them in the file section. If that is cost prohibitive, reassemble your old machine and make your own.
It's not an openbuilds machine. It's called Routakit. The company is no longer in business. It was basically a larger, somewhat beefier version of the original x-carve/shapeoko before they split.
Consider selling it as-is before its taken to pieces, and putting that toward a new Machine Kits - Page 1 - OpenBuilds Part Store Kits = pre-engineered, proven to work, comes with support, a whole lots less "stress" which from your thread title I am sure you'd like less of, and OpenBuilds reliability built in A lot less work (and guesswork) and likely cheaper (if you include schoolfees, mistakes, repurchases, etc) than a rework
So I'm still "somewhat" determined to convert this machine to linear rails and ball screws. Is there an easier way to determine what height the BK/BF blocks need to be to drive the axis? I've got the rails and blocks mounted, I've put the plate on there that I want to use and I've measured and prototyped a hundred times it seems. It's always just too tall or just too short and I'm using calipers.
The easiest and most accurate way is to model it in a CAD program using the pre-made .step models of parts. That way you will know all your holes will line up properly and everything will fit as it should Many companies provide those files. McMaster-Carr has various CAD models for most things the sell. Once I needed a PVC endcap for a project that was not plumbing related and therefore it did not have to meet specs. I went on McMaster-Carr and downloaded the .step file for the 3/4 inch endcap and 3D printed it because it was quicker than going to the hardware store...and I am lazy. OpenBuilds has all their parts available as well. If I had not done the CAD design work for this most recent CNC router build, it would have been very difficult to get an accurate measurement of the space between the gantry plate and the edge of my 3/4" thick anti-backlash nuts. In the CAD software, I just hid the front Y plate so I could see all the way down the Y axis and drew a line that measured 12.299mm (circled red areas). CAD made it easy to see I needed a 12.299mm thick spacer.
