The X-Carve Minus

After messing around with my new XC 1000mm for a week or so, I got tired of the gantry flexing and various alignment issues. So I’ve started work on the “Minus”, so named because I’ve gone taken my Makerslides to the tablesaw and trimmed them up a bit. Here’s what I’ve done so far.

  1. Trimmed the Y-axis slides 2 mm to eliminate the 2 mm gap between the X and Y axis subframe slides. Hopefully this will help ensure squareness when I connect them up with the gussetted extrusion brackets.

  2. Trimmed the X-axis (gantry) slides to 81 cm. If I did my math right, this should leave me a work area of 61 cm, or just over 24". Hopefully reducing this length will help reduce some of the leverage exerted upon it and flexing.

  3. While I had everything apart, I added a 3/16" aluminum bar stock stiffener between the gantry sides and drilled an bolted it in place.

I’m starting to put it all back together now and will incorporate a few more changes as I go. I want to run the sub-frame slides directly under the Y axes, like @AngusMcleod had shown in one of his posts on stiffening mods. I will connect them together (somehow) so that the Y axes slides can’t deflect anymore. Once the machine is running again, I’m going to try to mill out some new end plates out of 1/4" aluminum which will incorporate a couple more stiffening mods.

I took pictures, but I need to trim and crop them before I can post them. Will keep adding to this entry.


I was surprised when I saw this gap, the whole assembly was so smooth… until this.

Ok, so today I got up with the idea that I’d make a couple t-slot nuts and then go about putting the XC Minus back together. Well, I obviously underestimated the amount of work it would take to make 50 t-slot nuts. Suffice it to say that they’re done, but nothing else is. I did learn along the way that the Diablo Steel Demon saw blades work pretty well on angle iron, but they won’t last very long. Oh and word to the wise, $25 for 50 t-slot nuts from Inventables is cheap, real cheap. In my defense, I wanted them “now”, but I won’t be making any in the future, that’s a promise.

$10… damn! That’s like a knife directly in the kidney. lol Still, I did get to spend 6 hours of quality time in the workshop and was able to get reacquainted with my bench grinder.

Made progress on the reassembly of the XC. Hit a few slow downs related to the rework.

  • M6 bolts used in X-Axis stiffening were too long and interfered with operation of carriage. Solution: Removed washers and replaced regular nuts with nylon locking ones and cut bolt threads flush with nuts.

  • Limit Homing switch bolts in carriage interfere with stiffening bolts. Solution: eliminated the homing switch. I hate the default implementation of these anyhow.

  • Motor wire for right-side Y-Axis stepper motor doesn’t fit through Makerslide anymore. Solution: …actually, this one I don’t have solved yet. Started by trying to route the wire through the back slot that was used for the homing switch stop-bolt, but that wasn’t ideal. Might try running it under the bottom of the gantry next. Suggestions welcome.

Getting closer though.

The Minus is getting closer to being at full functionality. I decided that it would only be appropriate for it
to be responsible for making some of its own stuff, kinda like making your dog carry its own water on a hike. So I co-opted it into making some aluminum Y-Axis supports, these to be exact. Have I mentioned that I’ve never machined aluminum before? Boy, what a learning curve! Making 8 of anything gives you plenty of practice though, and I can make one of these in about 35 minutes now, instead of the 1.5 hours it took me the first time. And I only broke one end mill and made another into a welded aluminum mess along the way.

Once I have these done and installed, it’s time to address the wasteboard for real.

Almost done (I hope, please God do I hope I’m almost done).

  • Got the base bolted to a piece of MDF. Drilled holes through the 2cm slides and ran 30mm M5 bolts through from below and into t-slot nuts.
  • Attached 6 of the new aluminum Y-Axis supports that I milled out of 3/16" stock (3 per side).
  • Trimmed down the Inventables spoilboard so that it fits inside the reduced XC footprint and bolted it down to the frame.

I believe I have a pseudo-torsion box base now. If not, it’s at least stiff and heavy. Pulled one of the power wires out of the Arduino box by accident, so need to fix that now. Also noticed that carriage has a little play in it, so might install the new eccentric spacers I bought along with a locking M5 nut.

I have to say that I’m looking forward to having this thing put together and doing something useful. I’m a big fan of Inventables and this forum, but here is some pointed feedback for you.

  1. The base arrangement as shipped is not good. The slides aren’t cut accurately, which means you can’t lock the base together into something square. Furthermore, the base and wasteboard really need to be put together in such a way that they are attempting to be flat. That means some sort of torsion box setup. You’re clever engineers, figure something out and suggest it to people when they put the machine together. As-is it doesn’t cut the mustard.

  2. I’m thrilled for you that you’ve come up with a one-piece gantry, but the 2-piece one that shipped with mine (and everyone else’s) sucks leaves a great deal to be desired. With 1 meter of leverage, you’re completely reliant on that gantry connection being square and solid. With the slides connected it’s better, but you can still flex the gantry plates. Time to run the Solidworks finite elements analysis some more, I think.

  3. While we’re on the topic of the gantry, a real way of setting it square prior to operation would be greatly appreciated. Maybe some custom stop blocks, or something. But the fact that you don’t even call out the fact that you can easily skew the gantry inadvertently is bad because it means people can get into an additive calibration mess if they’re not careful.

  4. The electronics assemblies and wiring as you ship them are a mess. The image below should not be what people end up with when they’re done. That looks like a bad science project, not a $1000 kit.

    If you don’t want to spend the money on shipping something better, at least document some alternatives with parts lists so that people can put something better together. At a minimum:

A - The stepper motor and homing switch wires should run into some real connectors.
B - The fan wires… do I even need to say anything about those? There are better ways to manage those - there has to be.
C - The power leads for the Arduino should go into a barrel connector, like what’s already on the Uno now designed exactly for that purpose.
D - Consider selling a real enclosure for all of this mess, one that I can bolt everything into, plug the stepper wire connector into on the outside and that I can bolt onto my support table somehow. I mean seriously, what was the intent here? It’s just awful.

I’m totally willing to give you a pass on the v-wheels and eccentric nuts. They’re a good idea that just doesn’t work out all that well in practice. Thankfully it’s fairly easy to make them work better without a bunch of re-engineering.

As I’ve mentioned before, the quality of the Makerslides, motors, steel bits and odd pieces is all great. I’m just kind of annoyed that A) it requires so much tomfoolery after assembly to make it work properly and B) that I have to assemble it completely in order to ascertain all of the shortcomings.

Sorry for the rant, but I’ve just spent another full day screwing around with tuning and upgrading, which is NOT how I wanted to spend it. And before someone writes to me an blows smoke creatively up my posterior about hobbyist blah blah blah, take heed. Bad design is bad design. I’m not saying the X-Carve is a bad design overall, but I am saying there are flawed aspects to the design. The same topics keep coming up over and over on this forum from new users. That by itself should be a clear indication that some revisions are needed.

Pictures forthcoming when I complete the next round of steps in my ongoing fustercluck.