I would think the aluminium would be just as good if not better for this mod. If you think about it, the spacer isn’t really adding a ton of strength in this situation, it the act of making the two extrusion act as one piece that adds the strength.
If you were to use steel, your weak point is now your extrusions, and also now with the added weight your putting a lot of unnecessary added stress on your Y-gantry steppers.
Personally I think the steel bar is over-kill, but that’s just my opinion.
Steel has a much higher resistance to twisting than aluminum. Even though the makerslide is now the “weak point”, it is not able to twist as much as when using an aluminum insert; the steel isn’t going anywhere when the makerslide pushes on it. The weakness in the makerslide is then an issue of linear deformation (squishing) instead of rotation, which is very unlikely to have happen on the X-Carve.
You are correct in that adding something to fill the gap is similar to having one solid extrusion, but the filler material (steel, aluminum, etc.) is important; adding foam isn’t going to do much, but as you increase the rigidity of the filler material from aluminum to steel the results are improved. Also, there is definitely added stress on the y-axis stepper motors, but they are capable of handling it in most cases.
Fair enough, the steel still seems over kill for what these machines will be doing. The added rigidity of an aluminium spacer matched with its light weight would surely have more than enough added benefit. Heavy-Duty doesn’t always mean better.
I agree that for anything besides milling aluminum, an aluminum spacer (or even something lighter) would be perfectly fine. I think the goal for some people using the steel for stiffening is to be able to mill aluminum. Perhaps more people are adding the steel bar without realizing it may be more than they need for what they carve. Good point.
That would be crazy! Way too much for milling plastics, woods and soft metals, but hey to each their own.
Fair points! Like you said,
Which the more I look at modifications and the really cool stuff you can do, the more I want to start designing my own custom machine!
I remember buying a printrbot to get into 3D printer. It was really nice to build the printer and see how everything works and why certain components are needed, and which need to be of better quality. I bought the X-Carve with the same mindset. I wanted something I could put together to understand how CNC mills work and why the designs are a particular way. It’s a great learning experience and I’ve enjoyed it a lot so far. One day I’ll be happy to have this experience when buying or designing a new CNC.
I’m using a 1 1/2" aluminum tee to address the issues of weight and twisting of the X axis. I am using the same bolt through procedure as with the steel bar, and then I plan to tap a few holes under the gantry and also fasten the tee up into the makerslide with machine screws. So it will be tied in two directions without the extra weight of steel. I don’t see how it will twist or sag at all. I don’t have my X-Carve yet, but will share my results after assembly.
I have the steel mod and I still would like more rigidity. Part of the problem is the distance of the mass from the center point of the x axis. If someone created the 40 x 40 thick-walled steel box section solution, I would buy it. (provided it wasn’t ridiculously priced and the creator wasn’t all “…I don’t share my designs, yada yada.” It would have to be open source, the creator must not be a total jerk and then, I would absolutely buy it. Just like I bought into x-carve to begin with.
If when my router is off, I drive my bit into my wasteboard, I see deflection. I would rather see bolts shearing on either end of the x-axis than deflection. Someone who did the mod (can’t remember who) was seeing deflection when the bristles of their DUST SHOE met the wasteboard.
So, I will continue to pursue to rigidity mods. But right now I gotta cut stuff.
I saw a supplier with a “non rounded” stainless steel tee. Meaning it has perfect 90° inside angles. It was quite a bit more costly.
Maybe there is only so much we will be able to do with stiffening the stock configuration.
