LR4 build, Y axis shorter?

[Hobbydave]

I’m planning a 36 x 24 LR4 upgrade from my older Primo. The documentation clear shows to have the y axis longer than the x axis. My table for the cnc is 4ft wide x 3ft deep along a wall and there is equipment on both sides of the table. Id like to make the x axis the 36” leg and the y axis 24”, is this an issue with a smaller build? Thanks in advance for the help

[Tokoloshe (Philipp)]

Hey Dave, I had it the same way, Aza as well. As long as you know it‘s less rigid than the other way round, everything is fine. You can still push the machine fairly hard.

[Hobbydave]

Philip,

Thanks for the response. I found another thread about this and the general consensus is against it. Since you have practical experience with the y being shorter, no issues? Would you build it this way again or find a way to build it as Ryan specified?

[Bartman]

@Hobbydave

…the general consensus is against it.

In general terms, it is correct that having the gantry (X axis) as the shorter axis is preferred. This is because the longer the gantry, the less rigid it becomes (more bending, sagging and flex).

However, this usually is in the context of people wanting to build larger machines, where the gantry is in excess of 48", and the Y axis is significantly less than that. In that scenario, users would give up some (arguably significant) performance by having a longer gantry. Note that they would still have similar performance to a full size machine (4’x8’ cutting area), but it would be less than if they built their smaller machine as recommended.

In your case, you are looking at a cutting area of 36" x 24". While it is true that the machine would be stronger if you made the gantry (X axis) the short axis, your gantry will still be much shorter than a full size build, so you can expect better performance than the larger build.

So for your case, it is fine (IMO) to proceed with the gantry as the longer axis. In many other use cases, maybe not so much.

[jeyeager (Jason Yeager)]

It does make it more difficult to cut the strut plates.

[Bartman]

@jeyeager

more difficult to cut the strut plates.

This is another truth that needs to be considered. It is possible to work around it, but it is much simpler to do if the gantry is the short axis.

[Tokoloshe (Philipp)]

@jeyeager

It does make it more difficult to cut the strut plates.

I have a video for that:

@Hobbydave

Since you have practical experience with the y being shorter, no issues?

Not really, no. You can see my build thread here:

LR4 - Ghostrider B2/RC2

When the LR4 Beta was announced, I was pretty stoked since I had been harrassing Ryan for a while then about any news on the update. The only thing I got out of him was the rail size. While pondering what theme the new one should have I stumbled upon Glow-in-the-dark filament and printed the ghost from Mario, Boo, at the end of May when it hit me: The new one is the Ghostrider. [IMG_20240611_205023] [IMG_20240612_002942] The beta started while I was drinking beer at a Festival, and because @…

Or watch my videos:

HaWiWe

It’s an incredibly versatile machine for the price.

[Hobbydave]

I did see that in the documentation. Fortunately I can cut them on my Primo before dismantling it for the switch to an LR4.

[Hobbydave]

Thanks for the link, I will read through your build and Thanks to everyone for their input.

[Nathan_Doty]

It doesn’t matter which is longer as long as the gantry doesn’t exceed the 48". The design keeps the gantry fairly rigid but it will get flexier the longer it is, while the table rail is not affected. Calling 1 x and 1 y makes for easier discussing but the machine doesn’t care.