View Full Version : BUILD LOG: Strange X axis design

08-01-2017, 04:53 PM
Hi There,

I am mainly a lurker here. I want to attempt my build sometime this year, but I have to focus on my business first! Anyway, if this is the wrong sub-forum, can an admin please move it to the right spot? Thanks.

With that said, I want to ask some opinions from here. I saw this X axis design today on Instructables, and found it interesting. For a large bed CNC machine, I can foresee a big cost in the sides. But other that that..., what am I missing? Thanks


08-01-2017, 06:02 PM
Sorry, I meant to say Y axis (as per the guy's build)

Clive S
08-01-2017, 06:43 PM
Welcome to the forum. It is impossible to answer questions like that if you don't state what your goals are ie what do you want to cut, what cutting area do you require and what sort of accuracy do you want to achieve. etc.

There are machines out there driven by belts and they will work BUT not like you have shown you certainly won't get any accuracy with that type of bearing.

08-01-2017, 07:10 PM
Hi Clive,

Thanks for your reply and thanks for the welcome. Here (http://www.instructables.com/id/Build-a-CNC-Router/)is the link to the Instructable. I want to build my CNC Router to do wood, but I also want to have it to be able to fit a door. So *my* goal dimensions would be at lease 1meter by 2.5meters (excluding what is needed for rails/gantry etc).

So yes, to have two side panels 3meters (give or take) long, plus so structural support (ribs?) on the sides to make it sturdy would be a costly exercise I think.

Thanks again.

Boyan Silyavski
09-01-2017, 03:25 PM
There are many builds from sheet material on the web, but almost nobody on this forum does that. |If you find the ribs expensive, then i dont know what you will think when people start giving you advice about motors, boards and so on. Cheap builds are destined to be imprecise and not worth the time and money spend on them.

At the other hand, from steel profile, supported linear rails and some aluminum you can do a nice machine. look around the builds section and see what people are doing here. It could inspire you.

What you have pointed as an example is a dirt cheap desktop cnc which could route soap or chocolate as the hardest material.

09-01-2017, 04:00 PM
The other thing to bear in mind is that the one you've shown looks to be made out of MDF which at the slightest hint of moisture will swell and warp....

Sent from my HUAWEI VNS-L31 using Tapatalk

09-01-2017, 04:20 PM
My first router was built from MDF. It moved with temperature, humidity, phase of the moon, gravitational attraction of anyone standing nearby, or if it felt like it. It could do useful work (I profiled up to 25mm teak with it, slowly, and bed was something like 750x400mm) but it needed continual adjustment (both for bed levelling and general bearing clearances) and could not be relied on for very high accuracy or, towards the end, anything approaching decent surface finish. It was good fun, did some useful work for me, and taught me a lot but Mk2 currently being commissioned is all-welded steel, Hiwin rails and ballscrews for a reason!

Clive S
09-01-2017, 04:29 PM
It moved with temperature, humidity, phase of the moon, gravitational attraction of anyone standing nearby, or if it felt like itI bet it was always accurate on a Friday after a few moonshines

09-01-2017, 07:41 PM
Hi Boyan,

Thanks for your reply. What I meant by expensive for the ribs, is that it looks like a cheap CNC (for a reason I suppose). But to upscale it to the size I plan on, would turn it into a NOT cheap CNC. Also, as mentioned here, MDF is not the best option.

I plan on building mine more sturdy. Steel Square tubing etc. I would want to use it for a while you know? I also have some steppers and a spindle etc which I bought over a year ago! Closer to the time, I shall look for more inspiration here.

So to sum it up.... what would be wrong with this design for the axis like in the photo? (let's assume more sturdy and reliable materials are used)

Thanks (for everyone that gave input here!!! )

Boyan Silyavski
09-01-2017, 09:40 PM
Depends what exactly you would like to achieve. Ideally 80x80x3 steel tubing is best as per my view of things. It will allow to keep things simple and avoid diagonal braces. take a look at my first build in signature, somewhere is the file in Sketchup format. Honestly i doubt a better table with weight to price to strength ratio exists. Then you could further better it if you would like by making the bed on bolts so you could move it up and down. This is not my way of thinking, i prefer a better, longer and stronger Z axis. In the fiirst build there is an excellent example of cheap and properly made Z. As you read you will see that at the beginning i also was not aware of many things.

About the gantry, it could be simple 2x 80x80x3 welded together if the machine is not very very big, or could be like the gantry from my second build. Could be also like many make it from 2x aluminum profiles that form L, which may be easier for you to do at home. And last scenario is sb to cut it from aluminum plate and form a square.

There are many possibilities but what i said are the main successful ones. Also sometimes is not worth reinventing the wheel. Read the builds and stick to the elements you like.