Some pre-build questions

Hello all,

Been lurking around the website for about two weeks now after finding an instructable that credited the original designer and lead me here. This project seems to check all the boxes for what I have been searching for as a hobby. I am a student majoring in Computer Science, and I have an interest in making things but haven’t been able to find a solution to meet any or all of my possible purposes (as in, 3d printers, laser engravers, and the like can be bought as a kit or built, but they usually only serve their primary function; there are mods to make to them, and I was ultimately set on getting a Maker Select Plus as it is a cost effective, proven machine with a strong community, and it had printable mods to attach a laser module).

After finding this build, and its ability to perform 3d printing, laser engraving, and milling or any general purpose CNC work (plotting is the main one here), I have been reading every article, instruction, and browsing the more recent pages of MPCNC forum posts to try and work out a plan before getting started on anything.

In short, after months of research and deciding to potentially get a 3d printer at some point, finding this build and its multipurpose functions seems to be what I was looking for. To top it all off, to read some of the press coverage on the MPCNC and to hear that Ryan is from San Diego (though sadly not anymore as he mentions San Francisco) was pretty cool. Aside from that, it’s a good all around project for experience with electronics, woodworking, hardware, milling, etc. I’m sure all of this has been said before (I think I have seen it here from people doing the same thing).

Here’s my problem: I have been cross-referencing the assembly list with the parts packages in the store (as I am trying to build a 24" square build area machine using the fairest priced parts I can source), and seem to be stuck. In the store’s included parts, you have

1 T8 Leadscrew
1 Brass T8 Nut
1 Aluminum coupler
1 BOLTS 5/16 x 5
whereas in the parts list, there are only three parts listed that require one of each. In parentheses are the corresponding store listed parts.
  • M8 threaded rod (T8 leadscrew)
  • M8x130 bolt (5/16 x 5 bolt)
  • M8x25 coupling nut (aluminum coupler)
I guess the question is whether the aluminum coupler is the coupling nut as above (every part I have seen looks similar to what is in the picture); and is the brass T8 nut just the same brass piece that usually comes on the leadscrew (I think the problem is that the brass nut isn't in the parts list for individual sourcing, but it probably doesn't matter because the leadscrew usually comes with the brass nut)?

I think I just answered those questions.

To check my printing parts, I found on another thread that the currently used parts (which have two sizes in thingiverse) are the 11mm nut lock, and the 5mm (5/16 in) pineapple coupler, not the other size of each (I think 13mm and 8mm, respectively).

Only two other things that have been hard to solve:

Would the 30a power supply (I eventually want to add an extruder and more than likely a heated bed; and as previously mentioned, a laser) need anything other than a 3 prong plug like those used for computers (cutting the end off of the female connector as with the 5a)? Any other wires needed to connect the power supply to the RAMBo (like stranded shielded wire from the hardware store)?

Other than during 3d printing, is there any reason that the table (and work surface) should be level, such as by leveling the four legs/tabletop? I’m still working on how I would design the table if leveling is necessary. Maybe it really is easier to just stick some small wedges underneath the casters if necessary?


I’m sure to have more questions eventually but thank you for your time and patience.



Edit: If it helps, some clarification on my build. 24" square build area, 4" z work area. Probably round up table dimensions to 36" square.



I think if you have a look through the assembly guide you will see all the answers. I will try to run through them here but since this is easily sourced worldwide I have had to make a few parts interchangeable and different sizes.

If you use the T8 leadscrew you do not need the coupling nut. The coupling nut and T8 brass nut are serving the same purpose.

If you use the T8 you also do not need the either lock nut holder and can use two spacers instead. Again for the T8 for a coupler you can use the 8mm pineapple or the aluminum one. We used to use the pineapple on the 5/16" allthread as a 5/16 coupler was many times more expensive as it is not a common part.

The table does not need to be level for any use, the machine and the top need to be parallel but level does not matter.

Rounding the table up is a bad idea, Sounds like you are very new to all of this. I highly suggest you do not build your first machine larger than 24"x24" outer dimensions, not work area. You can use all the exact same parts and not need to spend another penny to just build it small first and only expand it later if you really really feel the need. The learning curve gets much more difficult the larger the build, small is easy, trust me.


Power supply, 3 prong plug cut the end off, yup.



I made a reply but it timed out and I wasn’t logged in any longer.

Basically, instructions are much clearer now that you said that the instructions included methods for leadscrew or all thread.

If my counting is correct, I will need two spacers (one as is required plus one to replace the nut lock spacer).

Then I will just need a coupler from you in addition to the leadscrew.

Why would rounding up the table be bad? In either build case (a 12" square working area, which is just short of your recommended 24" build size, versus the 24" square working area), the table is a few inches shy of 24" or 36".

Thank you.

On the sizes, the smaller it is, the more rigid it will be and the more tolerant to mistakes it will be. If you’ve never 3d printed or used a CNC, then there is a lot to learn. It’s much better to build it small (and probably pretty short too) until you get through a least a few operations. I personally think this is especially true for 3d printing. You’ll want to do small projects first anyway. They will give you experience faster than the big projects.

The machine is very changeable, so don’t worry about needing to change the size later. It can be done very quickly. If you’re going the conduit route, then just cut your first pipes small and buy more when you want to grow. If you’re doing stainless steel, then you could just leave them long.

And welcome. I agree with you. You should have a lot of fun with this. I can’t wait to see what you’ll build.

Aren’t San Francisco and San Diego the same place? :smiley:

My surfboard has dust on it instead of sand, pretty similar just subtle differences like that.

Still not sure why making the table larger than the minimum would be troublesome.

Sure, San Diego and San Francisco may be similar, but I think you would be put in the same place as the people that call SF Frisco or San Fran (natives don’t like it).

Sorry. if you mean the table itself, no problem, as big as you want. I assumed you meant the machine.

No, the machine will definitely be precise. Thank you, it may be easier to build the table to size, even if it is larger than the work area. I’d like to enclose it later on to keep the garage clean.