Questions / feedback about assembly instructions

Hello everyone. I’m new to CNC, and I hope MPCNC is not too ambitious for a way to start. I don’t have access to a 3D printer, so I ordered the parts bundle and 23.5mm parts from this site a couple of weeks ago. Vicious1, thank you for the design, and for shipping the updated roller parts so soon after you released the update. I can see how they’re a big improvement over the old design.

Since I’m going into this blind, I have a few questions/comments about the assembly instructions. I think I’ve gotten most of the parts together correctly after a lot of staring and a little trial and error, but I’ll ask anyway to make sure.

  1. Rails: You mention the recommended starting size, but it was unclear to me whether that size is to cut the X and Y rails to 30" or if it’s to plan around a usable space of 21" x 21" which is mentioned on another page (I forget which). I did the math on 21" x 21" and it seemed to work out to just under 20’ of EMT, so I went with that and it seems to have been right, but for other noobs you may want to consider clarifying on that page.

  2. Rails: Thank you for the recommendation of the conduit reamer; I had an impact driver already and it made things easy. I didn’t have a good way to cut the conduit squarely though. but after some research I got a “MAGBIT 801.114C MAG801 Tube Cutter Copper/EMT 1/8-Inch - 1-1/4-Inch Cut” from Amazon. I understand it wouldn’t last through a lot of EMT cuts, but it got through the cuts for one MPCNC just fine, and I was able to make the cuts very precise. With the reamer to soften the edges it worked great.

  3. Rails: If the “finish” on the conduit makes a difference, it may be worth mentioning on that page. I had bought and cut all of mine before I saw discussion of it here in the forums, so I’m hoping I didn’t mess up by using the non-shiny stuff I got at Menard’s.

  4. Roller Assembly: The page doesn’t have instructions for the new design. Hopefully I got mine right based on looking at (and you saying “no washers” helped).

  5. Corner Block: The instructions say to insert the leg and snug the screw, and also has instructions on inserting the X/Y rails and tightening the screws on those. But later in the Frame instructions, neither are inserted yet, so that was kind of confusing.

  6. Corner Block: It may also be worth mentioning how the top/bottom pieces are supposed to be lined up with each other.

  7. Frame: My build is paused because I ran into the same problem some other users here did: I don’t have a screwdriver capable of reaching the feet screws without also bumping into the corner blocks. :slight_smile: Might be worth mentioning that you’ll need a small stubby screwdriver, or one of those right-angle ratcheting ones.

  8. Middle Assembly: My bundle came with two Nut Lock parts - is that normal? It caused me some confusion at first during this step.

  9. Z Axis: My bundle also came with two Pineapple Couplers. I’m glad, because I felt like I was going to break it when tightening the screws. Anyway, it wasn’t clear from the instructions how tight those need to be. For example mine is tight enough to turn the allthread, but if I hold the allthread still and turn the coupler it will still rotate. I assume that will be too loose? Should I keep tightening gradually until I can’t do that anymore? I also didn’t find/feel a middle ridge when I was sliding the pineapple coupler onto the stepper shaft, so I had to kind of eyeball it and get it halfway manually.

  10. The rest: I don’t see anything in the instructions about mounting the belts and connecting the electronics and stuff. I’m pretty sure I see how it all goes together, but I’d like to be sure at least about mounting the little parts onto the roller stepper shafts. Can anyone provide a little guidance there? It’s probably something most people know already before starting, but like I said, I’m brand-new. I also don’t see instructions for mounting a tool onto the Z Axis assembly, but I haven’t really tried that yet; it’s probably pretty straightforward.

Thanks again, and I hope my questions/feedback will help make the project just a little more noob-friendly.

Awesome thank you. The updates have been rolled out slowly and I usually have been updating the machines I already have, so I didn’tt notice until last week that the assembly instructions were out of order and needed an update so I reordered them a bit, and updated the calculators. I have a full machine ready to build and update things step by step and I get in here everyday ready to start and things keep getting in the way. Soon.

Just a few quick responses to get you going,

1-I hoped the calculators would clear this up, I’ll take another look.
2-Nice until last week I just used a hack saw, Then I got a cold cut saw…freaking amazing.
3-Finish doesn’t usually matter, the zinc wears right off. With the release of the new size we have been opened up to the possibility of stainless steel tubes, perfect finish and a bit more rigid.
4-ASAP, I realy need to do this today but now it is kind of out of order, the motors go on last after the gantry as best as I can figure.
5-Same as above, New parts new assembly order. I just caught up on everything since the release yesterday. I should build a table today and get started.
6- no problem I will add it.
7-I used to pre-drill at an angle and use a regular screw driver. The last feet I replaced I pre-drilled and used stacked screwdriver extensions, pretty much the same thing. Pre-drilling is key to making this easy but I really have been trying to design new feet but these seem to work better than anything else I have made.
8-Yes, you should be using the smaller one. Two parts in case you are not using my hardware and get the larger couplers.
9-Same as above smaller one, the larger one fits 8mm rod. You should be threading it in without the screws in, and then tighten up the screws after. It really shouldn’t move but you can add super glue or locktight if you are worried. I thought that was in the directions, I will have a look.
10-I thought the pulleys were in the roller section. I’ll get this in the update for sure, belts and ziptie orientation.

Thanks for keeping track of the issues you ran into.

I’m not good with the web side of things, so they take longer to fix. If I could only build the site in solidworks I would be set. I got a late start this morning because I was trying to map out a better site flow and layout. This project went from a thingiverse upload to my full time job so things have sort of come together piece meal as people needed the info and it is now starting to show in this jumbled mess. My previous priority was fix the common hardware issues people other than me had, get it easier to build and square. Now that that is done/better than before my new priority is instructions with a new layout.

Wow, thanks for the quick and thorough answers!

  1. The calculator looks good, but doesn’t clear up what is the recommended size mentioned in the instructions (pretty sure it’s 21x21" though). Also I forgot to mention: the calculator shows both X and Y rails as the same length, but the cut list shows the Y rails 0.2" longer. Which is correct?

  2. Crap, if only I’d waited a week or two. Stainless would be pretty cool.

  3. Ah, I hadn’t thought about pre-drilling at an angle; I just went straight down.

  4. Hmm, I didn’t realize they were different size. That would probably be a good thing to add to the instructions as well. Pretty sure I used the correct one; the coupling nut fit into it perfectly.

  5. Also didn’t realize they were different size. I probably have the wrong one on, as it slides right in. :’(

I understand completely about not having time. I’m pretty handy with WordPress, so if you’re fighting with anything I may be able to help.

1- fixed thanks, +264. I haven’t put up a new recommended size yet, so you must be seeing the old dimensions from somewhere. I would make your machine as small as possible paying particular attention to the leg and Z axis height. Bit are generally 1.5" of usable bite so really anything over that is material height, more is not better.
3- well see I have a lot of it sitting here waitng for the build in different wall thickness’ well see if it is really worth it. I am going to guess for milling not worth it, laser picture engraving and 3d printing probably worth it, anything else conduit is fine.
8- I just recently added both sizes, took a note to fix this.

Hi I’m upgrading from the older parts related to question #4 on post 15215. What parts do I need to print as “C-RollerMount.STL” doesn’t simply replace “Roller_Motor_Mount.STL” this is for 3/4" emt. This has been working great except a few glitches which I suspect are software related but I want eliminate everything else first. Thanx for all the work. I bought everything from you except the printed parts and emt, this IS the way to go it was a good deal!


The parts with the “*” on this page

Two more questions, hopefully the last ones:

  1. I have all the tension bolts finger-loose, but the middle assembly still feels tight on the conduit, and the rolling is “bumpy” rather than smooth, and makes the table vibrate when I push the assembly in either direction. Could I have done something wrong during assembly, or might it just be my conduit? The side rollers all feel this way too. I tried sanding all my X rails with 100-grit wet paper as someone suggested in another thread, but it didn’t seem to help. I didn’t have very much time so I didn’t get it shiny-smooth though so I’ll try sanding it more later. But I’d appreciate ideas if you have any.

  2. My bundle came with eight 1.25" washers and eight smaller dark-colored washers. Where do these go? I’m afraid I can’t tell, even in (in fact I’m not sure what’s mounted on your stepper there; it doesn’t seem to be anything in my bundle?). I also got a small jumper with a resistor, is that for people using other parts?

I think I see how everything else goes together, but I can’t puzzle out those pieces and I don’t want to leave them out if they’re needed. If I can figure them out and get the motion/smoothness thing corrected, my build will be ready to go! Thanks again!

1-Usually that is just the zinc galvanizing and it will flake off all by itself, not usually a big deal. The tension is supposed to be snug without any tension. It will relax a bit now that it is assembled but only tighten it if it needs it.

2-don’t worry about the washers those are for the old configuration. The resistor goes on the t0 terminal unless you have an extruder. This is shown on the ramps page of the assembly instructions.

1- make sure you don’t have a bearing riding on a seam, that tends to be very rough. Just have a look at it and turn it to where are 3 bearings are riding on the smoothest pat and it should smooth out real quick.

I managed to have three of my rails arranged so a bearing was on a seam - thanks for mentioning that. Hopefully I can finish assembly tonight.

One more last question - one of my pulleys seems to be missing one of the two tiny screws that secure it to the stepper shaft. It doesn’t feel like it’ll be a problem but I wanted to see what you think.

As long as you get it on the flat you will be fine. Some of the screws are really short so it might be in there just really deep. If not no big deal.


You know none of us here believe that…video or it didn’t happen

I hope you like pure, childish joy:

Nice! Now I believe you, and I added you to the videos page.

Tighten up the belts a bit and you look pretty solid. High five!

Tighten up the belts a bit and you look pretty solid. High five!

Out of curiosity, how tight do the belts have to be?

Tighter than that but not too tight.

Kidding, I’m kidding

I’m not sure how to describe it with out a belt tension gauge. Not as tight as a bass guitar string? the zip ties will start to take on a square-ish corner.

Haha, yeah, I didn’t notice how loose that one was til I was watching the video. I assume it should be pretty taut, like just about any other belt?