Diagnosing Hello World

Thanks for this thread. My Hello World worked but I couldn’t cut round circles in plywood. I happened across this thread just coincidentally and loose set screws on both y-axis motors was my problem. Now the machine is cutting perfect circles.


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Glad its working better for you now :slight_smile:

I just finished building my Shapeoko XL, and I am having problems with my “Hello World” looking similar to the “bad” pictures in this thread, and my test circle cuts are off as well. So, I’m glad to see potential solutions listed here. However… I am a newbie, and I don’t understand what the fix is! In the picture that Richard Counoyer posted, it is not clear to me what in the picture is being referred to as the “set screw”, and what it means to be flat. Someone else then mentioned this: “my carriages arrived from C3D with the set screws tight but not on the flat.”

So, can someone please explain a little better exactly what is being referred to and how it should be adjusted? I would appreciate it. Thank you.

The motor axis are not fully round but have a flat part. This is where you want the setscrew (the tiny screw in the pully you use to fix it on the motor axis)


I just found out that the Canada dist. (Sparkfun) is selling old stock and the motors DON’T have flats on them. This photo is for a kit that was delivered last week So the answer might be to CHECK for flats, etc…

Image here


set screws are the small black screws in front. Two are used per pulley

Mystified by why one has a 5mm bore though.

Thanks for the several of you that replied. I think I understand what everyone is saying. Basically, there is a flat portion of the motor axis. A tiny screw (which is the set screw) goes into the side of the axis perpendicular to this flat spot.

Now my problems is that I don’t see any tiny screws to use! I looked through all of my stuff, and don’t see them. It is possible that the screws were very tiny and I possibly did not see them in a bag and the bag may have been tossed. Can anyone point out what item they are on the Bill of Materials link that Bill Adams posted? Otherwise, I’ll contact support for the specs to see if I can get them from a local shop somewhere.

Thanks again for the help. I’ll post another message when something changes to let people know my status.

They could be in the pulley’s threaded holes. Can you confirm?

If you have one of the later, preassembled machines, the pulley set screws should already be installed

On the older machines they were with the pulleys in a bag.

they’ve been known to vibrate loose and be lost though. They’re a commodity part and any hardware store should have them.

The first time I looked in the holes I thought they looked empty, but they in fact had the set screw in them. I rotated it until one was perpendicular to the flat and tightened it down and that’s how I got it finally working. I seems this is a somewhat common occurrence with the preassembled units.

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The root cause of this problem is that the people assembling these machines are not being informed of this problem, because we see it repeating week after week. Apollo, Edward, Rob, how about some feedback on this problem?

It would help if everyone would remember that this is a kit, and that one should check the machine before each use:


Are the screws so tiny that they would be recessed into one of the holes?

Yes, yes they are.

(and yes, Phinneas & Ferb is one of the few shows I watch)

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It’s fair to remind people that it’s a kit that’s true. At a minimum though I would say the revised instructions for assembling the semi-pre-assembled version should include checking the set screws, since by not building the x/y/z assemblies you never do that step in the first place. It also never hurts to mention to the assembly people that it’s apparently a not uncommon issue.

That was the only major thing I was disappointed with, as Carbide preassembling the complicated parts was supposed to save me assembly time, but because I assumed I didn’t need to check their work it in fact took far more time for me to get it running than if I’d assembled the motion assemblies myself.

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Agreed. C3D was trying to save us time by pre-assembling, and I appreciate it. But in my case at least that probably backfired, by introducing the set screw bug hunt.

OK. The set screw on the x-axis motor was not “on the flat”, so I was able to adjust that. All of the others appeared to be OK. It does seemed to have helped. Below is the the after version of the Hello World. (They will only let me post one picture, so I can’t put the “before” in this message). It is off center, but that is my fault.

Still not perfect, but a lot better than it was. I’ll try cutting something now.

Thanks again for everyone being patient and explaining things to me.

I’d double check the Y axis on both sides but yes that is looking good

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Check your belt tension if the oddities weren’t caused by the paper shifting.

Here is my latest version. I tried tightening the belts as I have seen described – so that in the middle you can lift it up about 1/2 inch. However, still not getting perfect results. Not sure what I need to do this point for fine tuning…