Slipping Gears on Maslow

HI I have been calibrating my mazlow cnc and the gears kept on slipping from the chain is there any way to solve this problem

P.S. This is the 7th grader Fino


This is my original acount


What frame design are you using? Top beam? are you using top or bottom feed (i.e. do the chains that go to the sled come from under the gear or the top of the gear?

Also check that the chains going to the sled are parallel to the cutting surface.

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If the chains are slipping, then you need to adjust things so that the chains
are parallel to the workpiece.

you should first adjust the height that the chains attach to the sled so that if
you hold the sled in mid-air by the chains, it hangs stright, or with the top
tilted slightly towards the workpiece

then you want to make it so that the chains are parallel to the workpiece going
to the motors. If the motors are too far out, you can adjust this by using a
thicker piece of scrap behind your workpiece, if they are too far in, you will
need to alter your frame to move them further out.

David Lang


Hi @Onif, chains skipping over the motor sprockets is one of the common problems while getting a Maslow frame aligned.
I would suggest starting with the sled with the weights and router installed and lift it by the chains to verify that the sled hangs with its surface about parallel to the frame work surface. If not, adjust the ring until it does. That sets the height above the work surface for the chains. Now with the sled back on the worksurface, look at the arms holding the motor mounts and adjust/alter those to bring the chains parallel to the work surface. Then make sure the motor brackets are very firmly attached so the sprockets are parallel to the work surface and the motor brackets won’t move when there is tension from the chains pulling hard.


Try this, for my configuration work fine,

but do not tighten the screw too much so that it rolls with the chain

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Is the distance of the motor sprocket and chain, to the sheet, the same as on the sled?
On slack chain side, align chain with sprocket.

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I for got to put the white piece of plastic on the motor


If you are still having problems, do what @Gero said and make sure both sides of the chains are parallel with the work surface BEFORE adding hardware in attempts to remedy the situation. This will prevent greater damage IF something goes wrong with the white piece, and will make your Maslow last longer (preventative maintenance). Even if you add the white plastic piece, If the chain twists enough or is not on the same plane due to skipping adjustments, it can stay seated in the sprocket and roll the slack chain underneath the opposite side of the sprocket when rotating clockwise. That felt like a lot for one sentence so I drew a very primitive sketch of it to help get the idea across.

Good Luck. What your doing is awesome! Keep it up and don’t forget to show us the amazing things you come up with.


I solved the chain problem:

The cooling issue that has the motors going crazy is also solved and I’ll be listing that in a day or so.


Nice idea.

One cause of the chains coming off for me was the controller overheating and losing track of the position

I don’t think this is a valid statement. The firmware runs on the mega that sits under the motor controller. To my knowledge the firmware has no current sensing and will never know if the motor driver chip is overheating. A overheating chip can cause a loss of position, but that will not cause a chain jump.

The chain jumps happen because of non-alignment of the chain with the sprockets.
Generally it could be that the sprocket is not parallel to the workpiece.
On the slack side (bungee) a not aligned chain will cause jumps while feeding out.
On the sled side the miss alignment is caused by the motor sprocket not being the same distance to the workpiece as to where the chain mounts on the sled. Jumps happen while pulling in.

What worries me about this design is the wear and tear. Metal on metal will have a ‘sanding effect’. The guard and the chain will become thinner over time, I guess. Pressing rubber wheels with bearing at the same 2 spots might be an approach to solve that.

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Hi Gero,

It’s two separate issues but can cause similar issues…

The Stainless Steel guides keep the chain on the sprocket and are a softer but highly wear resistant metal so they don’t wear down the sprocket.

They flex as the sprocket turns and keep the chain from coming off the sprockets. (especially useful when taking the sled off.)

The other issue is that the IC’s on the controller board stop powering the motor when they get hot, meanwhile, the sled keeps moving by the side that hadn’t overheated yet.

If the sled is at the top, moving sideways, you can easily see how this just pulls the two motors together, wreaking havoc.

This creates a situation where the chains are under so much force that they jump off the sprocket violently as the whole frame releases storing the energy from flexing.

Unfortunately when the sled is at the top it’s generating the most heat in the controller IC’s and it’s also easiest for the chain to come off.

In the attached photo I was cutting letters from a full sheet and EVERY TIME at the top center it would overheat and mess up.

A couple of times the chain got stretched very tight, pulling the sled way too high and was flexing the frame until the chain fell off because one motor had stopped.

So now I have a sturdier frame, the chain guides, and a water cooler on the control board.

I’m editing photos now and listing the water cooler later today.

(I’ll send a link when it’s up.)

I was on the website looking for revisions of the controller board to see how many different cooling block I need to make.

The one I have now fits v1.1 and I am waiting to here back about future plans to reorient the components (again).

Here’s the link to the Water Cooler & Chain Guards:

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I dont know if I know lol, but it sounds to me like maybe you need to raise the height of the motors, @Tim_Dodge? they should never pull tight enough to cause over heating of the motors or the IC, IMO, and even if they did GC would throw an error immediately when one motor stopped, then stopping the other motor and pausing the cut. that’s my experience anyways. I would like to see the water cooled setup, sounds awesome.

Let me stress again what I do know. mechanically/physically over engineering a solution for something that only needs to be adjusted properly, will most certainly end in excessive and/or unnecessary wear at the very least.

…or failure of the next weakest part…


Not sure if I replied to this in another so or not so…

The IC’s are rated to dissipate 25 watts of heat but the heat sink without
a fan can only dissipate 4 watts and with a fan, 14 watts. The water block
would allow for up to 120 watts of heat to be dissipated but that’s beyond
the IC’S current rating. So it’s not over engineered, it’s actually
necessary for full power operation.

I’ve stated this elsewhere - I run with no “white plastic bits” , my setup has never skipped inside the work space. Proper alignment with the work surface allows the chains to ride over the gears and move as they need to. Trying to force the chain to go over the gears while mis aligned is a loosing battle eventually something is going to give. Force is not the best solution in my opinion.

I’ve never seen an example of this method on another machine.

Thank you