Maslow Accident to be Learned From

Ok , so myself and a friend were running through the Calibration process on my new Maslow. We were at the point where you run the chain from the left motor over to the right motor for measurement, well evidently my mounting location for the chain was to far away from the motor and when the Bungee sprocket reached the chain mounting nail the mounting nail for the chain was pulled out and the bungee shot across the machine with the sprocket hitting me in my right hand.
I suggest that an actual measurement for that mounting location be added to the build instructions. Also a better way to mount the end of the chain other than just a nail may be a good idea.
I just wanted to post this so that others don’t make the same mistake I did. Now if I could just find that sprocket that hit me I could try to fix my Maslow.!

Left side

Right side
My Hand

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I’m sorry, that looks painful! Let’s fix it.

Suggesting a measured distance to place the nail is a good idea for making sure that doesn’t happen. I’ll add that to the build instructions right away


Another quick Idea I had was that, my friend didn’t even realize there was a Stop button on the Calibration page. So maybe you could turn all the machine Stop buttons to Red so as to make them stand out in the Ground Control software. Other than that I love my Maslow and I know you will all be seeing me around here. And as far as my hand goes it looks worse than it feels.


That is an excellent suggestion and an easy change. I’ll do that too.

Never worry about hurting my feelings, that fresh perspective you have right now is SO valuable. The rest of us are so used to the way things are that we can’t see the improvements which we can make. Keep em coming!


Will do @bar, and I must say I have been impressed with how simple yet effective the design of the Maslow really is, you Guys and Gals that figured this out are Amazing Minds to say the least, but I will add my 2 cents when I see a place for them. :slight_smile:

Now if I could just find that damned sprocket…


I’ve proposed the addition of a measurement for the placement of the nail in PR #1

Feel free to vote on it if it looks good!

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2 washers or a bobbin from a sewing machine do the trick while waiting till a new sprocket is found :smile:


Noob question, why a nail? Nails are for sheering strength in wood, think downward force of you walking on a deck. The joist hangers are nails, perpendicular to the top of the deck but parallel with your foot. A screw however is designed for the opposite, holding power in the same direction where you don’t want things to pull apart. In this case, a screw would have prevented the issue.
A tangent, this is how you tell a quality drywall job. Nails may be cheap, but you aren’t holding the drywall from sheering off the wall, you are keeping it from pulling apart.


Understanding the best fastener for the job is key in success. My father worked in Areospace fasteners so I got a special eduction on them.

Thank you

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Cheap and simple, the forces on this are supposed to be almost nothing.

@dlang Once you add the Bungee to the chain you then are adding force on the nail, the farther you pull the chain the stronger the forces on the nail produced by the bungee. When you are calibrating the machine you have the bungee pulled a long way and applying lots of force on the nail. I have been trying to think of some kind of simple “double stay” for the nail so that even if the nail comes loose the chain is still held by a back up attachment. I will add pics when I have it figured out.

Maybe something like this image

Found the item here

This is why I’m a big fan of eliminating the bungee and using a couple pounds of
weight instead.

the bungee is applying the most force when you need it the least and the least
force when you need it the most.

weights apply a constant force, adjust it to match what you need for the
worst-case and it won’t apply more force than that at other times.

David Lang


I believe I read something about the weight system, and I agree it makes a little more sense. What would the needed amount of weight be? I think you could use a wire dog lead and connect it to the weights and then drill holes through the center of the beam routing the wire through the holes to the weights. A little wax on the wire lead would allow it to slide freely through the holes.

you can use simple rope/parachute cord and route it with pullys

I believe it’s only a few pounds, someone did it with soda bottles filled with
damp sand, but I don’t remember what the weight was


Yes! I used a 2.5 lb concrete brick for each side and that works well. There are a LOT of good ideas on this.

@MakerMadeCNC, are your kits using bungees or weights?

We are currently shipping with the bungee, but looking into transitioning to providing pulleys for a counterweight setup.

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I use 2 liter pop bottles with water in them. Easy to adjust the weight, just add or subtract water to get the weight you need. Drilled a hole through the cap, threaded paracord through the hole and tied a knot. Put cap back on the bottle and ready to go.

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I have a solution for the nail. I put mine in then realized I needed to remove them for the calibration, which of course bent them. The “c” brackets I used are left over from wire closet shelving. So easy to get in wire closet shelving section of hardware store. Chain fits perfect and then cotter pin to hold. Although I will probably trim cotter pin to prevent any chance of snagging.

Or flip it 180 degrees and let the chain ride on the round part of the “R-Key” instead. Would definitely be better than the straight post. Just my 2 cents. I like the bracket idea Snapperhead posted, that really looks promising, and it’s designed for chain. Now to just find it in #25 and we’re set! +1 on that find for sure!