3D Printed Grass Trimmer (MPCNC Printed)

You have a 3D printer? A Dremel ? Some tubing and a few hours of your time?

Then why don't you build your own grass trimmer?

Who said "because that is a stupid idea which has no point whatsoever" ?

Well, indeed, but it is fun!

You don't need much things to build this, provided you already have the tooling:

-A 3D printer, obviously. I'm using my DIY MPCNC, you can find more information about it there or in the MPCNC forum, here

-Depending on your size, a certain amount of diameter 25mm PVC or metal tubing. While a midget might be fine with 35 centimeters, be aware that a giant might require up to 3 meters. Creepy sized people like me, being around 1.80m tall will need about 1.50m of it. If you can, use some metal tubing as PVC tends to flex a bit under the load. Tubing is super cheap, it should not cost you more than 2 bucks in your favorite hardware store. It is generally used for coat hangers in closets.

-A Dremel,

-A Dremel flexible hose

-At least one of those diamond cutter wheels

-PLA filament, I think I've used about 300g in total, maybe less.

-A bit of nylon filament (I used some printable nylon filament for 3D printers, works ok)

-A few 4mm diameter screws.

You will find all the parts provided in attachment.

There are only 6 parts to print in total. I also included the STEP and Solidworks files for people who would prefer those kind of formats or would like to edit my designs for whatever purpose they want. You can use, reproduce, copy or modify my designs as you please, as long as it is not for evil. Please do not use these designs for evil purpose, first because you would be ridiculous threatening people with a grass trimmer, and second because evil is bad.

Printing is pretty much straightforward, I've designed those parts so that they are pretty much foolproof.

I've used the following settings:

-PLA plastic

-220 degree C

-2 perimeters

-30% infill.

-1.2mm nozzle.

I've used a pretty big nozzle for two reasons:

-It prints way faster

-The parts are way stronger

But basically any nozzle of your choice will work just fine, it will just take a while to print the bottom cover with a small nozzle.

It took me about 7-8 hours to print everything. As you will see, my 3D printed parts do not have a very nice finish, but the reason is that I was using a very big nozzle, I wanted to print as fast as possible and didn't cared at all about the looks.

First thing will be to cut a few centimeters of tubing, it will be needed to connect the bottom parts together.

Cut 10 cm of tubing, then slide it into the Y shaped connector.

Screw the wire guard to its little flange using 4 screws and, if possible, nylon locknuts.

Drill a 3mm hole on one side of the flange and insert a 4mm screw in it. The screw will have two functions:

-secure the tube to the flange

The top of the trimmer is composed of 3 parts:

-A U shaped part, which will be the arm rest

-The PVC or metal tube

-a handle

First, slide the handle into the tube and drill two holes in the flanges to pass some screws

Insert the screws and bolts but do not tighten them yet.

Second, insert the U shaped part, drill some holes in its flanges and insert screws, the same way you did for the handle. Then, align this part with the end of your tube and tighten the screws.

Finally, put your forearm on the arm rest, grab the handle, and move the handle until you feel that the position is comfortable, then tighten its screws so it cannot move.

Insert the tube into the Y connector

Make sure everything is well aligned.

Drill a hole through both parts, while keeping everything aligned and finally put a screw in there to lock everything in place.

At this point, it should look like a grass trimmer. More or less.

I wanted to make a nice little support for the Dremel, but as it turned out it was simply easier to use duct tape. Being lazy and cheap, I went for the duct tape option. But you can design some fancy brackets if you want, it's pretty easy.

Anyway, first step was to attach the Dremel to the tube. If you're using the same "ghetto" technique as I am, please pay attention not to obstruct the venting holes of the Dremel. This is crucial to your Dremel's lifespan as it will get pretty hot during operation, trust me!

Once done, slide the flexible hose into the top hole of the Y shaped connector, all the way to the bottom. Secure it with the bottom screw.

I've used those kind of dremel disks to attach the 3D printed part on it (see picture above)

Sorry, the only pictures I have are not showing the wire holder part. I added it later since it wasn't working well without it. Just print the wire holder part and you'll figure out how to mount it on the dremel, it is very easy.

Simply screw the wire holder on it using 2 3mm screws and nuts.

Cut a bit of nylon wire and pass it through the wire holder.

Finally, attach the wheel to the dremel like you would normally do.

As you can see on the picture, I tried first without the wire holder. It turned out to not work very well, the reason was that the nylon wire got wrapped around the disk shaft, due to the high acceleration or basically anytime it was hitting grass. The wire holder part solves this issue by preventing the wire to wrap up, due to the longer distance to the center.

Well, it is time to use this mess now. So, first of all, as you probably know already, Dremels are not really designed for that kind of application. They will generate quite a bit of heat and potentially die at some point, which, again, is totally normal since Dremel's engineers probably didn't take into account the fact that some morons may use their devices as grass trimmers. So, try not to use it continuously for more than 10 minutes straight. This is perfect actually, it's the best excuse to drink a beer without the wife suspecting you of being lazy. You're just waiting for the machine to cool down, it's not your fault if the machines are not able to keep up with you. Menawhile, you need to stay well hydrated.

Anyway, I was able to finish my garden, eventually. But I passed out several times due to over-hydration during machine cool-down.

Just kidding, my garden is actually super tiny, so it was pretty much adapted to its surface.

So you may ask, why building such a thing when you can probably purchase a brand new one from the store for about 30 bucks, while a Dremel alone worth the same if not more? Well, that's a good question for which I don't have any satisfying answer.

I needed a grass trimmer, I had an old Dremel and I wanted to try a fun project with my 3D printer. Plus I can reuse the Dremel anytime I want for other projects just by removing a screw, so it was not irreversible.

In the end, I still have a funny tool whenever I need, which can, both at the same time, cut grass and give my neighbors a good laugh!

PS 1 : Please forgive me if sometimes my English is not perfect or weird as I'm not a native speaker. Plus I'm kind of a weird guy anyway.

PS 2: Don't forget to vote for me in the contests if you found this instructable nice, useful, or just want to piss of my competitors.