Adjustable Z Endstop for MakerFarm Prusa i3v

by clough42 May 20, 2014
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This does not fit the MakerFarm Prusa i3v 8". The microswitch supplied has a shorter arm than the one pictured, and does not reach.

The photo, above, shows the part installed on an 8" i3v. Is Colin shipping a different switch now?

Yes, I found the same thing with my MakerFarm i3v 8". My switch has a small wheel on the end of the arm. The switch still has 2.5mm holes that are spaced 9mm apart. However, it seems the horizontal distance from the furthest hole to the center of the end of the arm (where switch should ideally be pressed) is 13mm. From your design it looks like your switch (the original design) is probably 17mm from furthest hole to switch arm "pad"?

Would it be difficult to stretch your design to move the switch holes over 4mm? I love the design and I think that would work fantastic with the latest MakerFarm i3v's with that tweak. Thanks so much for considering and please shout if I can answer any more questions about it!

Okay, so you need the switch to reach an additional 4mm further than it does now?

Yes, exactly. If the two holes for the 2.5mm screws on the switch mount were 4mm further away from the z axis extrusion then the switch arm should line up with the adjustment screw on the x axis extrusion. I suppose that the switch mount part might need to be elongated a little so that the hole isn't too close to the side.

Thanks so much for considering the change!

I just uploaded a longer version of the switch mount. Let me know if this works for you.

Great, thanks! I'll try to print it, hopefully today...

Finally got a chance to recalibrate my printer so I could print this. It works perfectly! Thanks so much! I took a picture and sent it up here https://www.thingiverse.com/make:149276.

Adjustable Z Endstop for MakerFarm Prusa i3v

Thanks for uploading the photo. It looks great.

If you place this on the left side it should work just fine it looks like it will. I did not try it yet, but I probably will, printing another z right now, if that does not work I will be using this.

This won't work on my i3v 12", either.

We just set up a lab with 24 i3v machines in our middle school.
I'm thinking these little doosiers are going to save the day.

This is awesome. Very repeatable Z adjustment. Great solution.
One of the first things I printed.

Just a note for others with the 10" i3v kit before printing this. Check the length of the V-Slot extrusion rails. This endstop mod will not work with the 10" bed kit I received because the V-Slot extrusion rails extend about 25mm past the X Idler vertical wood support piece. If the 10" kit starts coming with the V-Slot extrusion rails cut about 35mm shorter, or you are willing to cut the bottom rail about 35mm shorter, then this mod will work.

Hi RaySuave, do you have a recommendation then? My kit comes on soon. I am not going to want to cut the extrusions. I will measure to see if there has been any changes.

Use this, http://www.thingiverse.com/thing:437330

The guy who made this put the beveled surface on the wrong side but it still works fine.

Flat extrusion nuts solved. I put an M3 bolt in for the adjustor, but it turns out M3 bolts are almost not threaded long enough. I suggest using an M4 bolt 25 mm long that's threaded its full length.

This is a MUCH better way to set the z stop than provided in the Makerfarm kit.

Just printed these - great idea. How do I get the flat "nuts" that go inside the aluminum extrusions? Or did you use washers and regular nuts?

I had a couple of extras in my kit. You can also buy them from the OpenBuilds parts store. There are several versions available:


Thank you for these. Would it be possible for you to extend the limit switch out another 100mm or so? The adjustment screw doesn't quite reach it on my i3v. Thanks.

Hmm...I'm not sure I understand. Does the screw not line up with the switch, or is it just not long enough? 100mm seems like quite a lot.

The screw misses the switch just bearly. If the limit switch mount placed the limit switch a little bit further out from the extrusion it's mounted to, it would work. I actually hot glued a nut onto the end of my adjustment screw and the nut touches. I guess it doesn't need to be 100mm. Do you think the flex in the arm would cause inaccuracies over time? That's why I'm wondering if it would work better if the screw hit closer to the clicker.

As for inaccuracies over time, I don't really think that's much of an issue. The forces involved are very small and won't lead to much flex. You can deform the switch body if you tighten the mounting screws too much, and that can make the switch mechanism "sticky" so it doesn't always trigger at the same place, but that's the only issue I've seen.

Interesting. As you can see in the photo, it lines up perfectly on my printer. If you could provide a photo of your printer, it'd be easier for me to tell what might be going on. You can adjust the part with the adjustment screw in it left and right by loosening the 5mm screw and sliding the part in the extrusion.

Thank you for posting and designing these i3v components. I just got my printer running and end stops and level bed nut traps were the first on my list of things to modify and you solved them both very well. Keep up the good work!

Thank you! I've wanted this since I got the i3v...

I've learned that if your in a pinch and you have no immediate access to a M2.5 screw, you can use a T10 Torx driver to bore out the hole on the switch just enough to allow for a tight fit on a larger M3 screw (I have lots of extras from the upgrade). If you force a M3 screw through the switch without tapping or boring out, you'll probably end up splitting the switch (like i did). The T10 Torx can also be used to drive the M3 screw in. Not the right tools for the job, but if it's lying around...why not?
BTW this is a great design clough42. Thanks again!

This makes tuning the z-axis a breeze. I find it much easier to give this little screw a quarter twist than having to tweak my z-offset in my slicing program. I would like to recommend that people who use this use a screw that is at lease 25mm long. I tried using a 20mm screw and most of the screw travel is wasted clearing the wood part behind it. I would also recommend having a long hex key on hand as there isn't much space around the screw for a small tool.

Thanks again for creating and sharing this and all your other i3v work. You've helped me turn my printer into something much more functional than it was stock :)

Nice solution! I like your other Makerfarm specific designs as well. You're now one of my favs. You also got me turned on to the idea of using sorbothane. I printed the vibration dampening feet you had uploaded a few weeks ago and it made a huge difference. Thanks for sharing your designs!

I don't know if this is your idea or not but its great.

You're the best! Thanks for designing this.