End stop switches stripped

[mrjohnk 0]

I'm about half way through the build in my machine. Overall it is going well. Near the beginning of the build, I did encounter some issues related to the mounting of the end stop switches. Two of them had threads that were stripped out, therefore, would not tighten down snug. The inclination is to think that I overtightened them, however, I do recall that they never gave any resistance once the screw was fully inserted.

I'm considering my options on how to move forward as the switches will not stay in place on their own at this point. My next plan is to grab some surplus course threaded screws and see if I can get that to link up without having to modify the holes in the wood. Are there any recommended remedies? I imagine this is fairly common.

Thanks.

John

[fuchs 0]

I had the same problem with 2 switches where one screws didn't really catch and with the top Z-Stop where _both_ screws were loose.

As i had to readjust the Z-Stop a few times, i was very worried about that condition - until i used some longer screws than recommended in the wiki. Magically, the longer screws (at least for the Z-Stop) did work wonders and both threads really gripped.

So maybe try some longer screws (16 instead of 12mm or 20 instead of 16mm etc.)

[jsamuels 0]

I believe it is okay to use a screw that will fit through the switch, with a nut on the back side to fix it. But use caution to not over tighten the screw, as it will crack the switch.

[lobster2b 0]

I had the same problems, ive used the longer bolts and used nuts to make them really secure. though there is very little room because of the belts axled and pullies, ive printed with it for some time now so it works.

please bear in mind that when you mount up the electronics, one might be reversed.

[SandervG 1,521]

You could use a slightly longer bolt and a nut to tighten the end stop.

But if you ever want to make some changes to the position of your end stop after assembly

putting the nut back is very difficult because practically everything will be in the way..

You can also contact support and we could replace your end stop.

[fluxline 0]

@sander

I also had two switches with stripped holes, and I am sure they were when I received them because I checked before install. Not difficult to solve so didn't bother support. But, I think there is a problem in your line or supplier that you might want to hunt down the root cause.

[SandervG 1,521]

You are very right and i have put it through to our production department to keep an extra eye out for this.

It is something that comes from our supplier.

Alltho it is not a very big problem it can be annoying.

Have you been able to solve it with a nut or did you fix the stripped holes?

[fluxline 0]

This probably screws my warranty but here goes for the easy fix without tapping new ones:

1. some PVA glue on a small brush, put it in the stripped hole, just a tiny amount

2. some machine oil on a bolt to match and run it slowly in the hole

3. let it dry a bit, slowly unthread screw, let dry a bit more and your good.

edit: just a very small amount of glue, very small. a lamp helps it to dry. I was lucky it wasn't on my z axis, don't think it would take many uses.

[jsamuels 0]

Sander, my Ultimaker (order #100003698) also had some limit switches with stripped threads. I'm certain it came like this from the package, as after the first stripped when I barely tightened it down, I checked the remaining carefully and found the issue. I was able to fix it myself with an M4 tap and screws, but not every owner would have such things readily at hand.

You may want to consider changing to a limit switch made of a more durable plastic or ideally one with metal insert for the screw thread.

I might also suggest changing to a slightly longer screw here, as the 10mm or 12mm+washer on the Z limit switch does not fully extend through the part, limiting the thread engagement length. This increases the potential for the thread stripping out. You may also consider a flanged button head for this application, it should provide a more secure mount. An M3x12 flanged button head possibly?

[joergen 2]

well, in the short run you would like to print a z hight adjuster from thingiverse anyway, so the stripped thread doesn't matter so much. you can also switch it for the bottom z switch, which is almost never used.

[jsamuels 0]

Actually, you can't easily swap the Z axis limit switches as the cables are different length. And in my case it was an XY switch that came with bad threads.

[SandervG 1,521]

Thank you for your suggestions and solutions.

I don't think there is any harm in using a slightly larger bolt for the end stops.

[Daid 306]

Might be a problem at the X endstops, the sliderblock seems to get very close to the endstops.

[SandervG 1,521]

I don't think if you would use a 12mm instead of a 10mm it would cause any harm.

After all, the end stop is meant to put a stop to your sliderblock

[mrjohnk 0]

As an update, I was able to get through this without much fuss. I just grabbed a couple of the longer bolts that were left over from the assembly and used those. They worked great. I think if you could just change the instructions and kit to use these longer M3 bolts, it would solve most of the issues. You have to be a bit careful not to go too long as one of them is very close to the sliding axis that runs from front to back above one of the steppers. Luckily, the substitute bolt extends all the way through the switch and hangs out the other side, but does not impede the axis motion.

[calinb 11]

I had a switch that was provided with partially stripped holes. Fortunately, it was one I could swap with another one and "flip" the bad side with the stripped threads over.

[calinb 11]

The bolts can be easily cut to custom lengths with a Dremel tool and small cutoff wheel. Screw a couple of nuts past the cut line first--just in case the threads need some cleanup near the cut afterwards. Put a drop of oil on the end of the threads after cutting but before removing the nuts too. I've found the threads usually remain very clean and nice, if a fine cutoff wheel is used with a steady hand and low cutting force. The extra precautions to "chase" the threads afterwards are not necessarily required.

One place that I found cutting bolts to be indicated was the the hot end assembly. I shortened two of the four m3 studding bolts holding my hot end together (the ones not retaining the fan), because I preferred the orientation of the aluminum heater block, as depicted in the older Rev.2 instructions:

The left side of the hot end is facing up here:

The heater and TC wires are more relaxed in this position, I think. However, if the aluminum block is assembled in this position, the new longer m3 studding bolt in the right front corner interferes with it. At least this one studding bolt must be cut. I cut the one in the back left corner too, because a shorter length is more appropriate and better looking!

I changed to this configuration when I reassembled my V2 hot end after a tear down to search for signs of plastic leakage inside my PEEK. I wanted to correct the tendency of the binding heater power cable trying to twist the aluminum block and unscrew it from the brass tube or rotate the peek in the aluminum plate. Now that my wires are completely relaxed in the new orientation, my aluminum block will tend to stay put.

[jsamuels 0]

What version of the ultimaker is this? The hole in the bottom plywood is different, and so is the aluminum plate...

[calinb 11]

What version of the ultimaker is this? The hole in the bottom plywood is different, and so is the aluminum plate...

It's a rev.2:

http://wiki.ultimaker.com/Ultimaker_rev ... usion_head

I have the latest model with the V2 hot end, but no Bertho drive mod yet. I just liked the way they positioned the aluminum heating block and routed the wires in this rev.2 wiki so I re-configured my new re.3 in this configuration when I re-assembled the hot end after a tear-down to debug my feeding problems, which are now solved.