Stop throwing your nuts!!!

Yes, the metal lever appears to provide enough resistance to give the mechanism pause until the other side drops a bit more and pulls it down. Pushing down on the chassis at the right time or adding weight activates the switch properly.

Either the lever is stiff or the actuator, itself, is stiff.

I could give it a squirt of WD40 to see if that helps, but I think that I will finish my current round of prints before I try that.

 

I was having unreliable z adjustments. I noticed that the screw was very close to the switch fulcrum. I removed the switch (and found that the screws were loose). I swung the switch 180 deg and now the screw hits the lever in the middle. I have a question. To level the bed I turn the z axes screws independently. They turn very easily. What keeps them in sync? I would think that they should be tied together so that the level to the bed doesn't change.

 

Please don't use WD40. It's a horrible lubricant and really acts more like a degreaser that displaces water. It ultimately attracts more stuff than it lubricates. :/

Use a light machine oil. I personally use T9 by Boeshield. It was made by Boeing for Aerospace and, having used it for years, it's an excellent lubricant. Specifically I use the "bicycle" version of the lubricant since it has a nozzle that can be pierced by a sewing needle to apply individual drops where I need it. A little bit goes a very long way. T9 is my lubricant of choice for many applications.

Here is their website.
http://boeshield.com/

You can find it on Amazon.
http://www.amazon.com/Boeshield-Cor...1_3?ie=UTF8&qid=1386617109&sr=8-3&keywords=T9

 

Grease works too. I just hate hearing when people use WD40. Makes me cringe.

 

I have some Bell bicycle grease as well as some sewing machine oil. I actually usually use WD40 just for cleaning.

I was wondering if I should put some grease or oil on the guide rod. Perhaps it is not as slippery as it should be.

FYI, I continue to print with the added weight, and the printer has thrown the nuts only a couple of times with it in place. However, that the nuts would drop even with that extra weight does indicate that there is a problem, somewhere.

 

My micro switch took too much pressure, so I replaced it.

The problem still happened. Why?

Because the cable for the stepper motor on the Z axis is too short! As the Z axis drops, sometimes the cable is what causes the whole Z axis to hang, just enough to not drop to set off the limit switch.

I rearranged the cable bundle a bit, and now the problem is gone.

The other issue I was having is not setting up the z axis clearance without first preheating the extruder, which gets longer when it is hot.

 

I will have a look at my cable bundle whilst it is homing. I had wondered about that, but I figured that the design must have taken that into account.

 

Hello everyone.

I went though all of the tips here trying to stop throwing my nuts, but I kept having issues.

What I realized was that the nut was throwing itself before the Z-stop was even touching the switch. The culprit was that the X-axis stepper motor was pinching the wire bundle that goes to the extruder, so half of the whole assembly couldn't go down any more! One I move the wire bundle out of the way - no more issues!

I may be missing something, but what is the reason for switching the z-stop switch so the z-stop bolt hits the lever and not the actual switch? Is it because actuating the switch was taking too much weight and the extruder would keep going down until enough weight was applied? If not, the lever will have 2-3 times as much play as the actual switch, since the lever has to travel a lot farther distance to actually trigger the switch. I've turned mine to match what the consensus is here, but I'm skeptical as to whether or not it is creating the issue with the slop space in the switch between activation/deactivation.

 

thanks for the explanation and help. I saw what people had done with the weight, and thought I had the same problem until I realized that by removing the hood and putting it back on, the cable bundle was pinched and that's why that whole side of the unit wasn't dropping down properly. Before putting weight on the unit, make sure that it isn't getting pinched and that the rods are lubricated.

either way, seems really good now - starting to get good adhesion with heated bed and vinyl without hairspray. Still haven't made it through a print yet, even the 15mm cube, due to things getting stringy or not extruding halfway through. I'll find the appropriate place to post more info once I run through all of the threads to test out some options, first.