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Forum - Troubleshoot modules (Step feeder & zig-zag lift)

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I worked on two modules (my 2nd & 3rd) over the weekend. I tried copying Akiyuki's Zig-Zag Lift module, using the ldd file here.

With this, I was having a terrible time with it not working nicely, till I realized I was using 87552 not 4864. The little side walls were a real pain. Once I fixed those, I still ran into the issue that occasionally two balls get in the lift and get stuck. Has anyone else built this? Did you see that problem? And if so, how did you fix it?

The second module I worked on was a simple step feeder module (or at least I thought it was going to be simple).

1) I had to add beams to keep the axles under the steps straight, else they want to wobble a lot and jam the steps. Because of this it is fairly high off the baseplate, and I'm struggling to figure out how to get it lower so I can match the spec of 10 bricks tall. So the question is, does everyone use beams, or technic plates to guide the axles to keep them traveling only in the vertical direction? Did others find a way to get them lower?

1b) I see from Akiyuki's video here that he was able to get one lower, by putting the steadying restraints on the side.

2) I see a lot of videos where the steps don't have side walls and the balls very politely stay on their step. This one works for me 50% of the time, they fall off a lot. What's up with that?

3) I had to give a 2 plate drop between steps, instead of what looks to be a 1plate drop, as the balls were at times happily rocking back and forth, but not actually along the steps, is this normal? (I may try the large 1x2 cheese slope with grille tonight to see how that works for me.)


(ps) First module, simple, but getting my feet wet on technic stuff.

Posted by on 24 August 2015 at 17:34.
Edited by on 24 August 2015 at 17:35.


Congrads for jumping into GBC.

For the Zig-Zag, make sure your opening is the correct size. Not sure what Akiyuki's module is like, but the video I just looked at appears to have a large opening with a window covering the top part, so it's not as large as it looks. (sorry, I'm not helpful, here)

For the step lift, my solution was to support both sides of the step. So there are two "drives", going the same direction. They don't have to go the same direction, but if you make them go opposite directions, the gears/drive will be 1/2 tooth out of sync, so the steps will not be completely flat.

You can almost see one side of the drive in this video: https://youtu.be/3BQ7aqCMzBA?t=553

Your Archimedes Screw looks very good.


Posted by on 25 August 2015 at 20:18.

Thanks for the suggestions Steve. I tried last night using two drives, but it still seemed sloppy for my taste. Perhaps I built it wrong, or shouldn't have gone with double acting. Pictures: (1)(2)

With the side support, I did take a few pictures, but have torn it all apart. 1, 2, 3.

Here's where the step feeder was on Monday night: https://www.youtube.com/watch?v=U6KX3BO-cYg I've since tweaked the steps some and finished up the in-basket, it is still too high, so for the moment, I've resigned myself to having my Archimedes Screw be the module before, since it has no issue with a 12 high in-basket. No video, alas, my old motor is dying/dead and so I ordered up 3 PF M-motors last night. (And 2 of 8886 to use the train controller to power.)

Posted by on 26 August 2015 at 12:23.

Apparently I don't have privileges to edit my own reply? Pic 2 of two drives.

Pic 3 of side support.

Posted by on 26 August 2015 at 12:25.


Not sure if it's a result of design-in-progress, but I rather like the two different stages (one double acting, one not) I don't have an immediate suggestion on improvements to get the steps straight. ok, that's not true. I always have comments.

I'd like to start by saying this is a good module. Most people try to be too ambitious on their first module, instead of trying to make a simple, functional module.

A few overall suggestions 1) Put the Sliding rails (axles that attempt to keep stairs flat) farther apart. Go 10 or 12 instead of just 8 studs. 2) Use a single axle to connect joiners on the sliding rails. Instead of two 2L axles, use one 6L axle. Or longer if you follow step 1 3) Replace the sliding sub-step assembly with a 2x8 Technic plate. That may require making it 1 stud narrower, if I've counted correctly. 4) To fix the height problem with the first step (in basket too high) consider putting the rails higher than the step, instead of underneath. The first step doesn't have to match all the others.


ps I think after some number of posts, you will be allowed to edit your own post.

Posted by on 28 August 2015 at 17:08.

Posted by on 2015-08-26 at 12:23:01.

Anonymous posters have limited privileges. For full privileges, create an account and make a couple non-forum edits.

The forum does have issues. If anyone has time to work on it, please jump in.

Posted by ALittleSlow (administrator) on 13 February 2018 at 02:13.

I just deleted someone's reply by accident when trying to delete spam! As I said, the forum has issues. One of them being the reply, edit, and delete buttons are associated with the wrong message!

Posted by ALittleSlow (administrator) on 13 February 2018 at 02:18.

Ah, that might explain why I've never been able to successfully edit my own messages!

Posted by Captainowie (administrator) on 13 February 2018 at 06:03.

I just built the zig-zag lift and having the same issues. I am using part #4864 and balls are not feeding smoothly. When they are moving up, they do sometimes double up and I'm having lots of jamming at the top. Any suggestions? I went off the parts list and building instructions from planet gbc...

Posted by Tlehrmann on 10 June 2018 at 02:54.

I've never built that module, but it looks like it might be sensitive to timing. Does it get any better when you slow it down?

Posted by ALittleSlow (administrator) on 2 July 2018 at 12:09.

Jams no matter how slow. Even moving it by hand.

Posted by Tlehrmann on 28 July 2018 at 12:06.

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