I have a line of Inserter assemblers, and I need to feed them cogs, circuits, and iron plates. I decided to mix the cogs and circuits on one side of the belt, and have the iron plates on the other side:

Setup example

This works well providing there aren't any shortages up the line. If one side of the cogs develops a shortage (so there are only cogs on one side of the belt feeding into the "combining splitter"), then the ratio of circuits:cogs gets messed up, and the ingredient loop in the bottom right gets plugged up with circuits. To get the system going again, I need to manually pick up the ingredients plugging it up, and let it continue on:

enter image description here

I tried using a filter arm to pick out circuits, but they're too fast, and end up taking way too many off, then I have the problem of cogs plugging everything up.

How can I reliably mix 3 to 4 ingredients on a single belt, and maintain the correct ratio (one cog per circuit in this case), even during shortages?

  • 1
    I'm about to got to bed, so I won't type up a full answer, but look into braiding your underground belts instead of trying to get everything on a single one. Or just run a second belt next to the first and use long inserters.
    – Fambida
    Commented Nov 19, 2016 at 17:44
  • @Fambida Hmm, I've never heard of "braiding" belts. I'll have to look that up. Thanks for the tip. Commented Nov 19, 2016 at 18:36
  • 1
    Yeah, mixing items in a lane without backups is really, really hard. You basically need signal circuitry for it to be reliable. Long inserters are much, much easier.
    – Paul Z
    Commented Nov 19, 2016 at 18:55
  • I have around 30 hours of play, and have never used long inserters. Maybe this is a good use case to try them out. Thanks guys. Commented Nov 19, 2016 at 18:57
  • 1
    puu.sh/9MZgq/ddfaac4791.jpg Here's a pic of belt braiding
    – Fambida
    Commented Nov 20, 2016 at 3:49

2 Answers 2


I took @Fambida and @Paul Z's suggestion to use long inserters, and came up with this:

enter image description here

Should be jam-proof.

  • +1 This is the usual solution. Note that if you run the circuits on the left you can get away without any underground belts Commented Nov 19, 2016 at 20:15
  • @BlueRaja-DannyPflughoeft I decided to pair circuits and cogs since they're both more likely to run out than iron is. In retrospect I'm not sure how sound that logic is though. Are there any "rules" for what should be paired on a belt, besides coal/ore? Commented Nov 19, 2016 at 21:55
  • 4
    Pair up stuff you use less of, so you can use slower less expensive belts.
    – Fambida
    Commented Nov 20, 2016 at 3:44

Consider making the cogs from iron where they are needed and inserting them directly from one assembler to another.

This way you only need 2 items on the belt, and you completely avoid the difficult issue of feeding your belt with the correct ratios of the 3 items.

  • I thought I'd come back and mention that this does end up being the best option in some cases. Shipping massive amounts of cogs and wire everywhere just leads to shortages and messy belts. In my late game factories, I made the cogs and wire where they're needed, since I'll usually have access to steel and copper anyways to make them. Commented Sep 5, 2017 at 18:04

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