Knex Coin Sorter




Introduction: Knex Coin Sorter

About: On my page you'll find lots of different Knex projects, from ball machine lifts to useful items. I hope you enjoy!  _______________________ Current avatar: Target of my skeeball machine Past avatars: …

I didn't want to buy an expensive commercial coin sorter, so I decided to make this instead! It sorts dimes, pennies, nickels, and quarters into store-bought paper sleeves. It runs using a motor, and the sorting tray on top goes back and forth, sorting the coins according to their size.

Click here to see Knex Coin Sorter Version 2!

You don't have to use paper sleeves to store the coins; you can just have them fall into piles or into something else.

EDIT: This reached 5.00*, thanks to everyone who rated! :-)

Here is a video of the coin sorter in action!

So, if you like it and want to build it, then it's onto Step 1!

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Step 1: Parts List

Here's all the pieces you'll need to build the coin sorter:

Rods: 261
  • green- 87
  • white- 63
  • blue- 61
  • yellow- 38
  • red- 3
  • gray- 9

Connectors: 285
  • dark gray- 68
  • light gray- 10
  • red- 24
  • green- 6
  • yellow- 19
  • white- 19
  • orange- 63
  • blue- 14
  • purple- 62

  • silver spacer- 42
  • blue spacer- 55
  • Y-connector- 24
  • tan clip- 12
  • blue clip- 2
  • blue hinge- 1
  • black hinge- 9
  • motor- 1
  • small blue gear- 1
  • red gear- 1
And, get 4 paper sleeves for each coin if you want to use them.

Total: 694

If you have all these pieces, then let's get building! :-)

Step 2: The Base, Part 1

First off, build the base. This is Part 1, the center of the base. You'll make two sections for it, and then connect them together. Pictures 1-3 are the back section, and pictures 4-7 are the front section. After both sections are complete, put them together (pictures 8-11). There are descriptions for each picture below:

Pic. 1- Back section.
Pic. 2- Another view.
Pic. 3- Close-up of the blue spacers.
Pic. 4- Front section.
Pic. 5- Another view.
Pic. 6- The bottom of it.
Pic. 7- Don't forget the two Y-connectors!
Pic. 8- Get the two sections.
Pic. 9- Attach them together. The blue rod on the back section should slide into the white connector in the front section.
Pic. 10- Another view.
Pic. 11- Another view.

Step 3: The Base, Part 2

Now you'll make Part 2 of the Base. This is the short side, or the right of the base. Do not connect the two white rods coming from the yellow connector at the top (picture 3 shows a close-up). After you build it, connect it to the rest (pictures 5-7). Again, there are descriptions below.

Pic. 1- Build this.
Pic. 2- Another view.
Pic. 3- The part with the red connectors should be facing upwards.
Pic. 4- Remember those silver spacers.
Pic. 5- Get the rest of the base.
Pic. 6- Attach it to the right side.
Pic. 7- Another view.

Step 4: The Base, Part 3

This is the taller side of the base, or the left. First, build the front section, and then the back section. Then attach those sections and add them to the rest of the base.

Pic. 1- Front section.
Pic. 2- Another view.
Pic. 3- Back section.
Pic. 4- Don't forget to add that gear!
Pic. 5- Get the front and back sections you just made.
Pic. 6- Combine the front and back.
Pic. 7- Another view.
Pic. 8- Add it to the left side of the base.
Pic. 9- The entire base is now complete!

Step 5: The Motor

This is the motor part of the coin sorter. This step is very easy, so it shouldn't take you too long. First, build the motor attachment, and then connect it all to the left side of the base.

Pic. 1- Get the motor, and build the small bit. Make sure the motor has batteries installed!
Pic. 2- Get the base.
Pic. 3- Attach the motor. Make sure some of the yellow rod is sticking out.
Pic. 4- Attach the small bit. The yellow rod won't have any end connectors, so it should fit in nicely.
Pic. 5- Another view.

After that's done, it's on to the next step!

Step 6: The Mechanism

This part will make the sorting tray move up and down. First, make the crankshaft attachment. This will hold the crankshaft. After you attach that, make the crankshaft. Then attach the small support. There are a lot of pictures in this step, so read through the descriptions carefully.

Pic. 1- Build the crankshaft attachment.
Pic. 2- Another view.
Pic. 3- Right side.
Pic. 4- Another view.
Pic. 5- Left side.
Pic. 6- Get the rest (the base and motor section).
Pic. 7- Attach it to the back of the base.
Pic. 8- Another view.
Pic. 9- Build the crankshaft.
Pic. 10- Don't forget the spacers!
Pic. 11- The crank, and right side.
Pic. 12- Another view.
Pic. 13- Another view, with the hinge.
Pic. 14- The left side.
Pic. 15- Get the rest of the model.
Pic. 16- Attach the crankshaft the the back. Make sure the red connector and dark gray connectors on the crank part are like they are in the picture!
Pic. 17- Another view of the left.
Pic. 18- Close-up of the gears. Make sure that they mesh together. Also, there should be a green rod connected to the top of the white connector, like in picture 17.
Pic. 19- Another view of the right.
Pic. 20- Build this support.
Pic. 21- Attach it like so.

You have now completed the mechanism!

Step 7: The Sorting Tray, Part 1

Now you'll build the sorting tray, which sorts the coins. This is Part 1, which includes the tray, cover, and coin barriers. You'll build and attach those all in order.

Pic. 1- Build the tray. Make sure to remember all of the spacers!
Pic. 2- Another view.
Pic. 3- The left side.
Pic. 4- The center.
Pic. 5- The right side.
Pic. 6- Another view of the right (bottom).
Pic. 7- The bottom.
Pic. 8- Don't forget the three Y-connectors, which should be facing down.
Pic. 9- Set the tray aside, and build the cover. Make sure that the blue spacers stay on the end of the rods.
Pic. 10- The right.
Pic. 11- Another view.
Pic. 12- Another view.
Pic. 13- Get the tray and cover you just built.
Pic. 14- Attach them. It may be a bit difficult to snap the gray rod into the orange connectors, but make sure the tray doesn't fall apart.
Pic. 15- Another view. For now, keep the cover flipped outward.
Pic. 16- Build the barriers. Keep everything in order like I have it in this picture.
Pic. 17- Get the rest of the sorting tray.
Pic. 18- Attach the larger part of the barriers. The blue rods should fit through the tray, and the Y-connectors should be in the holes of the yellow/orange connectors.
Pic. 19- Attach the 3 orange connectors to the bottoms of the blue rods.
Pic. 20- Attach the blue rods with the spacers on them. Make sure the silver spacers are on top of the yellow/orange connectors!
Pic. 21- All three barriers complete. The one to the far left should not have a silver spacer on one of the blue rods, like it is in the picture.

Step 8: The Sorting Tray, Part 2

This is Part 2 of the sorting tray. It includes the end piece and the coin insert. First, you'll build the end piece, attach it to the tray, then the coin insert. After the entire sorting tray is complete, you'll attach it to the model.

Pic. 1- Build the end piece.
Pic. 2- Another view.
Pic. 3- Another view.
Pic. 4- The axle. This will connect the sorting tray to the left side.
Pic. 5- Another view.
Pic. 6- Get the rest of the sorting tray.
Pic. 7- Before you attach the end piece, flip the cover over and attach it. It connects on the right side.
Pic. 8- Another view. The yellow connector connects to the gray rod below, and the orange connector connects to the top center gray rod.
Pic. 9- Attach the end piece. Don't forget the white rod! It doesn't attach anywhere; it just sits in the hole of the dark gray connector.
Pic. 10- Another view (bottom). Remember the 2 blue spacers on the green rod, and make sure the other blue spacers on the ends of the gray rods didn't fall off.
Pic. 11- Another view (top).
Pic. 12- Build the coin insert.
Pic. 13- Another view, showing the spacers.
Pic. 14- Another view (bottom).
Pic. 15- Get the rest of the sorting tray.
Pic. 16- Attach the coin insert to the left of the tray. There is only one connection.
Pic. 17- Close-up showing the connection, which is an orange connector and gray rod. it should be in between two blue spacers.
Pic. 18- Close-up showing the position of the white rod. The tip near the black hinge should be in the red connector. Also, the white rod should have a snug fit, so tilt the dark gray connector (near the green connector) towards the light gray connector in the back.
Pic. 19- The entire sorting tray is now complete! Get the rest of the model.
Pic. 20- Attach the sorting tray. It should swivel easily before you attach the crankshaft.
Pic. 21- Close-up of the left side.
Pic. 22- Close-up of the left side. The tip of the gray rod slides into the hole of the red connector.
Pic. 23- Close-up of the crankshaft's connection. Notice the direction that the hinge is facing; yours should be the same. The hinge should have a slight bend to it.

Now that you are done with the sorting tray, look at the dime and penny slots (the two slots near the left). The penny slot should be just a bit bigger than the dime slot. The penny should not be able to make it through the dime slot.

Step 9: The Coin Slide

This is the thing that the coins slide on to get to the containers. First you'll build it, and then attach it to the rest.

Pic. 1- Build the coin slide.
Pic. 2- Another view.
Pic. 3- Another view. Don't forget the three Y-connectors, which are attached to the gray rod.
Pic. 4- Another view.
Pic. 5- Close-up of the right.
Pic. 6- Get the rest of the coin sorter.
Pic. 7- Attach it to the front.
Pic. 8- This shows the connections. Make sure to connect the two dark gray connectors to the Y-connectors.

Step 10: The Coin Holders

These are four containers, which hold the coins. If you don't want to sort your coins into paper sleeves, then skip this step and go to Step 12.

First, you'll build the coin holders, and then attach it to the model.

Pic. 1- Build the coin holders. Pay special attention to the spacers on the gray rod, and the directions the black hinges are facing.
Pic. 2- Another view.
Pic. 3- Close-up of the nickel and quarter holders.
Pic. 4- Close-up of the dime and penny holders.
Pic. 5- Get the rest of the model.
Pic. 6- Attach it to the bottom.
Pic. 7- Another view.

You are almost done with the coin sorter!

Step 11: Add the Paper Sleeves

Get the paper sleeves, and put them in their appropriate container.

Pic. 1- Get the paper sleeves.
Pic. 2- Put them in their appropriate container. You should add one coin into the bottom of each, so the coins that follow will land flat. Then, look at the tops of your paper sleeves. If there is a "bad side", or a side that looks messy around the top, put that side in the back. This helps the coins to slide into the sleeves better.
Pic. 3- Attach the tops of the containers. The quarter's holder attaches separately from all the others.

Step 12: You Are Done!

Congratulations, you are now finished with the coin sorter!

Push the motor's switch to the right, load some coins into the coin insert, and watch it sort! It works better if you load them in one by one, like I did in my video.

If you built it, send me a picture and I'll put it on this step. :-)

Please comment, rate, and Subscribe!


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    Question 1 year ago

    can we sub the black hinges with purple connecters i am going to make if yes


    5 years ago



    Reply 5 years ago

    Haven't seen that one before, thanks!


    Reply 5 years ago

    No worries...haven't seen what before? The word Coinsome? I just made it up on the spur of the moment b4 i was gonna write Awesome!!! :D

    can you make this out of the small pieces for k'nex's because i don't have a lot of the big pieces


    8 years ago

    And another

    13 6:27 PM.jpg

    8 years ago

    Still upgrading it

    13 6:28 PM.jpg

    8 years ago

    This is really cool I am going to try and build this but I will have to substitute parts because I do not have enough dark gray pieces


    8 years ago

    I think I am going to cover the machine with full moons and make a slot where u put the coins in I will post it


    8 years ago

    If it work I am going to enters it in my town fair


    9 years ago on Introduction

    Still don't know how to reply correctly. =/ Still, I am very, VERY, grateful for this, I can now order my own Christmas present. ^_^


    9 years ago on Introduction

    -_- I posted my reply but it didn't show up and now I have to re-post. So... pictures of all the connectors excluding green, and the Y-connector. If you can, of course. I will be very grateful for this because i first saw this almost half a year ago and I'm only just getting around to following through with it. =/
    By the way...
    this was my second post attempt, copied and pasted because it would not let me reply. it kept saying "please type the 2 words on the page, but it would not do anything when i tried.