Assembly Instuctions Version 1.5

Please note these instructions are for an older design case that is no longer in production.  If you have recently purchased one of our machines please use the assembly instructions located here:

Version 1.5 Mechanical/Case Assembly Instructions For the Ultimate Useless Machine

Note:  we’ve updated the motor-mount bracket and the new assembly instructions are here.

If you purchased a fully soldered Machine follow the assembly instruction on this page.
If you purchased a KIT proceed to the Soldering Instructions first!
Step 1:
Remove the protective film covering the acrylic pieces. The film protects the pieces from getting scratched during shipping.

Click to Enlarge

Step 2:
Notice that the motor has a shaft on two sides. One side of the motor has a small bump by the motor shafts. You can see the bump in the photo in the following step.

Note:  We’ve switched to a new motor that only has one shaft. 

Use a #1 Phillips screwdriver to attach the motor, with the bump-side towards the acrylic motor-mount bracket, using the two longest screws.

Tip: Be careful that the motor wires do not become pinched between the motor and the acrylic bracket, causing a finger alignment problem later.

Step 3:

On the other side of the bracket, attach the micro-switch using two of the smaller screws.

Make sure you install the micro-switch so the bump on the micro-switch lever is at the top, as show in the photo to the right.

Step 4:
Attach the finger to the cam disc using two small screws.


Make sure the bump on the cam is orientated, as shown in the photo, so that the bump can touch the micro-switch when assembled.



Step 5:
Mount the finger and cam assembly to the motor shaft using the last small screw.

You may need to depress the lever on the micro-switch in order to clear the bump on the cam.

Step 6.
Understand how the mechanism works:

When the toggle is pointing to the left (the OFF position), then the green LED is lit and the motor turns clockwise  until the micro-switch is activated by the cam, cutting off power to the machine.

When you switch the toggle to the right (the ON position), then the micro-switch is bypassed, the red LED lights up, and the motor turns counterclockwise.


The arrow in the picture indicates where the bump on the cam is depressing the micro-switch lever.

When the toggle is in the OFF position and the micro-switch is depressed, then the machine should be powered off completely; there should be no power, no lights, and no motor movement.

Step 7.
Test your assembled mechanism:

With the toggle switch in the OFF position, put two AA batteries in the holder. The finger should turn clock-wise until the cam touches the micro-switch. The micro-switch is wired so that when pressed, the switch is open (or off), opposite from way most push buttons work. The green LED should then turn off.

Flip the toggle briefly to the ON position, and then back to the OFF position.

Warning: Be careful as the machine is not fully assembled so, if the toggle is left in the ON position too long, the motor will keep turning counterclockwise until the finger hits the micro-switch in the other direction.

You will want to flip the toggle back to the OFF position quickly.

If the motor turns in the wrong direction, then you have either installed the motor backwards or the batteries are in backwards.

Remove the batteries before proceeding to the next step.

Step 8:
Place a nut it the T-Slot on the motor bracket, as indicated by the arrow in the photo.

Tip: You can use a small piece of tape to hold the nut temporarily in place.

Carefully place the top cover plate on the tabs on the top of the motor mount bracket.

Step 9:
Carefully insert a bolt into the hole on the top plate. Thread the bolt into the nut and tighten it.

Notice: Two rectangles were laser-etched into the top plate on the other side of the center hole. Do not try to remove or punch out these rectangles as they are cosmetic and meant to balance the appearance of the real tabs of the motor mount bracket.

Drop a bolt into the hole between the rectangles and secure it from beneath with a nut.

Note: The protective blue film on the finger in these two photos is only to make the finger easier to see in the photo. You should have removed the protective film from all your acrylic pieces in the first step for assembly.

Step 10:
Remove the top hex nut on the toggle-switch.

Insert the toggle switch into the center hole of the top plate with the LED’s facing the finger.

Place the top hex nut back onto the toggle switch and carefully thread the hex nut on.  Tighten the hex nut with a 5-16″ socket or pliers.

Warning: Be careful not to scratch the acrylic while tightening the nuts.

You can insert batteries and fully test the mechanism. You should now have working innards for the Ultimate Useless Machine.

Remove batteries before proceeding to the next step.

Case Assembly

Step 11:
Start assembling the case:

Attach the lid as shown in the photo.  If you prefer having a blank ‘mystery’ box without “The Ultimate Useless Machine” text showing, then flip the top plate over and assemble the plate with the writing down.
Note: Pay attention to the orientation of the hinge plate. If you install the hinge with the wrong side facing out, you will have trouble fitting the lid into the case and the lid will not move freely.

Step 12:
Attach the sides of the case.

Note: Make sure the engraved lines on the front and side plates face out.




Step 13:
Leave out the final two nuts and bolts on the last side plate, and leave the other nuts loose in the plate, until you can slip the hinged end plate into the pivot holes on the side plates.

Then press the side plate into position and install the last two nuts and bolts.

Tighten the other nuts and bolts.

Step 14:
To keep the battery holder from moving around in the case, cut the velcro strip in two and apply the hooks side of the velcro to the bottom of battery holder.

Stick the fuzzy sides of the velcro to the corresponding locations inside the case.  Position the battery holder away from the acrylic finger, along the right side.


Step 15:
Lower the Toggle Plate Assembly into position on the top of the case and bolt it in place.



Step 16:
Stick the rubber feet onto the bottom of the machine. You are done!

Check for loosening of any nuts, including the one securing the toggle-switch.

To clean the acrylic case use a soft cloth and soapy water. DO NOT USE PAPER TOWELS on the acrylic case, it will leave small scratches!

35 thoughts on “Assembly Instuctions Version 1.5

  1. Pingback: Assembly Instructions Up «

  2. Mark

    The finger overtraveled in the closed position so the green LED did not shut off. I bent the microswitch blade a small amount up and that solved the problem.

    A GREAT kit that now sits on my desk for all to try and admire.


  3. Jean Nicolas

    Great kit ! Easy to assemble, fast shipping. Everything works according to plan.
    Thank you !

  4. Jim W

    Fun kit! (thanks for helping us newbie hobbyists with this solder-less version)

    The motor mount bracket in my kit doesn’t have the two tabs on the bottom that slot into the box base plate … is that a design change? or a bad bracket? doesn’t seem it will affect how it works, but just asking …


    1. Brett Post author


      That’s right made some changes to it, tabs weren’t needed, they just made it more difficult than need be to assemble.

      Also tightened up the placement of the micro-switch to prevent under and over-running of the finger when it comes to the home position.

    1. Brett Post author

      Thanks Gazza! I’m surprised my shipping manager didn’t pop all the bubbles before shipping out your kit. She can’t help herself…

  5. matt

    hi there,

    just got my kit and was wondering if you guys can tell me the size of the box in cm? i will build one and would like to check the dimensions before I start.

    1. Brett Post author

      The acrylic case is about 13x9x6.5cm. We’re going to have more info/instructions for the parts only kits added soon. But it’s very basic, and with the included motor-mount you won’t have to mess around getting the finger to line up with the toggle.

  6. Jon

    Good morning, I just received my three ‘parts only’ kits and found that I have two resistors and two places on the board for resistors however the instructions only discuss one resistor. My guess is two are required for the two LED’s, correct?

    1. Brett Post author

      You were sent the new boards and yes, there are two resistors. Same value resistors so they can go in either spot. The new soldering instructions should be posted tonight.

  7. Bob B.

    I purchased two kits and built them both today. I built the first one per the instructions and on the second one I moved the LEDs to the top panel. I used 5mm fast flash LEDs and mounted them on the right top side next to the appropiate on/off engravings. I used chrome 5mm LED holders for mounting, looks very nice. These are very well designed kits. Thanks, Bob

  8. Matt K

    A great piece of kit, completely useless! 😀
    Great instructions, very easy to complete, thank you.

  9. Bob R.


    As usual, initiating squawk to the T/S department results in instant enlightenment. Please disregard previous request.

    Plywood mounting bits are figured out and attached beautifully and pre-mount tests work as described. Now working on the box.

    Thanks again for the great kit – and the fabulous idea!

    Best Regards,

    Bob R.

  10. David W

    Thanks, Frivolous Engineering. The whole kit was very professional, with well designed parts and clear instructions. My son and I had fun building this for a primary school project on machines.

  11. Dan

    One of the best quality kits I have ever assembled. It looks and works great! I found it easier on some of the T-slot nuts to first thread a nut onto a bolt a couple of threads onto one plate and then slide the connecting plate onto the nut.

    Thanks for making and selling such a fun device. By the way, the name of your company, Frivolous Engineering, is fantastic!

  12. WM

    Great kit. I too had a small problem with the microswitch. It was a little too close to the cam and never opened. By bending the “feeler” away from the cam, I got it too work. Otherwise, good job. This was my second useless machine. The first one used tape for the hinge and I never really liked it.

  13. Russell and Gabriel

    Well, while using our heat gun to attach the heat shrink to the micro switch wires, we… um… melted the switch. Be careful about too much heat (duh).
    A trip to Radio Shack for a replacement switch and a little imagination got us going once again.
    Note that the Radio Shack switch is quite a bit larger than the original but one hole lined up and we drilled a second for a proper fit. Great project!

  14. Scott

    One suggestion to everyone. When I built two of these, on the first one we didn’t notice the protective film on the black acrylic box pieces until it was assembled. So we just removed the “outer” layer. The box functions much more solid feeling and quieter. So, if you get a chance, leave the protective film on the “inside” sides of the box. It makes it more solid feeling, and makes it seem built better.

  15. Alan Lefkow

    The product went together in a few hours and works exactly as it should. I enjoy your products.
    Alan Lefkow

  16. Jason & josh

    Took about 2.5 hours of great bonding for me and my son.
    Works great!!
    Thanks guys!!

  17. Sabine Eisenhauer

    What an absolute great machine. I want to buy one for school. Is it possible to take it apart and reassemble the machine again? I want a lot of kids have the experience to “built” this machine machine and see it work.

    1. Brett Post author

      Thanks Sabine! You can dis-assemble the case and the mechanism and then re-assemble. But I wouldn’t recommend trying to take the electronics apart.

      I should mention we offer educational discounts for schools.

  18. Roger in Virginia Beach

    VERY pleased at the quality of this product. Concise build instructions and nice fit of all the plexiglass panels. Real entertainer for the grandsons.

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