A 3D Printed Automotive Switch Panel - Part 2




Introduction: A 3D Printed Automotive Switch Panel - Part 2

About: I'm a Mechanical Engineer turned IT Professional and Author. I came into the Information Technology world because someone challenged me to. But at heart, I'm still a grease monkey with no desire to lose touch …

A few days ago I printed out an Automotive Switch Panel on my 3D Printer.

This project was published in another instructable titled A 3D printed Automotive Switch Panel.

With the switch panel ready, it was time to put it to good use.

In this instructable, I will be replacing the existing switch box on my 1923 Model T street rod with this new and improved switch panel.

Step 1: Things You Will Need

  1. Masking Tape
  2. A Pick
  3. At least 3 screws for fastening the switch plate to the body- depends on the size of screws you pick out
  4. Atleast 2 bolts and nuts to mount the assembled switch panel on the steering column
  5. A Drill
  6. A Drill bit or two - based on the screws picked out
  7. A pair of clamps with padded jaws - hard metal would risk cracking or breaking the parts because they're printed out of PLA
  8. A marker pen
  9. Other tools as needed such as Allen wrenches, bench vice, files etc.


  • There is no specification on the size or length of the screws to be used
  • I picked 3 of a kind that would proportionately fit as part of the application
  • The drill bits were picked after deciding on the screws and mounting bolts

Step 2: Locating the Switch Panel Holes

I started off by locating the points where the Switch panel would be attached to the body.

A few tabs were designed as part of the switch panel -the switch panel would be fastened to the body by using these tabs

Obviously, it wasn't required that all tab s be used for this purpose

Therefore, I decided to use just 3 of the 5 tabs

To begin with, I striped the body with masking tape at the spots corresponding to the locations of the tabs that I decided to use

Using a pick, I made indentations at the center of each tab as a starting point for pre-drilling the holes for the fastener screws

Step 3: Drilling the Fastening Holes

Before actually drilling the first pilot hole, the jaws of the clamps were covered with masking tape to protect the parts from the heavily used and weathered clamps.

With the parts clamped, the smallest pilot hole was drilled at all three fastening locations

Initial attempts to thread the fastener screws into these holes using a screw driver weren't successful because they were too small and the screws had to bite through too much of PLA material.

Using a power tool was not an option because I should be able to fasten and/or undo these screws with a screw driver.

Therefore, it was time to enlarge the holes so that the screws could be fastened using a regular screw driver and not something heavy like a power tool.

Step 4: Threading in the Fasteners

Using a slightly larger drill bit, the three holes were enlarged a little.

This time, just by using a mini screw driver, I was able to thread each of the three screws through the body and right through the mounting tabs of the switch panel.

As expected, the screws don't look too large or ungainly when seen as part of the entire assembly

Once all of the entire assembly is done, I should probably replace these screws with good looking chromed or stainless steel ones.

Alternately, I could paint them all Black to match the color of the body and make them near invisible!


If you observe the switch panel carefully, you'll see that the tabs on the circular side of the panel are not flat

In fact, they are curved and the outer radius of these tabs match the inner radius of the body

When the screw is driven through, the curved tabs will be pulled in properly against the body without running the risk of cracking or breaking the tabs

The last visual shows the comparison between the two design scenarios to better articulate this point

Step 5: Mounting Holes for the Body

The next step in the process was to locate and drill the mounting holes in the body. These holes would be used to mount this entire assembly on to the steering column.

Before proceeding, I decide to mask off the entire white portion of the assembly with masking tape to avoid greasy finger print smudges.

In addition, a couple more strips of masking tape were striped on the body where the mounting holes would be marked out and drilled.

Selecting a suitable mounting method:

During the course of designing the switch panel, I printed out a few prototypes of several different mounting brackets.

But as mentioned in my earlier IBLE, I decided to use the existing horn button to mount the switch panel to the steering column

The spring clamp that came with the button would serve as a template to locate the mounting holes- there was simply no need to reinvent the wheel and wrestle with newly designed mounting clamps.

However, I had to play around with a few options on how the horn button and the switch panel would be mounted as a single unit, and the option I finally decided to go with was to invert the mounting bolts.

Meaning, the bolts would be mounted to the body inside out and therefore providing the advantage of having their extra length to mount the horn (for now) and some other accessory in the near future!

Locating and Drilling the mounting holes:

  1. There was no way of getting around a vice this time!
  2. Using the spring clamp, the first holes were drilled out
  3. These holes were then enlarged until the bolts could slide in and out
  4. The larger holes caused the PLA to melt and leave a residue that had to be filed away
  5. With the holes drilled out , the masking tape strips applied earlier were removed

Step 6: The Minor Adjustments

For some reason, the drill may have drifted a tiny bit, but nevertheless caused some minor hiccups.

One hole was drilled closer to the center than the other

As a result, one of the bolt heads caused a dysfunctional interference with the inner circular edge of the body

There was no way, the switch panel would mount without having a stress fracture!

The solution? The hole was filed away in small amounts (at the location marked with a white metal marker), just enough to drift the bolt head away from the center and sit flush against the inside edge of the body

Step 7: Off With the Old, and in With the New!

It was time for the disgusting old switch box to go!

The new switch panel body was mounted on to the steering column in place of the old box

The horn button was mounted on the bolts on the opposite side of the steering column and tightened down with nuts

With that, the next step was to transplant the switches and wiring into the new box!

This was actually a very simple process. All that was needed to be done was to pull each set of wires through the hole at the bottom of the body and then reconnect them back to the switches.

The switches were mounted in the three inner positions, leaving the outer two holes for mounting the Left/Right blinker lights (a future TODO, as I have to add extra lights and wiring).

Finally, the switch panel was assembled on the body to be held in place by the three fastening screws.

Step 8: Design Notes, Pros and Cons

Taking care not to destroy the switch panel, the three fasteners were threaded in to hold the switch panel in place on the body.

That's it! To date, this has been my largest, very practical and most successful 3D printing project!!

Just for the kicks, the fasteners were colored Black using a permanent marker - as seen from the pictures of the final assembly, they look blended in with the body.

Design Pros and Cons

The design section of my earlier IBLE started out with a few basic objectives. At the time, all of this was theoretical and I never expected that I would see this project to its end.

But now that I see it in action, I should summarize some of the pros and cons of this design


The circular design has served it's purpose - it wraps snugly around the steering column

My foot doesn't run into it like it did with the switch box - which means no unwarranted movements!

No more ugly wires sticking out from the underside of the assembly

The use of tabs to mount the switch panel makes it possible to simply back the screws out just enough to take off the top switch plate and in addition offer the following advantages:

  • Uses less material to print the body, as no additional mounting points for screws are needed
  • Shorter screws would be needed to mount the panel to the body
  • Horizontal screws mean more space inside the body for wires and switches and less stress on the switch panel face and the screws

In contrast, if the switch panel were to be held in place with screws driven through the top face, they would've come with the following demerits:

  • The body would need more material to print and longer screws would be needed to hold the panel in place
  • The screws would intrude into the space inside and cause problems when routing wires or moving switches around
  • The screws would clutter the face of the switch panel - not very appealing to the eye to see 3 screw alongside three switches
  • Finally, holding the switch panel down with face mounted screws would put more stress on the panel
  • Over-tightening the screws would risk stripping the threads inside the body!


  • The fasteners may be too small and frequently unscrewing them to remove the switch panel may cause the holes in the body to enlarge requiring the need for using larger screws
  • Using too long screws may lead to damaging the switches - not good!

Step 9: Next Steps

Time for a drive obviously! But a few things remain such as:

  1. Those mounting bolts are a bit too long - they will need to be replaced with shorter versions
  2. After a few days, I may have to dismount the assembly, and hit it with a coat of clear to give it an extra shine and also protect it from the elements
  3. I'm undecided on whether or not I should paint the switch panel Black to match the rest of the body
  4. Alternately, I could just print another one in Black, and without the Raft support (please see earlier IBLE)
  5. A couple of improvements I would add is to measure the locations of all the fasterners and bolts and incorporate them as part of the design
  6. With this enhancement, the holes will be printed out should I decide to reprint this part in the near future

Well, that's it! Thanks for reading my IBLE!

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    2 Discussions


    4 years ago

    Cool! Wish I had a 3D printer. #TheStruggleIsReal LOL ;)


    Reply 4 years ago

    very true! The struggle is indeed real, but rewarding as well!

    took me close to a year and half amidst other things to get my printer to this state!

    thanks for reading my ible.