3D Printed Pedal Steel - Part 2

Proof of concept proven and some insights into the challenge at hand.

Fair warning! The following is likely a little too “in it” for anyone casually following along. I don’t think the entire process will be like this, but I appreciate those of you reading and just saying “Well good for Ben”.

Imagining a pedal steel mechanism is well beyond my abilities. For years I have thought about ways of making them but there was always one major shortcoming of those that I imagined. Pedal steel mechanisms (properly referred to as the “changer”) need to be able to move in a controlled way in two different directions. Every mechanism I thought up probably would have worked as long as I was willing to concede my creation to only moving the notes in one direction.

Wildly confused? Worry not, it’s not you. It’s wildly confusing. Here is a relatively short video that demonstrates a lot of the complexity.

My initial designs were simply connecting a string to a wheel, and then somehow pulling something to rotate the wheel-thus tightening the string. While I still think there might be something to a wheel tightening (or slacking) a string to change the pitch, setting stops to make the pitch changes consistent was going to be seemingly impossible. Setting stops in two different directions and making sure it came to rest repeatedly on the same pitch was just right out.

As the woefully overused saying goes, “Good _____ borrow, great _____ steal.”

Time to take a look at someone else’s homework and google “Pedal Steel mechanism”. Boom… turns out there is useful information on the internet if you’re searching for weird enough stuff.

From PedalSteel.fr

This gif warped my reality. While I may pretend to be familiar with engineering concepts, I’m not. This gif of a single changer affected by two different (and opposing mechanisms) set it all into action for me. While I still can’t fully imagine what a working pedal steel changer like this would look like in flesh and steel, it was enough to take into Fusion 360 and start messing around with it.

The changer concept

If you read my last post, you might recognize this video:

While I’m sure there is a VERY good reason the changer illustrated on PedalSteel.fr had three pieces, I thought two could work. The above video shows the very basic mechanism I came up with.

I’m sure there are folks out there who could tell Fusion the tensions involved and calculate the weight of the springs you’d need and even how much the pitch would change for every millimeter of mechanism travel. I cannot. For people like me, a 3D printer makes the impossible possible. With a 3d printer, I can try things out, make a change in my CAD model, and in 15 minutes try out the next iteration. I’m able to make some pretty cool stuff these days and it’s ONLY because I can quickly iterate through ideas in real life.

Reality sets in

I’m not sure Buddy Emmons ever screwed a bunch of stuff to an old 2x4 when he was helping create the first Sho-Bud, but he probably did. The above video is the 3d printed version of the first video. A couple of things became obvious to me at this point. Friction is a jerk, and figuring out how to make the mechanism return to pitch was going to be difficult.

Don’t lose sight of the goals

While the goal of this project is/was to create a 3d printed steel changer, mission creep has set in. Mission creep is when the goalposts start being moved—usually by the maker—and suddenly the list of ‘needs’ has grown to make the finish line impossibly difficult to cross.

My initial goals for this project were as follows:

1. Make a (mostly) working pedal steel of at least 6 strings.

2. Be able to play most of the chords commonly found in music I enjoy playing.

3. Be able to be duplicated by a kid with a will, a 3d printer, and a lot of tenacity.

To that list, the following was added.

The parts should be 2D and (if desired or) needed, able to be cut out on a laser cutter or water jet out of sheet steel.

While this added complication affects some of the engineering, it helps keep the parts simple, and in turn, the manufacturing will (or should) remain relatively simple. I (or you) could easily send files to a place like SendCutSend and in a week have metal parts in hand.

Proof of concept

After a couple of days of tinkering and maybe a dozen or so tweaks to the CAD or the 3D printed prototype I got here:

As you’ll see (or hear) the pitch addition of a second string helped get everything back to where it needs to be to get the mechanism to return the initial pitch. While I would love to have everything 3D printed, that was never a reality. There will always need to be metal hardware. Springs are obvious, and I’m using 3/16-in. metal dowels throughout the build because I have them and they’re just so damn useful. The rotation of a precisely printed hole brought too much friction. Once the hole was large enough to diminish the friction, there was too much slop in the mechanism to function properly. I pulled out some bronze bearings, reprinted the parts to work with them, and boom… a mostly working mechanism.

Refinement phase 1

The next day, the focus turned to figuring out how to downsize everything so the entire mechanism could fit into a 3/8-inch wide space. This is just one string worth of mechanics, and a playable instrument will have anywhere from 6-10 (or even 12) strings side by side. Those strings need to be a playable distance apart.

I added a few connectors to keep the springs off each other and made some linkages out of an old brass rod and a length of cable recycled from fixing Katies loom earlier in the day.

At this point, I need to start figuring out how more of these will come together and what a playable instrument will require me to make. I have a call into a steel guitar player much smarter than I am. Hopefully, he’ll be able to fill in some blanks that still have me scratching my head. When I was working in Nashville, I would have been able to wait a day or two until I saw a steel player and could measure this or that. The reality in Connecticut is NOT the same.

Nevertheless, I’m hopeful for this project and I’m enjoying documenting the processes.