Metal Bridge Bookends

For the past few months I've been having way too much fun in the Welding Certification Program at my local community college, CCAC. I was lucky enough to start school when my campus was purchasing, installing and training staff for a new Swift Cuts CNC Plasma Cutter. To say I was excited is a complete understatement!

I've worked with many different types of CNC in the past, and one of my favorite creations to date is a set of wooden bridge bookends I milled out on a CNC table router. I think the only thing that could possibly make them better would be a bit more weight, for heavier books. So, when my teacher gave me free rein of some donated 3/8" thick steel, I set out to redesign and remake a beefier set of bookends for myself.

-I've provided the DXFs that I used for this project. You'll need two of the "bridge wall" shapes and one of everything else.

-CNC Plasma Cutter

-Steel. I used 3/8" because it was free.

-Fusion 360 would be helpful for changing slot sizes if you aren't using the same thickness material.

-A welder- I used MIG for this.

-All the safety equipment! Hood, safety glasses, leathers, gloves, ear protection- the works. Protect yourself!

-Angle grinder with grinding disc.

-Paint or clearcoat, welder's choice.

-Painter's tape and Exacto knife if doing more than one color (for masking).

-Felt (I used by-the-yard purchased from Joanne's), scissors and E6000 glue.

-Bravery.

As I said in the intro, I've made a similar bookend in wood, but needed to do some modifications to make the project work with steel. I'd just learned about slot welds (a way to join the surface of a piece of material to another piece through an elongated hole) in my blueprint class so I wanted to be able to use this in my assembly processes.

I started my redesign by using a vector drawing program (Adobe Illustrator) to modify my preexisting bridge shapes to add slots and tabs that would fit together. Theoretically all these 2d shapes should line up but it can be hard to get a good idea of spacing and ratios when everything is on the same plane.

Cue Fusion 360! I exported my shapes as DXFs and pulled them into Fusion. This allowed me to extrude everything to the thickness of my material and fit my pieces together. This made me realize that I needed to shorten my tabs so when welding into my slots I had some extra room for my filler metal. Fusion also allowed me to change the color of my project easily, thus helping me settle on a good old fashion Pittsburgh color scheme.

My 3d mock-up gave me the confidence I needed to cut my shapes and throw some sparks. Unfortunately, plasma does not give you the cleanest cut, especially with material this thick, so there was a lot of clean up.

The machine cut at a slight angle, and, in hindsight, I wish I'd done a slot test (cut a single slot and tab to make sure they fit together) because I would have saved myself a lot of time if I'd made my slots a bit bigger. As it was, every tab needed material removed on all sides to make them fit. I hadn't taken this into a consideration because the CNC router table I used always cut straight lines!

I also took the time to grind the rust off all the surfaces so I'd have better welds and better paint adhesion.

So. Much. Grinding.

After what felt like a lifetime of grinding, all the pieces fit together! I did learn another lesson in fitting-

I thought I was so clever to tab my bridge bottom (the "road") into slots cut in my bridge sides... but I slotted them at the bottom of my shapes. So (Duh!) I had to fight gravity to get the road to stay put while I welded it into place! If I ever cut another set of these I'm definitely changing it so the slot is set on top of the bridge line so it will hold the road part up for me.

I used the MIG welding process to fill my slots, adhering my tabs in place. Finally, a smidge more grinding to make sure everything was flush, smooth, and to take off any sharp corners.

So, I learning yet another lesson in painting- lots of angles and tight spaces are hard. I ended up painting the "L" of the bookends black without worrying about over spray. After the 3-4 coats of black dried I spent a good deal of time masking off everything that wasn't the bridge so I could finish up with yellow.

While masking I had a lot of time to think about how to make a redo of the project easier for Future Me- I would want to weld the bridge together and paint it as one piece and paint the two, unattached, "L" pieces separately. Then I could assemble all the parts together and tack weld the 90 degree angle where the "L" meets. This means there would be no slot welds- the tabs would just be pressure fit. Theoretically, because tack welds are so small and produce less heat, I would only need minimal paint touch-ups on the base after assembly is done.

The other option would be to not paint it at all. Some day I might try turning the steel blue in the oven like in this Instructable on how to color steel at home.

The last step, to make them book and bookshelf safe (I didn't want to scratch anything with the metal!). I ended up using some E6000 to glue felt onto the bottom and side of the bookends.

Well this certainly turned into a labor of love and I definitely learned a lot. There's a bunch I would do differently next time, but these bookends will absolutely have a place of honor in my home!

Thanks for coming along on this creative adventure with me!