Intro: Forged Shelf Brackets
This Instructable will walk you through forging industrial style shelf brackets. I have this theory that if blacksmiths of a bygone era had access to abrasive chopsaws and MIG welders, they would have used them. So while I'm using some equipment that is nearly 100 years old, this isn't exactly a lesson in traditional techniques.
Feel free to comment, I like to talk about my projects.
Tools and materials shown here
- Center punch
- Metal marking pencil ( Welder pencil on Zoro )
- Soapstone holder ( Soapstone holder on Zoro )
- Metal framing square
- Tape measure
- Little Giant 50lb power hammer
- DeWalt abrasive cutoff saw
- Craftsman floor standing drill press
- HF Mig welder
- Antique Vulcan anvil
- Craftsman mechanics hammer
- Rounding hammer ( Hammer on Kayne & Sons )
- Propane forge
- Parker vise
- Locking C-clamp ( Clamp on Zoro )
- 1-1/4" x 1/4" flat steel
- 1" x 3/8" flat steel
- 1/4" rivets
- Chemical patina
Step 1: Cut the Material to Length
This write-up shows making a batch of 12 brackets, so there is a good bit of cutting involved. My metal comes from a local metal distributor who receives the stock in 16' pieces. 16' is too long to fit in my truck, it can't be stored on end in my shop, and it won't fit under my fume hood, so I have the distributor cut all of stock into 7' lengths.
When it comes time to mark the work piece, soapstone in a soapstone holder works great when things don't have to be accurate. Mark at 14", cut, repeat for 12 pieces.
Statisticians talk about accuracy and precision. If you want to make a pair of brackets precise, but don't care about accuracy, cut them both at the same time. They might come out precisely 13-31/32", but will both be almost precisely the same. For artistic work, the balance and symmetry is more important than getting an accurate 14" cut.
What will become a riveted and curved piece is cut with the ends at a 45-degree alternate angles. For the 90-degree cuts, the clamp on the saw isn't even necessary. Just hold them in place, and slice. The rotation of the saw will push the work piece against the fence.
But cutting at a 45-degree angle is a different story. At 45-degrees, the cutoff wheel wants to pull the work piece forward, and will wreck the angle on your cut. The little clamp built into the saw is nice, but because the screw is pushing at an angle, it doesn't hold very tight. For making 24 cuts like this, it is easier to use locking C-clamp to squeeze the clamp against the fence.
Do you like the action shot with the sparks flying? That was tricky. I had to cut with my left hand, and take photos with the other hand, until I managed to hold the camera still enough to get a cool effect.
Step 2: Hammer Flats on the Ends
This is pretty straightforward, and the most fun part of the project. I'm using a 50 lb Little Giant power hammer. It was built in the 1930s, and spent its life in Nebraska. It is a massive cast iron beast that is a pleasure to operate. I really like this tool.
Fire up the forge, heat the metal until it is all orange and glowing, then hammer flats on the ends of the 14" steel pieces.
This will stretch the metal, so it is important to get each piece to roughly the same heat, and hit it the same number of times. The heat is judged by the color. To hit the same number of times, I like to align the end of the bar with the far edge of the bottom anvil, then pull it out. As it is pulled back, keep a consistent distance between each hammer blow. I find it easier to keep a consistent distance than to count hammer whacks.
Step 3: Clean the Burrs on the Metal
Why a whole step dedicated to a single operation? I once snagged my thumb on a metal burr, and wound up in the emergency room getting seven stitches. And I've got a couple of similar cuts since then. At some point I learned my lesson, and get the jagged little razor blades out of my shop as soon as the saw makes them.
Smooth the edges with a belt grinder, belt sander, a sanding disk in a drill, a good file, your Dremel tool, or whatever you can come up with.
Step 4: Drill Rivet and Mounting Holes
For making bulk layout marks, I like to use the framing square. Use it to align the side and the ends for a stack of material, then use it to mark all of the pieces at once.
For finding the center for rivets, use dividers or a compass to mark from each side, then center punch between the marks. No measuring required, just get it close.
After coming out of the forge, there is a good bit of scale on the brackets. The divider scratches were too hard to see, so I used a Sharpie like layout fluid. The ink will burn off in the forge, or alcohol works for do-overs.
For marking the mounting holes, they need to be close to the edge so you can get a screwdriver around the curved piece to install the screws. By locking your hand onto the pencil, you can transfer marks onto all of the work pieces, without having to measure every time. Grab tightly, and slide the end of your finger down the edge of the work piece while marking. I would estimate the marks are within 1/32" of each other.
Step 5: Bend and Add Rivets
Matching marks are scratched on the drilled work piece to indicate where the vise jaws should be clamped. The bend will be centered slightly above the mark, so make the mark slightly below center. Get the first piece bent how you like it, then quench it and use it as a reference for bending all of the other pieces. To prevent accumulated error, don't match each piece to the previous piece; instead match each one to the first piece. And when I say match, I mean hold the cold reference piece against the hot work in the vise, then bend to match.
The rivets are pure ornamentation, they don't hold anything. Tap the rivets in place. The 1/4" holes drilled earlier will distort near the curve, so drill them back out if the rivets don't fit. MIG weld from the back side, then grind the welds to a consistent height.
Step 6: Bend the Brackets and Weld in the Curved Piece
After hammering the ends, the 14" work pieces have stretched to 15" or 16". Mark all of the pieces where you want the vise jaws to press, heat them in the forge, and clamp them in the vise. Work fast: bend the piece to about 90-degrees with it clamped vertically in the vise. Then before it looses its heat, clamp horizontally and adjust it square with a steel framing square. The piece that was hammered over will likely have some curve to it, so use the vise to pull it flat. The framing square can heat up when pressed against the metal, so be careful.
Clamp the curved piece into the bracket with the locking C-clamps and weld through the 3/8" hole in the bracket. The holes are drilled in the brackets after the metal is bent. It is a little tricky getting the bent bracket in the drill press, but it helps make sure the weld is completely hidden.
After welding, the 45-degree edge may not sit flush, so heat the weld up in the forge and lightly pein it (hit with the pointed end of a ball pien hammer) to close the gap. Don't whack it too hard, or the weld will break.
Step 7: Finishing
At this point, the metal work is finished.
The brackets are put in a vibrating tumbler with ceramic media to clean the scale. If you don't leave your metal in the forge too long, and carefully brush the scale with every heat, you might not need to do this. But I don't worry about it the scale and red oxide, and let the tumbler do the work.
A chemical patina is used to darken the steel. These patinas are very acidic, so be sure to use an acid vapor respirator and a face shield. Seriously, get the right respirator or else use a hot beeswax finish. Once I didn't think I needed a respirator, then woke up that night with blood dripping out of my nose.
The final finish is a dip in Permalac lacquer. This is an expensive finish, but it resists water and UV, and since I sell these, I want something that holds up. As a test, I dipped a hook, and left it in a shower for a month. This finish protects the steel really well.
I doubt I will make many more of these. You can see from this write-up, they take forever to build, and it pulls my hourly rate down lower than I want. But I still have some for sale: