Intro: Make Your Own Hairpin Legs for a Wooden Cookie Table
I visited Istanbul on Jan 2016 (hence the table name :)) and I brought in my suitcase a wooden cookie that I got for a few liras. Sadly, while I was still making the legs, it cracked, so I had to rearrange the structure, but it ended up looking cooler than before :) The cookie is around 40cm diameter and 4cm width.
For the leg structure I used Φ10mm x 1m steel rod and 4x40mm steel plate.
To make the bending jig I used:
- 2 hinges Φ18mm (this will form the curve of each leg)
- 30x20mm x 80cm long square steel tube
- 45x35mm x 10cm square steel tube
I used a lathe to just to practice and make easier the hinge assembly but you won't really need it. An angle grinder and a welder will do.
I will explain what I made but the video will probably help a lot
Step 1: Make the Bending Jig
I made a hole in the square tube so that once the hinge is inserted, the gap between the hinge and the edge will fit the 10mm steel rod. The hinge half was welded in place and the weld was rounded with a file to make sure it receives the steel rod with no interferences.
I added a backer plate in the aforementioned edge to support the rod while it's being bent. Eventually the leg curve will be tangent to this plate and the tube edge. You can add a couple more to make sure the rod will not move.
Now for the bending head. I simply drilled two holes 50mm apart to have some leverage and welded the hinge halves in place making sure they were inserted the same depth into the 35x45mm tube. One of the hinge halveswill as a free roller that can ride along the rod while it's being bent and reduce friction. I cut the female part of the hinge in half to get a thick steel tube and screwed a bolt onto the end of the male part to keep this roller in place. That's it! a couple of oil drops and it's good to go. Then I can just insert a big still bar to apply the necessary leverage
Additionally, to make sure it lasts more than 3 legs, I reinforced the tube with some steel plate in the bar contact points.
Step 2: Bending the Legs and Preparing the Plates
I secured the bending jig to the most stable bench I had. Then I just inserted the rod and started bending! It is a good idea to mark the center of the rod and add another mark to align it with the backer plate. This way all the legs are consistent. Regarding how much should they be bent - I was aiming for around 8cm gap between the ends. I added a reference to the jig (unfortunately I don't have a picture) but I was basically bending a little bit more until it felt right. The steel plates will have holes to receive the leg ends and the bent rod is basically a spring so it will adapt easily!
Once the rods were bent I prepared the three 16cm long steel plates, drilling holes spaced 8cm. I also drilled another 4mm holes to screw the plates to the tabletop. Better views in the next step!
Step 3: The Welding Jig
The legs should have an angle of around 7º, so I stacked wood scraps until the plate could rest at the desirable heigth to get that angle if the tip of the leg is resting over the table. To keep the plate vertical I added a couple of scraps and clamped the plates.
To make sure the leg is centered and all of them have the same lenght, I drilled a hole in the table and used what was left of the hinge as a dowel. This way I just had to insert the ends of the leg in the steel plate and push it inside until it reaches the dowel.
Then I first tacked the pieces in place in the jig and finished it freely once they were secured.
Step 4: Completing the Structure
I made a template of the cokie in the table so I could screw each leg and then weld them together. Initially it was going to be a hexagon but since the crack appeared, one side is left open. No stability issues though. Just added an angle cut to the plates and cut pieces to fill the gaps.
The distance between the leg plate and the edge of the tabletop should be set so the tip of the leg is aligned vertically with the tabletop edge or a bit inside.
Step 5: Finishing the Tabletop and Attaching the Structure
The cookie was in good conditions and pre-finished so I just scrapped some dirt and mold and oiled it (not in the video) After that it was just matter of screwing the structure onto the cookie with some predrills and regular screws. The metal structure should as well prevent the crack from spreading, but who knows, I'll let it be!