Now that's proper engineering, that is 
If these could be made cheaply enough from stainless steel (mild steel will rust away in that location), it would be a worthy replacement. Instead of all that filling and hacksawing, laser cutting springs to mind. Do you still have all the templates to hand..?
Also how did you secure the nails you used to join the 3 pieces together, burred over the end with a drift or ballpeen hammer..?
On a random note, I wonder if there is a hi-temp heat resistant material that could be 3D printed for something like this..?
If these could be made cheaply enough from stainless steel (mild steel will rust away in that location), it would be a worthy replacement. Instead of all that filling and hacksawing, laser cutting springs to mind. Do you still have all the templates to hand..?
Also how did you secure the nails you used to join the 3 pieces together, burred over the end with a drift or ballpeen hammer..?
On a random note, I wonder if there is a hi-temp heat resistant material that could be 3D printed for something like this..?