To complete my restoration of TC2628 I still need a few small items including two of which have so far eluded me as originals, disappointed me as reproductions and intrigued me by their construction, they are the rear number plate (stand-off) brackets. Intriguing because they incorporate a ‘bird’s beak’, the metal forming name given to a notch pressed into a fold at right angles to add significant strength, by reducing flex and the opportunity to stress crack.
So, I decided to make them, an interesting little project.
An original example.
Armed with a borrowed nice original, but even that had an additional hole drilled into it, and Mike Sherrell’s book open at his drawing on page 117, I guillotined the blanks from 1/8 inch mild steel sheet slightly over length. I marked out the first fold measured from the number plate end and with that same end clamped tight folded it on and around the line to give the correct internal dimension for the leg length, but the second fold has to be made from the opposite end and has to be marked out to allow for the metal to stretch. If not the stand-off length will be wrong.
My solution is simply to fold a test piece on the second marked out line to reveal by how much the fold creeps, allowing me to compensate when I fold the actual ones and trim the chassis mount leg to finished length.
Drill the holes and elongate with a ¼” cutter in a milling machine, remembering that they are not handed so you cannot back to back drill all of the holes.
Now for the bird’s beak; make two form tools, the first from square bar with the female form of the notch filed across a corner, which has also been radiused to match the inside of the bracket fold.
The second is simply an old cold chisel the point ground down to a tight radius, sufficient to crease the metal without cutting it.
The two form tools.
Mount the square bar very tight in the vice, balance the bracket on it and heat the first area to be notched to yellow. Quickly position the chisel centrally by eye and apply a heavy hammer blow. I had to repeat twice to move the metal all the way.
For the second one, the bracket will not balance on the form tool, so I secured it in place with bolts through the chassis mounting holes.
Clamped to form the second bird’s beak.
The finished result is very satisfying and I imagine that I have recreated the original manufacturing process when perhaps it was a job for an apprentice.
My finished bracket.
Ed’s note: The M.G. TC Factory Specification Book which lists virtually every nut, bolt, washer, screw on the car lists the rear number plate brackets as 81744-z.