Fork Strength for Drum Brake
I have a question for a frame builder familiar with strength requirements for a fork to run a drum brake.
I'm restoring a vintage ladies step through frame circa 1940s - long frame with 28x1 3/8 wheels. Originally the bike was only set up with a coaster brake - the front fork is not drilled.
The bike is for my girlfriend and while she prominently uses the coaster brake to stop she'd like the extra security of a front brake. I don't want to drill the fork for a calliper brake. I'd rather use a drum brake.
The brake I'm considering is a Sturmey Archer X-FD
The frame is steel, rather heavy but I'm not sure of the tubing - it's a Malvern 2 Star for those familiar with their bikes (Australian Brand). The overall condition is excellent.
I have seen bikes of a similar era which ran a front drum brake and have seen similar style bikes from Pashley, Gazelle and Kronan - though I realise the later are purpose built with the arm support built into the fork.
I guess my question is - were frames back in the day built using heavy steel which can handle the stress of a drum brake or were specially made to use them?
I can imagine the stress could be quite high on a touring or tandem bike down hills but the set up I'm putting together will be for mostly flat, inner city riding where the brake is supplementary to the coaster brake. I just want to make sure it's not going to destroy the fork or worse put my girlfriend in harms way if the fork seizes.
Any advice appreciated.