Zen and the Art of Bicycle Building: how i brazed the front dropouts

first i had to get everything to fit together nicely. as i mentioned before, i had trimmed a little too much from the tips of the blades, so i added a mm or two of rake on the bender, covered in the last post. then i trimmed the dropouts, getting the plug nice and square with the lip. at some point i notched the top of the right blade to avoid mixing them up, from a tip in the Paterek Manual i think.
i discussed the brazing with one of the sculpture faculty who's also a good brazer. i said i didn't think i could easily pin a plug-in drop, so i wanted to braze in the jig, but i was worried about setting fire to the thing. she agreed, and said i could make guards for the jig, but that plywood doesn't tend to burn quickly so it can simply be blown out. she said folks usually wet their plywood jig before brazing/wleding in them, but i wanted to avoid ever wetting the jig so it stays as true and flat as possible.
so i set about shearing and bending scrap steel to fit the area of the jig near where i'd be heating. this was successful in preventing a lot of flame-up, although the maple rake block did catch fire briefly. i blew it out.
so here's the dry fit, checking that everything is aligned and that all the guard pieces are in the right place. the jig is clamped vertically in a vise.

the side view, now with flux. the drops are clamped down, with flux covering all surfaces that contact the drop. this got all the hardware fluxy, but i figure i can easily get new washers and nuts if need be.
note the piece of steel between the dropout and the rake block. this is a sliding guard for the rake block, U-shaped and bent around it, so it can slide to the top or bottom of the block, guarding it or out of the torch's way, like for heating the hub side of the drop.

another view, showing the sliding guard a little better:

i wouldn't say it was a hard braze, but it was a little nerve-wracking, because i had no way to confirm that i had done a good job. i tried to compensate by basically pouring the silver into the joint, adding more than i figured i would need. this resulted in a few clumps of 50n on the blades, but it comes off easily enough.
i mostly brazed in this configuration, with the jig vertical, so the silver would flow down into the blade, but i also briefly fed silver into the 3/32" vent holes i had drilled, tipping the jig so the drops pointed diagonally down, persuading the silver to flow the opposite direction. how well this worked, i dunno. it did make the vent holes fill up with silver, so i drilled them out again afterward.