I don’t believe I’ve ever had so much difficulty drilling holes. Five #80 drill bits lined up like casualties of war (where are their flags?), and not one successful hole achieved.
#622 had oil cups mounted mid-way down the crosshead guides. They are quite prominent in the photos, and I would love to model them. I couldn’t include any mounting pin for them in the etch because of the way the guides fold, and I couldn’t etch holes for mounting pins because there simply isn’t enough metal to spare as it is. So, I had hoped to drill holes after the guides were assembled, and I spent a good portion of my day attempting this.
Because of the shape of the crosshead guides, the holes need to be on a cusp, and finding this cusp with a #80 drill bit proved to be impossible. The bit wandered off to make a hole off to one side.
So then, I thought of a cunning plan to make a drill guide by centre-drilling a piece of hex stock and then filing it out to fit over the crosshead guide. For some reason, the hex defeated drill bit after drill bit, flicking their points into the ether with disdain. I then tried to drill into the side of a length of rod, and broke the fifth drill bit.
So, #622 is going to lack those oil cups. If I can’t get the holes in the right places, the oil cups will be misaligned and look terrible. If I can’t make them robust, odd ones will break off and look worse.
While the crosshead oil cups are a distinctive feature of this engine, they are beyond me at this point.