You need to silver braze those joints. Use something like Eutectic 1020. Clean both pieces thoroughly and use a borax flux. The braze will be sucked into the joint by capillary action, and clearance should be minimal for a strong joint.
Those are pretty much Model T vintage. The Model A and later ones had a square handle tip that was used for the drain and fill plugs on the transmission and axle housings.
I have a Vertex like yours, but it came with a swappable 3-jaw chuck and a set of indexing plates in various numbers of spaces. They have tapered notches for a movable stop plunger to engage. Should come in handy for doing bolt circles.