PCBway community page for an adapter for a Commodore 1541-series disk drive. Makes it possible to add a parallel interface port to the drive for the purposes of disk ripping. Rather than cutting traces and soldering directly to a 6522 chip, it fits in between the chip and its socket. Add some ribbon cable and a DB-15 plug and there you go.

The picture is a helpful reference for how the IC socket and header bars are positioned.

Note that, per the response to my question:

Pins 9 and 10 are connected to pins 18 and 39 of 6522 - CB0 and CA1 (some count it from 1 so it's CB1 and CA2 then). They are needed only when drive is connected with C64 via userport to handshake while sending data. You don't need those for XUM1541/ZoomFloppy.

How to build a simple circuit that measures the amount of power left in a battery and display it in increments with a set of LEDs.

A suite of open source electronic design tools. Uses a GUI for schematic capture. Also capable of analog and digital simulation, generation of parts lists and export of PCB designs for fabrication.