Hi Phil, This system likely has an additional coil spring pushing down on the damper tray. One spring is enough if all is cleaned and relubricated lightly and the conversion performed a la C. Ball. I have done many of these conversions and I use a 5/8" punchings, a 3/8" dowel and do not enlarge the pitman hole but do remove the felt. Locating the 5/8" hole in the lever and in the tray are critical for this conversion. I have made a special fixture that I screw to the tray that has a 5/8' hole in it to guide the Forstner bit. Any questions give me a shout. Newton
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