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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