James,
Hammer rise after back checking is the traditional indicator of whether or not there is enough repetition spring tension. However, in our shop we call it "manifest" repetition spring tension, as a reminder that there are other factors in play besides the spring itself. In other words, while hammer weight is a constant (from one blow to the next, if not over the life of the hammer), friction at the various contact points can change (such as key bushings and action centers, particularly the repetition lever/balancier and hammer centers).
So, if hammer rise is insufficient to indicate that the jack is able to promptly return under the knuckle ("follow the jack!"), it is a good idea to carefully inspect the relevant friction points before adjusting the repetition springs themselves.
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
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Original Message:
Sent: 04-10-2018 00:00
From: James Kelly
Subject: Kimball grand rep springs
I need to get some tension in the rep springs of a kimball grand. The rep spring does not have an adjustment screw nor is it a butterfly stype spring. There is a loop that the end of the spring is connected to. the jack spring has a loop on the jack just below the jack adjustment button & felt. The springs are independent of each other. The balamcier spring end is hooked to a loop that passes up through a hole in the balancier. The question is how do I add some rep spring strength so the hammer will come up after checking and key release ? do i message the spring where is has a coil on the balancier , pull up on the spring with a hart tool, put a bend in the spring or push down on the spring back near the coil .? few if any rep levers seem to have any rep strength at all
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James Kelly
Pawleys Island SC
843-325-4357
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