[pianotech] Kohler & Campbell Hammer Springs

[John Ross]

I wouldn't just replace a few. Because they are all contaminated and will soon go as well.
The spring rail felt of that era wasn't "rinsed'" properly and were contaminated so that it corroded the spring.
When replacing the springs, remove that strip of felt that touches the coil. It might have been a Pratt-Read problem.
Remove the old springs,
I have had good success with mini wire cutters, just grabbing the end and pulling it out. Don't use too much pressure, or you will cut off the wire.
Drill an extra hole next to where you removed the old spring. So use a piece of coat hanger or welding rod, thread the coils on this and it keeps them in line. Then thread the end of the wire through the hole and feed it into the second hole and draw it tight. Glue on the felt over this and it will be secure.
Be sure and average out the tensions and make sure the customer likes the feel. The first time I did the job it was for a seniors residence and they thought the spring pressure was too much.
Someone recently did the whole job using the ones that screw on, he liked the end result.
I like doing it the other way. Screws have a habit of loosening.
With no problems, I can't see it taking 5 hours. Actual labour probably closer to 2 hours, then you have parts and travelling time.
John Ross
Windsor, Nova Scotia
On 11-05-2012, at 10:24 AM, Paul Milesi wrote:

> 1980 Kohler & Campbell 41.5" Mahogany Console, good condition, except that several hammer springs have broken up close to the rail/coil, of course causing hammers not to return.  Springs do not appear rusty, but have what looks like verdigris at the coil.  Might this have caused spring weakness?  Not sure why they are breaking.  Piano is very clean, rust- and mold-free, etc.  Excellent, even tuning pin torque throughout.  Anyone know anything about this era of K&C consoles regarding hammer spring weakness?  They do not seem like very strong springs, very thin wire.
> 
> Also would like to know if the spring rail will remove easily without taking other parts off the brackets…this will be my first time doing this job if they opt for it.
> 
> They have already mentioned, even without a quote yet, that they thought this would be a rather expensive job considering they only paid $300 for the piano.  I'm thinking I'd have to bill 5 hours total for this work.  Thoughts about whether it is worth doing this job on this piano?  Everything else looks in "good" condition.
> 
> Thanks.
> 
> Paul Milesi RPT
> Washington DC
> (202) 246-3136 Cell/Text
> paul at pmpiano.com
> http://www.pmpiano.com

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