Teflon thingees help

[Ken Jankura]

At 06:03 PM 3/7/99 EST, you wrote:
>Del,
>
>I defer to your experience on the durability of the teflon bushings.  I am
>sure you have serviced many more than I have.  Maybe you are right;  the
>problem was not the expansion and contraction of the wood around the
bushings,
>but instead it was the result of improper reaming and fitting techniques.  Do
>you have anything to add to the Steinway bulletin regarding servicing teflon
>bushings?    There are still quite a number of teflon actions in service.
>Would you mind being more specific about the various techniques - types of
>reamers, the acceptability (or not) of the centerpin rolled in a file, etc?
>
>I am interested in the comments of others who have serviced a considerable
>number of these actions also - do you mind speaking up here?   Thanks - 
> 
>Bill Shull
>U of Redlands, La Sierra University
Dear List,
    I am showing my ignorance here, but I'm bored with just showing it to a
small circle of friends, so why not an international list of my peers, but
where can I find basic info about teflon stuff (my journals only go back to
'91) The general reaction I get from other techs is "replace it". Is there
a a section in the S$S service manual that covers this? I have the
misfortune of having a large percentage of the S$S that I service of the
teflon persuasion. The killer is a local music school with about 10 turn of
the century S$S that were re'actioned' in the 60's (need I add that there
is no money to replace parts).
   Does the Don Mannino broach type reamer system work? If they seem a
little sluggish, should I presume that the pin is bent a little and
replace? Or just that it is winter and they will get looser come summer?
I've done a few and found that a little reaming goes a long way, that is ,
a couple of swipes goes from 2-1/2 swings to 10 swings. I'd rather have
them a little loose than effect touchweight so much, or should I say
toughweight.
   Newton says he has used regular pins, any other input on this? I've
tried gently deforming (enlarging) the hole by rotating a pin off-axis on a
couple. Is this OK? Will it be way too loose in the Summer? Should I just
tell my clients to expect a touch of tendonitus in the winter :-) I've done
the hole-in -wood-test-then-measure-it-under-different-humidity-conditions
(the hole acts like wood would). My take has been that felt and wood have
this symbiotic relationship thru the seasons, when the hole shrinks in dry
weather, so does the felt, when the hole gets larger in humid weather, the
felt takes on moisture, and in both extremes the friction changes less than
you would expect. This teflon inert thing has me wondering whether I can
accurately predict what is going to happen next season.
   Has this been covered ad nauseum in the past, I'll gladly search the
archives. Thanks.
Ken Jankura, RPT
Newburg, PA