Boesy Capo Problem

[David Love]

It does appear that the threads are more of a problem on the nuts than the
bolts so I might get away with it.  I'd like to avoid replacing the bolts if
possible as not only do they have to fit the plate but they are bent at
rather strange angles in order to align with the capo bar.  

That being said (forgive my machinist ignorance) can you not simply cut the
threads on the bolt to a slightly smaller size and replace the nuts with
something appropriate.  Also, what is the gauge called that you use to
measure the thread counter per...?  

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of MICHAEL MORVAN
Sent: Friday, December 14, 2007 8:23 AM
To: Pianotech List
Subject: Re: Boesy Capo Problem

David,
    Referring back to my machinist days I can suggest/explain the following.
1. If the threads were simply ripped/stripped out of the "nut", and the 
threads on the "stud/bolt" are still intact, you can "chase" the threads on 
the stud with the appropriate die to clean them up, and then replace the 
nuts.  HOWEVER
2. If the threads were ripped/stripped off the stud/bolt, you have a 
problem, and will need to replace the studs and bolts. If you chase threads 
that are ripped off a stud, you can get a nut to go on well but, there won't

be enough material left to hold the nut, and as soon as you put a load on it

watch out, it will fail.
3. For further information type "class of fit" in any search engine, and you

will find many articles referring to the relationship of nuts and bolts 
concerning threads and strength.   Good Luck,    Mike

Michael A. Morvan
Blackstone Valley Piano
Dedicated To Advancing The Art Of Keyboard Restoration
76 Sutton Street
Uxbridge, Ma. 01569
(508) 278-9762
Keymaestro at verizon.net
www.pianoandorgankeys.com
www.thepianorebuilders.com
----- Original Message ----- 
From: "David Love" <davidlovepianos at comcast.net>
To: "'Pianotech List'" <pianotech at ptg.org>
Sent: Friday, December 14, 2007 10:31 AM
Subject: Boesy Capo Problem


> Interesting problem.  1890's Boesy.  The heavy metal capo bar is held in
> place by several bolts running through it and held down by some cap nuts.
> Apparently in the rebuilding of this, the threads on both bolt and nut 
> were
> compromised so that as the piano was being tuned the nuts let go and 
> popped
> (probably shot) off.  So the bolts need to have the threads recut and the
> nuts replaced.  Not a big deal but I need some advice on re cutting the
> threads.  The outer dimension of the bolts is .268".  Can anyone suggest 
> the
> best approach for this, tools, thread count, etc..  Machining type work is
> not exactly my area.  BTW  I'll have to send some photos of the bass
> stringing (eastern European rebuilding job).  You won't believe it.
>
> David Love
> davidlovepianos at comcast.net
> www.davidlovepianos.com
>
>
>
>