Yam C7 Loose tuningpins

[Richard Brekne]

Ive seen several cures for this suggested through the years. But the 
best I've run into is to <<brush>> up the hole with a steel brush... the 
kind that can be mounted in a drill. The brush needs to be  very near 
the same diameter of the hole. And you dont want to do anything more 
then rough up and clean the surface of the wood. So just a couple quick 
shots at high speed, moving up and down. Repin one size up and all is well.

Every time I remove a sticky jumpy pin and inspect the inside of a hole 
it shows a dark brown glaze over significant portions of the surface the 
  pin is supposed to grip. There are probably several possible causes. 
Bad drilling... something in the wood at that area... perhaps even some 
foreign substance (liquid) getting in the block. I'm not sure how 
important it is to know the cause, as long as one can insure a cure.

Cheers
RicB

Gevaert Pierre wrote:

> List,
>  
> Tuned a two years old Yamaha C7 yesterday and was surprised to find 
> about 8 loose and jumpy tuningpins in about the same area, ( G4 to D4) 
> while the rest of the pins where normaly tight and smoothly turning.
> I was wandering why this happend (bad drill? to fast feed rate and thus 
> to much heat while drilling? other reasons?)
>  
> While the client asked to the seller to fix this problem with the 
> guarantee, I was just curious to know how such a problem can be solved? 
> (remove the offending pins, clean the hole with a pinhole brush and 
> repining  with two sizes larger pins?)
> Would these pins stay jumpy after repinning?
>  
> Thanks for any advice,
> Pierre Gevaert
> Belgium
>  
>