pinblock drill size

[Ron Nossaman]

Hi Bill,

IMHO, If pin bushings did nothing more than take up space and keep the
tuning pins off of the plate, their existance would be justified. Pretty
much every production piano I've ever seen, new or otherwise, has either
plate bushings, or pins riding on the plate. I'd prefer to tune the former.

Ron 

At 07:13 PM 12/7/97 EST, you wrote:
>Someone mentioned;
>
><<If you are using the 12-ply block, I have the best luck using .257 bit. With
>a 2/0 pin, this is drilling .025 undersize.  This has given me around 125 inch
>pounds of torque for several years now.>>
>
>I don't think anyone has mentioned it, but I have found that one factor that
>causes the great variance in pin torque is - how the hole is drilled. 
>
>I guarantee that you will get different pin torque, using the same drill and
>block, if you are hand drilling as opposed to using a drill press  or a
>portable drill press set up in the piano. Try it on a piece of scrap pinblock.
>
>Also, sharpness of the bit is important. A dull bit will give different torque
>than a sharp one of the same diameter. A dull drill might be just fine if you
>know what you are doing and it gives the right torque. Again, try it out on
>scrap.
>
>Here is a pet peeve - Pin bushings. Most technicians say they add nothing to
>pin torque. I think that is more or less true if they are used as drilling
>guides and a pin sized hole is drilled through them. If, however, you can
>drill the pinblock and then install the bushings and string, they add a lot of
>torque for many years. And the top of the pin is better stabilized where it
>needs to be.  
>
>Try an experiment. - Next time you have an old upright with  about zero pin
>torque, one where you can pull the pins out with a vice grips without removing
>the string, pull out a pin, remove the old pin bushing, install a new one, and
>put the pin back in through it.  You should just be able to tune that note.
>(temporarily) It can add 20 inch pounds of torque.
>
>I know some manufacturers never used them, and I don't like tuning those
>pianos as much.   If not drilled out, I think they also help "seal" the
>pinblock against rapid humidity changes and the job looks better.
>
>Bill Simon
>Phoenix
>


 Ron Nossaman