Glockenspiel pitch change

[MStaples]

I have a 2 1/2 octave student glock with steel keys that are tuned to A=442.  I'd like to change its pitch to A=440 since everyone else in the local contra dance pickup band I'd like to join (read: annoy) tunes to A=440.  From all I've read in this forum and www.makeamarimba.com it seems clear to me that this would be an easy mod by simply grinding (very carefully) beneath the midpoint of the bars (the fundamental note's anti-nodal area) to lower the pitch.  Using an online calculator, I believe that I need to lower the pitch approximately 7.85 cents.  Before I ruin a perfectly good set of bells, I thought I would run this idea by the group for confirmation of my plan or any other ideas about my goal.

MS

[Jim McCarthy]

In terms of the job Michael, you are pretty much on the money! It shouldn't be too tricky and it's just a matter of grinding a tiny bit in the middle of the bar as you say. Even if the instrument has overtones tuned, you can't put them out by an amount that will matter if you are only dropping the fundamental by a few cents.

before you proceed however, I would recommend doing a little online research into what tunings are actually desirable for glocks. It also would be worth using your tuner to get accurate readings on all the bars as they currently stand.

Many people actually prefer to have higher pitch instruments like glocks a little sharp to fit in with stretch tuning principles - google "stretch tuning". Also just because the sound of the glock is supposed to be bright, having it a little sharp can help its sound.

I'll be interested to hear what you find out!
All the best
Jim

[MStaples]

Thanks so much for the information, Jim!  I thought I could adjust the pitch with a little grinding, but I had concern that there was more to the big picture than I was aware of. 

MS