Thanks for all who responded to my post. As I stated in my post, all three pianos had the large casters and not a spider dolly. These three incidents occured at three different institutions that I work for. All three incidents happened within a year. This makes me think that extreme weather/dryness in the past couple years may have been a factor in the legs plate scews getting loose as Jessica Masse suggested. The other thing all three pianos have in common is that they have all been in service for many years and have been moved around on the large caster without incident. That makes me think that the casters work Ok if the piano is handled carefully, but that the screws tend to lossen over time, perhaps more than they would if the pianos were on a spider dolly.
The thing is, I assume that the purpose of these extra large casters used on concert grands is so one does not have to spoil the asthetics of the instrument and sacrifice some of the tone, by automatically putting it on a spider dolly. Thanks to Jessica and Fred Sturm for pointing out that the use of a spider dolly does not guarentee you will not have porblems with a broken leg. I think the danger of an accident comes mostly after the leg plates have loosened with time. I appreciate John Ginter recommendation of a Grand Transporter. This was indeed the solution we found for one of the institutions and it is what I plan to recommend the the client that just had this issue, as they have at least three pianos they can use it on.
My lesson learned is to check the legs on institutional pianos that are moved around regularly at least once a year by removing them from the piano and checking the leg plate screws if they have plates, or check whatever system is holding them on. The other thing that has occured to me just yesterday, is that I should be checking all these leg plate screws each time I move a piano. Since I also offer piano moving services, it makes sense to provide a more complete and better service by checking the snugness of all grand leg plate screw each time I set a grand piano back up after a move. I have taken a couple classes on paino moving. I don't think this was ever mentioned.
PS. Thanks to David Graham and Jessica Masse for taking the time to share some repair tips.
Sincerely,
Russell Schmidt , RPT
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H. Russell Schmidt RPT
Lexington KY
(859) 276-5015
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