Pianotech

Hi piano colleagues! 

A moving company reached out about having moved a customer's piano and upon arrival there was no socket in the legs to accept the casters. They're quite large with a threaded end (see photos) - I've emailed Steinway parts for an idea but wanted to check here as well. 

I've not encountered this type of caster and curious if anyone has some insight on how I can help this person get their piano upright on solid legs and wheels! 

thanks!!