Thanks, Kathy, that is very helpful.
In my case, a visiting show (Mark Morris Dance) complained about the casters being loose and making noise when the pit moved. They resolved it using cord as you described, but the bug is planted with the technical staff that maybe the casters need to be replaced or serviced. I mentioned it would be quite expensive.
It looks like the brake ring tightens around flanges in the two wheels, and that eventually the "teflon brake drum" (as labeled in the photo, the lining on the inner surface of the "center brake ring") would wear through, especially if the piano were pushed around with the wheels not quite locked. Once the teflon padding wore through enough, the "center brake ring" would be completely closed (incapable of further tightening). Hence, tight enough that it won't go rolling off, but not really snug, which describes my situation.
It looks like the real challenge (once the puzzle of getting it screwed out of the socket had been solved) would be removing the axle, whose end nuts aren't made for unscrewing. Then, once apart, would one be able to procure replacement parts? Presumably in my case the needed replacement part would be the center brake drum with teflon attached.
It all seems theoretically doable, assuming parts could be had and would fit on casters 20 years old (ie, the design hasn't changed in the meantime), but the logistics of having all the casters off the piano would be quite a challenge, especially since the piano is an hour away. Having resolved that problem, taken apart the casters, and finding that in fact the new part doesn't fit, we'd be in a big mess. (If it were at the university and I was working there, I might be able to figure things out, doing one at a time).
If they follow through, I'll tell them we need to order new casters. If they do, I can take one home and have fun with it :-)
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Fred Sturm
University of New Mexico
fssturm@unm.eduhttp://fredsturm.nethttp://www.artoftuning.com"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
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Original Message:
Sent: 02-11-2023 16:43
From: Kathy Smith
Subject: Steinway D casters
Hi, Fred,
Enough people have asked for that photo that I will try to add it here. (I've been known to fail at that, so I'll give it a try.)
To reiterate, I did not take the photo. It was taken by a tech (not piano tech) at Rice, who contacted me because his failing caster also had a cracked socket and I had a spare. (Our communications occurred a week after Dean Shank had passed away).
In his words, he sent the casters to the "campus research machine shop" where they pulled one apart and he took the photo. He later annotated the photo. In the long run, he said he didn't think it would be worth most people trying to take one apart.
He said: "The round cap on the end of the axle is threaded and can be removed with padded-jaw pliers, though we milled a flat on one to remove it with a wrench. The problem is that the brake rings are stripped. We will put Helicoil in the hole and re-tap the threads. The tightening shaft threads here are quite solid. Also, the brake 'drum' material is a kind of a hard plastic that gets worn, and the inner ring of the wheels gets grooved. We will smooth that out and either replace or shim the brake 'drum' material. We will also clan and lubricate the bearings, which appear to be in good shape but are dry."
They later took off another caster and found that the shaft was slightly bent though the socket was intact. Their shop straightened that shaft and put that one back together.
If anyone pulls one apart in a piano-tech level shop and has success, it would be good to add photos or procedures to the group knowledge base. Those casters are pretty expensive and sometimes hard to wait for.
In several cases, casters that fail to lock well (rolling when locked but otherwise safe) were used for a few more years by using 1/8' black cord, which is everywhere around a stage. You can use a piece 8-12" long and just wrap it around the contact point where the brass caster wheel meets the floor. It is surprising effective because the caster won't get rolling if it can't get started, and it's cheap, and invisible from the audience.
In addition, I spend a lot of time explaining to crew that "snug is good, tight is bad" when locking these casters.
Kathy
Original Message:
Sent: 2/11/2023 3:48:00 PM
From: Fred Sturm
Subject: RE: Steinway D casters
Hi Kathy,
Would you please send me photos? I have recently taken on a Hamburg whose casters don't quite lock. Would like to see in advance what I'd be getting into.
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Fred Sturm
University of New Mexico
fssturm@unm.edu
http://fredsturm.net
http://www.artoftuning.com
"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
Original Message:
Sent: 12-09-2022 12:35
From: Kathy Smith
Subject: Steinway D casters
Hi, Dave,
I've done a lot of work on the large brass concert casters. I have some photos, including a picture of one all torn apart and laid out. I'd be happy to share those with you, offline or online.
If you haven't taken one off the piano yet, you may not have seen the stem and socket situation. You'll see that the stem of the caster is threaded at the top, and it turns into matching threads on the inside of the socket. Both the caster and the sockets have flanges which come together when it's in place, and you'll see that the bottom/outside flange, for the caster, has two slots in the perimeter. A special spanner tool (which I obtained from Yamaha, or you can make one) makes that easiest, if they're locked together rightly. If it's already a bit loose, as is shockingly common on concert pianos, you could spin it off with your fingers.
Let me know if you want the photos. I sold a spare socket to a technician (not piano technician) at Rice in Texas. He had sent his caster to their pretty professional experimental lab which had metal-working capabilities. His repair included some milling and fashioning of a new "brake" material, and he said the average person would NOT want to disassemble one of those.
Just curious, what is making you feel like the bearings need service?
Kathy
Original Message:
Sent: 12/9/2022 8:39:00 AM
From: Dave Conte
Subject: Steinway D casters
Hi, all.
Does anyone know how to remove and disassemble Steinway New York D locking casters so I can service the bearings?
TIA
Dave
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Dave Conte, RPT
Resident Technician
The University of Tennessee
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
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