Scraping rotor

[Tubajug]

A friend wanted me to look at a single horn he received because the second rotor is really hard to move. Oil did nothing. It's obviously scraping on something as it moves. You have to use the stop arm to move it. Just the paddle isn't enough. haven't messed with taking it out yet...I can restring a horn, I just don't like to... any ideas what it might be causing it to seize so much?

[bort2.0]

Might be unseated? Unhook the linkage and tap the stem with the mallet... See if that improves things? Rotors scared the hell out of me until I sucked it up and took some apart. Quite demystified after that!

[the elephant]

There are *many* possible causes of what you describe. It could be that the stem has been slightly bent. The rear bearing plate might not be driven home perfectly straight. There could be some schmutz in the casing. A knuckle might have been tweaked so that it protrudes into the casing. (This can happen if the horn becomes slightly bent, and a halfway repair job could hide the evidence needed to figure that out. You know, *fix* it, but not really fix it.)

Even when you get it apart it could take some careful investigation to sort this.

Rotor issues can be tough to diagnose and fix, but most of them I have come across are indeed fixable. The fact that you can disassemble the whole assembly from the other valves and work on it on your bench makes this possible. I have come across a lot of piston issues that are more or less the same, but that can be easier (for me, I guess) to both diagnose and repair.

I wish there was a maker of specialty tools, like Miller Special Tools, that made "dealership" (or factory, in this case) tools made for one purpose only, but for band instruments. Like Miraphone 186 rotary valve casing slugs or rotor bearing sleeves, like the sleeves and slugs and valve thread chasers made by Ferree's Tools made for use on brand- and model-specific piston valves.

It would be great to have some sort of sleeve to put old rotors into that would allow the tech to test and correct the spindle ends and the fit of the rotor wall. A slug made to fit a specific rotor casing that could be tapped into the casing to make sure the spindle was true, the knuckles were not pushed in, and to test for leakage.

Ah, but I digress. But you see where I am going with this.

Good luck in figuring this one out, Jordan. It could be something very simple that makes you the G.O.A.T. to your friend, or it could make you feel like a complete novice. Do not get discouraged if it is the latter, and keep trying. Post photos and questions if you need assistance from one of us.

[LeMark]

I wish I had a few dollars for the number of time I've had to take apart a rotor during a lesson and clean a layer of lime so thick that it bridged the gap between the valve and the bearing plate, or the valve and any other interior surface of the valve casing.

[bloke]

‘ too many possibilities, such as with the question, “Why does my throat hurt?”

[bloke]

‘ too many possibilities, such as with the question, “Why does my throat hurt?”

post nasal drip. Take an allergy pill

[bloke]

Thanks. I guess I was confused, and misassigned the cause of the pain to this stab wound I received at a gas station in Memphis - while filling up my tank.

‘ too many possibilities, such as with the question, “Why does my throat hurt?”

post nasal drip. Take an allergy pill

[Rick Denney]

I wish I had a few dollars for the number of time I've had to take apart a rotor during a lesson and clean a layer of lime so thick that it bridged the gap between the valve and the bearing plate, or the valve and any other interior surface of the valve casing.

Yup. Just like the most common cause of a sore throat is post-nasal drip, the most common cause of a dragging rotor is lime or slime buildup on the rotor, such that should should be a liquid seal is actually a physical interference.

Rick "proper cleaning is always the first step" Denney

[bloke]

WRONG !!!
Valves ONLY stick because someone is trying to cheap out and using 9¢/oz. valve oil, instead of $5/oz. valve oil !!!

I wish I had a few dollars for the number of time I've had to take apart a rotor during a lesson and clean a layer of lime so thick that it bridged the gap between the valve and the bearing plate, or the valve and any other interior surface of the valve casing.

Yup. Just like the most common cause of a sore throat is post-nasal drip, the most common cause of a dragging rotor is lime or slime buildup on the rotor, such that should should be a liquid seal is actually a physical interference.

Rick "proper cleaning is always the first step" Denney

[Schlitzz]

WRONG !!!
Valves ONLY stick because someone is trying to cheap out and using 9¢/oz. valve oil, instead of $5/oz. valve oil !!!

I wish I had a few dollars for the number of time I've had to take apart a rotor during a lesson and clean a layer of lime so thick that it bridged the gap between the valve and the bearing plate, or the valve and any other interior surface of the valve casing.

Yup. Just like the most common cause of a sore throat is post-nasal drip, the most common cause of a dragging rotor is lime or slime buildup on the rotor, such that should should be a liquid seal is actually a physical interference.

Rick "proper cleaning is always the first step" Denney

Yeah, Reginald Fink used vegetable oil on his Conns for his career. Trombone and Baritone. Nothing to see here.

[iiipopes]

‘ too many possibilities, such as with the question, “Why does my throat hurt?”

Where I work, the answer to similar open-ended questions with too many possibilities is, "It depends. Please tell me more." And the ticker keeps on ticking.

[bloke]

If you are courageous, you can try the PB-Blaster, disconnect linkage, and pliers-and-rag-on-the-stop-arm - thing...

...but you have to have a sensitive enough "touch" (while - simultaneously - "putting it to it") to realize that whether or not its going to break loose or (simply/tragically) break.

The PB Blaster needs to be all over both spindle bearings, as well as the rotor body.

The fringe benefit is that the stinky PB Blaster odor hangs around for about a month.

Since it's a horn (and not a tuba) IF it is just lime/scale, it should break free more easily than a tuba rotor (less surface area) and - thus - less likely to f it up.