Valve Oil, Part II: Rotary Valves  

The woman hovered nervously over her son’s French horn.   

“To tell the truth, he didn’t play much over the summer,” she explained.  “It was working fine at the end of the year, but when he took it out yesterday it didn’t play right.” 

I examined the horn.  It was dripping with valve oil.   

“As soon as he realized the keys were sticking, he oiled it,” she continued.  “But that didn’t seem to work, so we figured we ought to bring it in.” 

It was a classic case, and one I’ve seen far too often in my 26 years repairing horns.  In a way, the woman’s son was right.  All the horn needed was a little valve oil.  But he had applied it about six months too late. 

What Never to Do to Your Rotary Valves 

Rotary valves are found in French horns, trigger trombones and some euphoniums and tubas.  Instead of moving up and down inside its casing, a rotary valves turns around its axis.  Unlike piston valves, which fit snugly in the valve casings, rotary valves contact only at the bearing, a very small area near the top. The rest of the valve floats freely in the casing.   

        Rotary valves should always be kept properly oiled.  Oil keeps the bearing surface lubricated and protects the surface of the metal from dirt and lime. 

But beware: because of all the extra room in their casings, rotary valves will frequently work just fine even when they’re dry.   Don’t do it!  Running them dry can lead to major problems: 

1. Excessive wear on the bearings.  Trust me, you don’t want this to happen.  Refitting bearings is a major (read: costly) repair. 
2. Build-up of lime on the casing and the rotor itself.  Lime is known to repairmen as “nature’s solder.”  Traces of lime from saliva will solidify to a cement-like substance capable of “gluing” one horn part to the next if left untreated. 

Run dry, by the time rotary valves are limed up enough to stick, it’s too late to do anything about it short of bringing the horn in for a professional cleaning. 

Tape This Inside Your Case 

Here’s what I tell beginning French horn students (and anyone else who will listen):   

“You don’t oil your valves so your valves will work today.  You oil them so they’ll work six months from now.” 

(If you’re a horn player you might consider printing the previous sentence out in big red letters and taping it to the inside of your case.) 

How to Keep Your Rotary Valves Spinning  

        You should oil your rotary valves right at the bearing, at the top of the valve.   

        Some older French horns have an oil port built right onto the bearing shaft.  All you have to do is pull a screw and pour oil down the hole.  This makes it easy.  You can usually tell if you have one of these models because the oil port will say “OIL” right on it.   

        Unfortunately, it’s not so easy to oil most modern horns.  For some reason it’s no longer popular to manufacture them with an oil channel.  Still, it’s got to be done.  We find that the best way is to use a pin-point oiler.  This is a small bottle with a needle-like spout.  You can order one through our shop – they take the hassle out of rotary valve care.  

When you’re playing hard, you should be oiling your rotary valves daily.  Otherwise, count on doing it at least every other day for optimum performance. 

        If you’re unsure of how to oil your valves, bring your horn in and I’d be happy to show you.  I’d much rather spend a few minutes teaching good preventative maintenance than be faced with an oil-drenched last-minute emergency! 

-Dan