Wednesday, June 15, 2016

Frank's Dirty Pictures- Part 1

Do your horn rotary valves feel sluggish or even get stuck at times?  Any amount of oil still not correct the problem?  
This includes you rotary valve tubists!

Well... they may be dirty.  

Rotary valves have particular issues not found with piston valves.  Anything from food particles, deposits caused by the reaction of our acidic 'nature' to brass, improper lubrication, and drying lubricants from lack of use (are you practicing?) can cause gunk to build up.  If the instrument sits around (especially in a barn/attic/garage) for a while, it can make it worse.  The close tolerance (spacing) in the construction of rotary valves causes these issues to occur. 

IF you were to take the rotorary valve apart (don't try this at home), they would probably look something like this:

In order to alleviate the problem, a properly trained repair technician would generally chemically and/or sonically clean and buff (polish) the rotor, back bearing and casing.  Once completed, they would look like this:

Rotary valves can be difficult to maintain.  Unlike piston valves, it's a lot harder to lubricate a rotor.  There are more spots and harder to get to.

There are three places to oil.
  1. You can reach the rotor directly by dropping oil into a tube.
  2. Take the cap off and drip a drop on the middle of the back bearing.  If your horn has tight suction, pulling the tuning slide will suck the oil through.
  3. This one is tricky.  The goal is to get a drop on the spindle between the gap of the stop arm and stop plate.  It helps to have a needle tip bottle for this one.

Here is a link to a more detailed explanation of lubricating different parts of the instrument.

If you have any issues with your rotors or anything else, we can help you.  We have experienced repair technicians and lubricants and supplies to help with any problems you may have.