Slide Trombones

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Analyzing Slide Trouble

There are so many causes of slide trouble that it is valuable to know how to analyze the cause quickly and eliminate the trouble. Correct diagnosis of the trouble is half the battle, just as in correct diagnosis of auto or radio trouble. Usually the trouble is minor but if you tinker and experiment blindly you'll have a major repair job before you're through.

If the slides work well when dry but begin to drag after oiling, look into the following:

  1. Maybe grinding powder used by manufacturer when he ground the slides in has become loosened by the oil and is acting as an abrasive. This fine grinding powder sometimes becomes imbedded in the inside surface of the outside slides. As long as it stays in the tiny pockets in which it has become imbedded, you have no trouble with it. But when oil is applied, the particles are flushed out onto the slides and trouble starts. The only remedy is to oil and clean, oil and clean, until all the particles are removed. This may take weeks but usually it will clear up in time.

  2. The other cause has been touched on under "Cleaning Cork Barrel," above. Sometimes the original grinding powder has not been well cleaned out by the manufacturer, or sometimes dirt accumulates in the cork barrel. When the instrument is dry, the dirt is not dislodged and causes no trouble. But when oil is applied to the sides, the outside slides push oil up into the cork barrel and then pull the loosened dirt out, coating the inside of the slides. This dirt spreads over the slides gradually. At first you have trouble only with sixth position, then you feel it in fifth, and so on up, until the inside of the outside slide is entirely fouled, as well as the stocking on the inside slide. The remedy is to clean out the cork barrel and keep it clean.

If your trombone works all right at first after cleaning and oiling but begins to drag and bind after awhile, investigate these possibilities:

  1. First hold your hand slides up to the light and sight down their length. You'll probably be amazed at the dents and dinges revealed. When the slides are inspected in the ordinary way, you cannot see these dents, but when you sight down the slides they loom up. The chances are that one or more of these dents are the source of your trouble.

  2. Remember there is only about .003" (three thousandths of an inch) clearance on a side between the stocking of the inside slide and the inside of the outside slide. The dent may extend only .001" to .002" (one to two thousandths of an inch) on the inside of the outside slide. This may not give you any trouble when you start playing. But as the trombone becomes warm it expands. The dent which gave no trouble when the trombone was cool begins to drag when the trombone becomes warm and expands. If you'll lay the trombone away until it becomes cool, it may play all right again for awhile. Then, when it becomes warm through playing, you experience the same trouble. The only remedy is to have the dents and dinges removed. A repairman can run a ball down the slide and locate the dent. This ball will be the diameter of the slide and will rub or bind when it reaches a dent.

  3. More difficult to locate is another source of trouble of the same nature. Slides become slightly sprung out of parallel. Often this has been caused by dropping the hand slides on the slide crook. The drop may have been slight, and when you picked the slides up and worked them you may have concluded that no damage was done. But when you get the slides warmed through playing, the slightest springing out of parallel becomes more pronounced and the slides begin to drag and bind. The only remedy here is to send the slides to a good repairman who has the necessary precision tools to check the slides. If your repairman does not have the necessary precision tools, the trombone should be sent to the factory.