(Straighten, Parallel and Level)
The idea for constructing this series of pages on the technique and approach for slide action repair evolved steadily over the past several years. Many of our out of state clients that have never been to our shop have expressed great interest in just how we go about repairing their slides. Or what Daniel Oberloh refers to when he says, "Trombone spell," or "Spelling a slide."
The following pages are not only intended for interested trombone players but hopefully are found beneficial by repair technicians. Technicians such as myself who are always looking for sources in adding to, improving and updating their existing skills. I hope you find enjoyable what we have put together.
Evaluation and Preparation for Repair
Here is a trombone slide that didn't work very well, a typical problem we see all the time. This particular slide was from a Yamaha YSL-456G.
Look, you can defy gravity. This is the special conductor's model, the slide stays in one place so your hand is freed up to cut off the band. Actually, it is a slide with a number of problems. The first step to restoring slide action is determining what those problems are.
I will almost always start out by placing the slide assembly on our handslide leveling stone. This is our slide leveling stone, made by Ferree's Tools of Battle Creek, Michigan. The steel rails (A) seen on the stone running across the width are ground very level and have pins (B) that are fixed to the rails. The six brass sets (C) are magnetic and are used to hold in place and/or manipulate the tubes as needed.
Slide Leveling Stone, Ferree's tools, item #P90
When measuring the slide, I always measure from the "fixed side" (the side with the pins seen to the right.) I use a high quality digital caliper trying to get measurements to .001 inches.
I typically measure at the crook end, then the opposite end, about four inches down from the cross brace, and finally in the middle. Note: Many outside slides have a wider girth or secondary sleeve around the actual slide tube up near the hand brace, for example, most Bach Stradivarius standard weight slides. The cross measurements at this point should be made as close to but not on these wider areas. These wider areas will give you a false reading.
This slide was measured and with the following results:
Crook end: .000"
Brace end: +.012"
The slide was narrower at the crook end than it was at the brace and even more so in the middle, sort of an hour glass shape. Plenty of reasons for this slide to function as poorly at it does. Those were not the only problems found.
The only way to straighten the slide correctly and with lasting results, you have to take the slide apart...
...not just a little bit apart...
...all the way apart!
Since we will be realigning the outer tubes, we will need to realign the inner slide as well to match the outer slide's alignment.
Clean all the old solder off while you're in the neighborhood. If you leave it behind or try to "reuse" it, your connections may or may not have problems, why take a chance! Cleaning your joints makes the work easier and smoother when it's time to reassemble.