From the Workshop: Slide Leg Spacers for Trombone

4th June 2021

The key when working on Trombone slides is ALIGNMENT – this is especially important when adjusting the position of, or replacing an inner slide tube. There are so many factors to consider to achieve a perfectly smooth running slide. Minor discrepancies can cause fundamental issues which will keep you going round in circles looking for the fault.

Thankfully, there are a number of tools which help to eliminate the guesswork. One that I swear by is the G35 set of inner slide leg spacers from Ferrees. These small wedges of brass are a simple but brilliant method of aligning the slide tube centrally in the cork barrel. 

When replacing an inner slide tube, I will lay the outer slide flat onto the Ferrees FP90 Granite Levelling Stone, securing it with the magnets holders. We have the FP91 freestanding base for the Stone, but separately it can be held in a vise or simply placed on a bench top. Once the new inner tube is ‘floating’ in the cork barrel, the inner slide section can be inserted into the outer slide as it’s laying flat. This horizontal position is an efficient way to assess the slide action, as you can keep making adjustments before committing to soldering everything in place.

We’ll assume by this point all the slide tubes are nice and straight – depending on the state of the slide when it came in for repair, prior adjustments may be required in the width of the hand slide position, the twist of both slide sections, bows in the legs and of course, dents in the tubes. As well as all of these factors, the new inner slide must be made dead central in the cork barrel and this is where the clever little wedges come in.

They come in a set of 3, but I like to use 4 for extra stability. Place them into the gap between the inner leg tube and the inside edges of the cork barrel, with equal spacing. They can then be tapped in evenly and gently, ensuring the scribed markings on the spacers line up. I like to use the FF11 Canvas Mallet for its precision. You can tap the spacers gently in and out until they’re completely even, secure and holding the tube perfectly central.

They can stay in place while you solder the leg into position, then simply tap them out when you’re finished. I like the FF95 Ribbon Solder – it has a low melting point and the flat shape allows you to be very precise. 

In summary, these spacers offer a neat, clever defense from an almost invisible enemy. Sounds dramatic, but having attempted this kind of repair both with and without them, I would highly recommend purchasing a set or two. If you are taking on involved Trombone slide work and want to save valuable time, it’s well worth it – Abi, Repair Department