TromboneChat

Hi all

I'd like to know if replacing the inners of my Besson with the ones of my King is doable myself ? I know my way with soldering and slide-adjusting.

- Outer slide of Besson fits on the King inners, but i don't know if the inners are gonna fit in the barrel of the besson, diameter wise ?

- Is the leadpipe integrated in the inner tube ? Cause the King's one is broken in half. I can't really picture in my head how this assembly looks like, maybe some techs have a drawing ?

Thanks in advance for any help

Maybe it's a lil more clear with a picture... I already disassembled the King slide :



I couldn't find any leadpipe, but the mouthpiece fits just the way it always used to, in the upper tube... I remember pulling an old piece of garbage pipe out of that tube, long ago, and assumed it was a piece of the leadpipe... Could have it been ALL of it ? It was well corroded. So... is the leadpipe usually soldered IN this tube or in the cork barrel ?

On the Kings, the leadpipe is usually a two-piece entity......a mouthpiece receiver plus a leadpipe that is soldered into the bottom of the receiver. Since the mouthpiece receiver typically has the same outer diameter as the inner slide tube, the upper inner slides on King trombones are usually about an inch or so shorter than the upper inner slides on one-piece-leadpipe designed trombones.

If you are working with original King equipment, the upper inner slide should be too short to install on that Besson trombone. You need to place the the King inner tube beside the inner tube of the Besson and line up the ends down by the stockings. If it is an original King tube, it will likely be too short to reach the the mouthpiece receiver end. If it does reach the same distance, then two things could be possible: 1. Your Besson slide is extremely short. 2. Your King upper inner slide was replaced with a custom part...possibly a King lower tube in order to create a removable leadpipe system.

Another thing, if you have an upper inner tube with no leadpipe in it, your mouthpiece should NOT fit in it properly. The tube should be too large and it will be straight instead of tapered.

Based on your questions, I recommend that you take your slide parts to a qualified tech.....even if only to get advice. There is SO MUCH that could go wrong with this project and you could end up with a slide that does not work at all.

Not ALL Kings had the 2 piece leadpipes!

If the OD of the Besson tube, NOT the stocking end, is the same, the King tube probably will fit into the Besson cork barrel assembly. If the King tube is slightly larger, you could always machine out the Besson cork barrel to fit.
But yes you also have to consider the length of the tubes.
In your case, it does look like the King upper inner went all the way to the end of the cork barrel, so probably the same for the Besson. But not so for the King lower!!

Also, I'm sure the mouthpiece part of the leadpipe is still in the upper tube if your mouthpiece sits correctly.

As Brian mentioned, LOT'S to consider!!

Thanks a lot for your tips That's why i ask, before i do a mistake that could ruin my slide...



On this picture, both tubes are resting on the table, the upper one is a bit shorter, as you mentioned. Could that be that my red marking is the joint between the mouthpiece receiver-end and the tube itself ?

The King inners are .491, and the Besson's are .487, so they're slightly larger.

Windmill wrote: ↑Mon Mar 15, 2021 11:28 am Could that be that my red marking is the joint between the mouthpiece receiver-end and the tube itself ?

No. As Eric said, older Kings have one piece leadpipes. Even if it does have a 2 piece leadpipe, the part of the receiver that protrudes beyond the slide tube would only be 1/4". The section you're looking at is a different color because it has residual solder on it. That's why you're seeing a "line".

The upper and lower tubes are different lengths because the lower tube inserts part way into the tenon when the slide is assembled.

Allright, so I still got a little piece of leadpipe stuck in the inner tube. How can I get this one out? I tried to stick a mouthpiece in there, heat from outside but nothing moved. I might build myself a conical rod to insert from the stocking end, which could pull on the remaining piece of leadpipe?

More than likely, you'll have to scrape out the remnants of the old pipe as the solder has hardened.
Take a close look at the end of the stocking and you'll see it's slightly peened in which won't allow the pipe to pass that way.

If you have access to a lathe, that would make easy work of cutting out the old pipe.

If you hold the tube up to a light and look through the stocking end, you should be able to see the outline of the leadpipe and give you an idea what's still inside the tube.

So, looking through the stocking end, i do see a small ring, which confirms that there's something still stuck in there ! In the eventuality of successfully pulling it out, and pulling the Besson's leadpipe out without damage, nothing ensures that it will press-fit in the King outer tube perfectly... Mmh... Unless i replace the leadpipe also by a new King one (but where to get that ?), .... and will it match with the rest of the horn ? I compared both bell shapes, and even though they are the same diameter, the throat taper is different.

If the bore is the same, a Besson lead pipe will fit.

Realize that ALL leadpipes play slightly different!! Even of the same model.

I realized that the mouthpiece/leadpipe combination is a real delicate couple. My actual mouthpiece was sticking out from the leadpipe a bit too much, and i gently reduced its shank outside diameter (still keeping it conical), and i realized that the more it was IN the leadpipe, the better was the lower register responding, but the harder was the high register... I stopped where i found the balance quite OK for me But i assume, that with another leadpipe this will change again. The distance between the 2 venturis (backbore of the mouthpiece and the venturi of the leadipe) might be critical.

I go to my tech this afternoon, will keep you updated. One question though : is it mandatory to align the stockings ? Or can they be off-line ?