TubeNet

Hi-

I wanted to tweak my Alexander 4v CC. A new gold brass lead pipe is coming from Germany and the old one will be taken off, sent off with the new pipe and bent, and returned and put on the horn.
In the meantime, I wanted to change out the 'T' bar tuning slide mechanism to rt thumb operated mechanism. This is very handy for extreme low register on a 4v CC tuba. Turns out the tuning slide was out of alignment, so it was a REAL headache for my repairman ( in his words, this is THE LAST ONE I ever will do)!


Before: with 'T' Bar


After: with right thumb trigger


Above: close up

The new mechanism is removable and can be adjusted ( thumb position especially). I am going to play with it nail the new pipe arrives, then when old pipe is removed, will have 'adjustments' made from my experiences with the mechanism.

Mark

That looks great. One question. Did the slide mechanism work smoothly even though the tuning slide was out of alignment? I have wanted to have something similar to your original setup installed on my 5/4 Rudy, but all of the techs I have discussed it with are reluctant because the tuning slide has two different diameter tubes.

Hi-
With the T bar, it was fine. With the thumb trigger, it (M.T.S.) needed to be aligned just right.
Mark

happyroman wrote: I have wanted to have something similar to your original setup installed on my 5/4 Rudy, but all of the techs I have discussed it with are reluctant because the tuning slide has two different diameter tubes.

Different diameter tubes should not make any difference provided the alignment is decent and the push/pull action is not yanking the slide to one side or the other (you want it moving straight up/down).

I actually had a T-handle tuning rod on my Alexander 163 when I got it which worked fine before I decided to have it removed completely. The slide alignment was good enough for it to work without dragging and slide alignment didn't seem to be an issue. It never occurred to me that maybe that design doesn't need perfect slide alignment but I can see that a smooth trigger action would require better alignment than a T-bar setup that you can muscle in and out.

In order for main slide 'kickers' to work properly... the alignment of the outer tubes and the main slide assembly has to be PERFECT. This becomes a real pain in the *** if the slide is 'undersquare'. That's a term I learned from working with Chevy small block engines.... when the stroke is shorter than the bore.... when working with slides that's when the tube length is less than the span of the slide crook. Case in point... like the situation found on most trombone bell section slides.

For main slides to be loose enough to function... they also leak.