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Pretty soon, I'm going to "get motivated" enough to reconfigure (more tuning range / better alignment / smoother action) the "buried" / oddly-configured /stubby #3 slide on the back side of the big Miraphone 98.

I won't be able to (once in place) either put calipers across the tubes, and nor will I be able to sight across the tubas to judge whether they are coplanar.

I'm thinking of building the inside slide on my trombone slide "stone", fitting the outside slides (with nice "as if pistons and casings" type of fitment), sticking it together, and then soft-soldering/tacking on a couple of pieces of junk trumpet mouthpipe tubing across the two outside slide tubes - perhaps with yet a third tube tacked across those two tubes, re-checking for parallel/coplanar, pulling/tugging on the receiving circuit tubing, handling it gingerly during installation, moving/testing receiving circuit tubing until the assembly slides in place effortlessly, soldering in place, removing the tacked-on bracing, and then (hopefully) it will be "good".

What do you (Wade + TFFJ) think of this (pun intended) tack?

(One thing that has prompted procrastination has been the lack of ability to measure and sight it - during installation...and - understandably - the alignment of the o.e.m. shorty slide is - at best - mediocre.)

I always align my slides on my surface plate using some old Starrett adjustable parallels. I build the slide itself first. Then I slip the outer legs on halfway and solder on a brace. To me, this is a complete "slide assembly". After the sliding bits have been aligned off the horn, I will adjust the ends of the two "runners" until they line up with my assembly perfectly. Then I wire the assembly in place and solder the two tube joints.

So for me, only a complete inner/outer slide assembly goes onto a horn. (Piston valve 3rd slide loops are sort of an exception. I build both slides, but only solder the brace to the short side of the lower slide so that I can rotate the long, outside tube on the lower slide, with the upper slide fixed in place. I can then fit both ends to the valves and still rotate the outer tube to accommodate the span of the crooks and THEN fix the angles for good.)

I have used the tacking method as you are doing, but only when the slide will not have a brace between the two outer legs, as with the upper 5th slide on a modern 186 that has two braces to fix the slide to the leadpipe. But generally, I have moved to installing braces between all slide outer leg sets for strength, and this also functions like your tacking, but it can be buffed, scraped, or sanded in advance, off of the horn. Then I only have to worry about cleaning up the two tube joints.


I pretty much build all my slides like this now.

That's just it:

I don't believe I'm interested in bracing it, as each outside tube (oem) has a 3 pc. adjustable brace reaching out to it.