Miraphone 84-B twin-spin

[Rick Denney]

Looks great from this angle. Yes, better than Du-Bro ball ends :) If it works well, stick it in the case.

Rick "looks like they belong there" Denney

[bloke]

Looks great from this angle. Yes, better than Du-Bro ball ends :) If it works well, stick it in the case.

Rick "looks like they belong there" Denney

Those LONG vertical screws - not being Minibal...and threaded all the way up - are NOT an absolute perfect fit though the Minibal links...and to both eliminate most of the side-travel AND eliminate screw-to-link slop, they have to be tightened down "just so".
- too much, and the nylon washer grabs the link
- too little, and they click against the not-Minibal threaded-all-the-way-up screws.
- no control washers, and the Minibal link can possibly click (sideways travel) against the stop arm.

I'm thinking I'll deliver it as-is, and allow the owner to experiment with the set-up as it is, and then (possibly?) with the nylon silencer washers removed and the screws cranked down "hard". As it's currently set up, the lock washers (in the old S-arm space) are the key to dialing in the adjustment...which is very finicky.

The bumpers are also quite hard, which doesn't particularly contribute to silent action.
The crappiest Asian instruments use SUPER-soft bumper material for an obvious reason.

Yet another thing to try would be to coat the top 3/16" of the threads (of the long screws) with Plasti-Dip.

Obviously, one could (more trouble than simply BUYING some BLANK stop arms from Miraphone, but...) drill the upper holes in the S-arm style stop arms to 3/16", silver-braze some little chunks of 3/16" brass rod into those holes, re-drill them, tap them out to M3 X .5, and use the oem Minibal screws, but - huh-uh - not today. (I'll probably include some of those screws with the tuba, if someone else would like to do that.)

[Rick Denney]

Who knows? The buyer might be handy.

Rick “or not” Denney

[the elephant]

… I really do NOT like fashioning aftermarket rotary linkage.

I love scratch-building linkages. It is very rewarding work. It isn't "dent pounding". It is mechanical work with a small amount of engineering involved, and very detailed. I also love designing and scratch-building levers. Different strokes, I guess.

O Sybilli, si ergo. Fortibus es in ero

Right up there with:

Mairzy doats and dozy doats and liddle lamzy divey
A kiddley divey too, wouldn't you?

If you want "clever" pseudo-Latin, this is much better, IMHO:

Quando Omni Flunkus Moritati

[bloke]

Another tack (the one most resembling a no-brainer “parts-changing“ tack (along the lines of modern-day automobile “technicians”), and involving the least amount of adaptation) could be to purchase four nice new “blank” Miraphone stop arms - perhaps with undersized pilot holes (for attaching the Minibal links) in the tops. My experience is that the two-sided Miraphone stop arm stem holes - these days - are a little bit smaller - in size - than the early Miraphone two-sided stems, but (often: slightly bunged up) old stems are easier to sand and file down to fit new stop arms than filing out the holes - in stop arms - larger.

Actually, Miraphone is accommodating enough so as they would probably be willing to not just put a pilot hole in a blank stop arm, but would be glad to tap a nice 3 mm thread.

If this tack is approached, I can help with stop arms acquisition. For purposes of a particular rendezvous (considering how we have to work things these days - due to our rulers having ruined everything), I’ve simply run out of time to have more customized parts mailed in from Germany for this instrument.
—————
Regarding the “pig Latin”, that’s a very old saying, but it has an extremely current implication, and was included for very specific reason.

[the elephant]

I'm not sure I get you, here. Blank what? Stop arms for S arms or stop arms for Minibal links? I also don't know what you mean by "two-sided" in this context. Sorry. Photos might help, here.

If you are going to buy new stop arms to adapt for Minibal, just get the Minibal ones in the first place. The modern half-round rotor stems cannot use the older S arm stop arms, of course, but the half-round stop arms fit the old house-shaped pentagonal stems just fine. They do not slip at all. The ones made of brass are about $13.50 each right now, and the part number is >>> 003313000650 <<< and I have a photo below to show how they fit. It is a pretty snug fit, too. I was worried about it at first, but I have had no issues with this combo of parts after lots of banging away on the valves at gigs.

[bloke]

old-fashioned tall stop arms with the now-standard two sided hole cut down through the middle to fit a valve stem, but without any other specific shapes milled into it.

Imagine an old-style S-arm-receiving stop-arm without the slot cut in it for the stop arm, and without the hole drilled down through it for the stop arm attaching screw.

Personally, I really don’t care for their skeletonized stop arms, which require using that really tiny size of Minibal link (which they are using on all of their instruments, these days).
As much as Minibal links are abused when playing the tuba (by most players, because – unlike violinists – there is no emphasis on finger technique… ie. “wham - wham - wham”… and realize that I mostly do work for other people, and rarely for myself, so I have to consider what is most likely to hold up), I just like using the larger size links with a nice strong 3mm steel screws - as are used in the B&S factory). Of course, these won’t fit on the skeletonized Miraphone stop arms, but they’ll sure fit on top of the old-style stop arms.

[the elephant]

This is one of my favorite parts of building linkages. Absolutely delightful work! This is before I started using Minibal parts. I used some very nice RC car parts that are way superior to those ugly-assed Dubro parts, and I have never had one fail or require any sort of adjustment, even after 20 years of use. Great stuff! (The trimming of the stop arms was done freehand using my trusty Dremel and some files. Each one usually takes about an hour to convert. For this Cerveny, though, it took longer as the stop pins were all bent, too short, and one had broken loose. I had to make new ones. Again, very rewarding work.) Of course, I was not trying to turn a profit; these were for my own use, so I could afford the time needed to do this.

[bloke]

“Each one takes about an hour to convert.”

‘ very handsome indeed - and I’m sure that works quite well, but that’s also $500 of time (particularly now that countless additional trillions of hyperinflationary dollars have been printed, after intentionally bioweaponing us), in the “doing it for others and buying groceries with the remuneration” world.

Yeah… I threw in a bunch of stuff that doesn’t have anything to do with repairs, but it all absolutely has to do with what things cost and what we have to charge for things - as well as what we charge for segments of our lives - when doing labor.

When I first started doing this mess, $17.50 an hour would have been considered a workable wage. Today, that’s what they pay totally unskilled people to haul the garbage out the back door of Wendy’s.

I’m often still only paid about $40 an hour to rehearse and perform music with orchestras, (though one does pay me about twice that much). Particularly considering the commute time to any of those orchestras venues - as well as the draconian fuel expense - I must consider performing “for money”, now, to be a hobby.

[the elephant]

… that’s also $500 of time…

As I said, I do these for *me*, but I have also sold this service about 25 times over the years, and for a four-valved horn I charge about $450 + parts. (I move much faster when I have made a quote in order to not lose money, regardless of how worthless it may appear to be. It still pays for my house, food, cat stuff, and all my beauty aids and hair weaves.)

I still offer this service, but I don't charge a C-note per hour. I get about $85 per hour. You know how economically depressed Mississippi is, of course, heh, heh…

[bloke]

… that’s also $500 of time…

As I said, I do these for *me*, but I have also sold this service about 25 times over the years, and for a four-valved horn I charge about $450 + parts. (I move much faster when I have made a quote in order to not lose money, regardless of how worthless it may appear to be. It still pays for my house, food, cat stuff, and all my beauty aids and hair weaves.)

I still offer this service, but I don't charge a C-note per hour. I get about $85 per hour. You know how economically depressed Mississippi is, of course, heh, heh…

Some refer to places - where it is less expensive to live - as "economically depressed".
I - otoh - refer to them as "reasonable-cost" or "bargain-priced" places to live. Further, it's quite common for such places to offer their residents considerably more individual liberty, as well as (going along with "reasonable/bargain") much lower rates (even based on equal $$$$$$$ amounts of property, etc.) of taxation. No matter WHERE one lives, there are houses ranging from squalor to mansions, there is internet, there is USPS, FedEx, (if someone thinks they need it) cable-garbage, and (everywhere) there are really wonderful people, and (everywhere) there are turd-like people. Right where I am, my closest neighbor (I can barely see their house) started out as a turd, but (well...) Mrs. bloke just CONTINUED to "do her thing", and even that turd-guy finally came around - and is now a "nice guy".

My county is possibly (considering everything...and I've seen it listed nationally) THE LOWEST COST county in which to live in the nation.
I'm not going to reveal - here - how low my property taxes are, how little I pay for garbage service, how VERY LITTLE my county infringes on my natural rights, and (even though some stations are volunteer) how VERY FAST our fire department shows up, as I'm REALLY NOT interested in a whole bunch more people moving in here, jamming themselves into city-like subdivisions (as they do in ONE town in this county) and turning this place to $h!t. I am seeing (breaks in the tree lines) people moving here (seeking refuge from "blue" locales) and building "show places" (well out of sight - a thousand feet or more back off their road). I'm really not concerned about those people, because (unlike the people moving here from suburban Memphis and shoehorning themselves into new suburb-like subdivisions) those people building those showplaces carry their own weight, keep to themselves (much like a bloke), and don't demand that the rest of us pay to widen roads, hire more full-time policemen/firemen, and/or pay to build new schools/parks - for their convenience.

BACK TO THE ORIGINAL TOPIC:
my work, and its quality...

[the elephant]

Economically depressed means most jobs are minimum wage, most people do not go to college, jobs are scarce, even at McDonald's. It means that it is difficult to get good quality produce, meat, and sundry groceries if you don't have a car because there is zero public transit. It means that your gas is fifty cents a gallon more than in town, It means very high crime and lots of gunshots every day.

It does not mean "low cost of living" to anyone but the extremely out-of-touch who manage to say very insulting things without even understanding why it is insulting.

[bloke]

I’m more economically depressed than you are !!!

…but to point out the actual causes of economic depression results in a locked thread, doesn’t it?

I’m pretty sure that nearly everyone understood that I was criticizing the proletariat and bourgeoisie (assuming that their measly property taxes that that pay on their new subdivision houses - as well as their measly sales tax that they pay at the unwanted-by-most-in-this-county Walmart - are enough to cover the ACTUAL costs of them having moved their butts over here from maim-fuss - along with all of their children - who will avail themselves of the "free" schools and such), and not the destitute.

minimum wage:
My disabled son (whose most serious disability is denying that he his disabled) has been doing minimum wage jobs for the last decade.
Lately, I haven't seen any entry-level jobs that are offering less than $15 - $17/hr. That having been said, (though gov't and media offer comically lower inflation stats for our consumption) the pre-plandemic $7.50 is - just about - the new $15, n'est-ce pas?





https://tinyurl.com/2p9e9ds4

[bloke]

Here's something you don't see every day:

a hard case that ACTUALLY FITS a Miraphone 184 B-flat with a only a 14" bell, YET 39" tall...



bloke "Tomorrow's a big day: 5 errands / 600 miles / 11 - 12 hours"

[York-aholic]

Here's something you don't see every day:

a hard case that ACTUALLY FITS a Miraphone 184 B-flat with a only a 14" bell, YET 39" tall...



bloke "Tomorrow's a big day: 5 errands / 600 miles / 11 - 12 hours"

Glad you are feeling up to it and have a good trip.

[bloke]

Thank-you...
Honestly, I'm not certain that I am...but I'll have two riding shotgun - along with some "daytime" meds.

[Rick Denney]

And it fit just fine in the back of my Expedition, too.

Rick “hmmm” Denney

[bloke]

It seems as though 84 #2 project is completed (to a playable level) and gone.

[bloke]

This is an action shot of 84 #1 (which was the eBay-bought property of my customer/colleague, and which I brought back from the eBay graveyard).

I'm really glad to see this, because one rotor body was missing (lost in the mail, when I sent it to Miraphone to copy - apparently sent to Brazil ). I sent Miraphone measurements (rather than risking another rotor body in the mail). They made a complete new rotor body (might have even been rotor #1, which is sort-of an important one...I honestly can't remember which one...it was either #1 or #4) from measurements. I had to final fit it into the casing (at first, it wouldn't drop all the way in), and get it spinnin' good enough for someone to actually USE.

(Sometimes, stuff works GREAT in the repair shop, but - once at the home of an owner - problems may occasionally rear their ugly heads.)

I was reasonably convinced that it was "good", but the problem with this person is that they tend to put up with too much crap and never complain when something of theirs actually NEEDS to be better (ie. "too nice"). ...so its REALLY GOOD to see them PLAYING it, which means that it IS working - otherwise, they wouldn't be PLAYING it, would they?

[Rick Denney]

I don't have an action shot of me playing it, but I do have a couple of pics.

Joe and I talked about the valve linkages. To meet our meeting opportunity, he had collected bits at a hobby shop to cobble together minibal links, given his late discovery that the S links were unsalvageable. (He did give me the old S links.) The 3mm screws with nice round heads were great, but the washers weren't a great fit and therefore he couldn't crank down on them as much as he might have otherwise. So, they were just tight enough not to wiggle around but any tighter and the slightly oversized plastic damping washers would bind on the ball end. He secured them using a nylock nut in the clevis gap of the old-style stop arms, and spaced the ball end out enough to clear the stop-arm screw using thick washers made from cutting aluminum tubing. This was serviceable, but, as he predicted, needed a better fix.

He simply ran out of time to make it better, but then he knows me and knows I could deal with it.

He suggested, as you can read above, replacing the stop arms with the chunky style stop arms from Miraphone that put the ball at the same level as the stop-arm screw, rather than making the linkage wrap around the rotor bearing the way Wade has pictured it above. I may order those from Miraphone, but all in good time. In the meantime, I ordered some tight-fitting, narrow-pattern stainless steel washers from McMaster, along with tight-fitting plastic washers. By tight-fitting, I mean washers with inside diameters of 0.12", really designed for the standard looser fit on #4 wire but just big enough to fit over 3mm rod.

Here are the washers--the ones Joe could source locally to him at short notice are at the bottom, and the plastic damping washer is nearly outside the field of view. It's too big, and slid down over the ball too far when tightened too much.



Instead of the bits of tubing, I stacked washers under the ball end and used the plastic washer under the screw head. The plastic washer has a larger outside diameter, so the ball end will bump it before hitting the steel washers under the ball when the linkage wiggles side to side. I could crank down on the screw into the threaded bottom section of the stop arm without binding, and didn't need the nylock screw. I have some 1/8" stainless steel tubing I'll eventually cut into sections to cover the threads across the clevis gap.



Another approach would be to ream out the hold in the upper flange of the stop arm for that tubing, and use a longer piece of the tubing to extend from the lower (threaded) flange to the base of the ball, instead of the stack of washers. If the top flange is reamed for an interference fit and the tubing pressed into it, it will be a permanent construction. Even better would be to use a solid rod and then drill and tap a hole for the screw.

Another issue was that the fourth valve had been replaced at some point in the pre-bloke history of the instrument, but the replacement wasn't machined correctly to fit the thrust surfaces in the old casing. The bearing adjustment screw in the rear cap was used previously to take up the resulting 0.7mm of slack, but we all agree that is a temporary solution at best. Machining down the inside rim of the rear bearing plate might have taken up the slack (and there was already some machining done there) but the rotor would be misaligned--too close to the front of the casing. I blued up the valve and determined that it was still (barely) riding on the bearing thrust surface and not the outside of the valve, but based on arange of measurements using precision measurement tools that I'm always eager to play with, the rotor needed to be positioned further to the rear.

The proper fix, as Joe suggested to me, is to ask Miraphone to machine a new valve using one of the other valves as a model. But I'm impatient and sought an easier fix that didn't require shipping to and from Germany. Again from McMaster, I acquired a stock of brass shim washers in various thickness ranging from 0.1mm to 0.5mm, with a 6mm inside diameter. This was slightly too small to fit over the rotor shaft, and I knew I would have to ream them a bit to fit.



In the end, a single 0.5mm washer did the trick, taking up the fore-aft play in the valve. It did move the stem out of the front bearing by that amount, which meant the tapered bearing didn't fit quite as tightly. I'll swage down the bearing shell a bit to suck up that gap.

This is a low-grade fix, but it works, at least for now.

Joe purposely used hard bumpers on the return to expose any rattling issues, but I'll probably replace those with softer bumpers in the fullness of time.

Rick "fun with depth micrometers" Denney