Thayer Valve Section and new Handslide on Bach 42

[BassBoneWaluigi]

Asking for a friend,
He owns a corporation-era Bach 42 with a closed wrap rotor that he is hoping to modify with axials and possibly a new slide. What brands would ya'll reccomend for this situation?

[BassBoneWaluigi]

He would also be open to other "improved" or oversized rotors

[Burgerbob]

You can buy the valve, wrap parts, and lever from Instrument Innovations, then find a suitable tech to assemble it.

As for slide, I recommend an Edwards TBCN as a great improvement for the average 42.

[BassBoneWaluigi]

You can buy the valve, wrap parts, and lever from Instrument Innovations, then find a suitable tech to assemble it.

As for slide, I recommend an Edwards TBCN as a great improvement for the average 42.

If he bought the Olsen improves rotor, would he need new tubing as well?

[BassBoneWaluigi]

Like a new wrap?

[Burgerbob]

You can buy the valve, wrap parts, and lever from Instrument Innovations, then find a suitable tech to assemble it.

As for slide, I recommend an Edwards TBCN as a great improvement for the average 42.

If he bought the Olsen improves rotor, would he need new tubing as well?

Not as much, no, you can make the old closed wrap work with the Olsen rotor. It does take some serious work by the tech to re-space everything to fit but I don't think it needs many new parts.

[Blabberbucket]

You can reuse all tubing except for the neckpipe which they would need to buy from Olsen as well, due to a slightly different knuckle alignment. The short 90 will need to be modified to fit the oversized valve like the attached pictures.

You will want a technician that has experience with this sort of work.

[Crazy4Tbone86]

I’m glad David Paul brought attention to that portion of the modification. The switch from standard 42 rotor to a traditional wrap Olsen rotor is very crowded in that 90 degree bend that David mentioned. I usually insert a small 25-30 degree bend coming directly out of the valve and then attach it to a sharper 90 degree bend (some UMI, Conn Selmer parts work for that).

It is not a simple plug-in-the-valve modification. It requires a little know-how to make it a tension-free F-attachment with clean connections.

[Matt K]

Fortunatley, tubing isn't particularly expensive, I would not necessarily limit my wrap choice to trying to coerce existing set of tubing into working w/ the upgrade. Although the proposed fix should work no problem, for not much extra expense you could probably easily get the same wrap as an 88HNV. Now... you might not WANT that wrap. Which is an entirely different consideration.

[jacobgarchik]

What does the rotor swap typically cost including parts and labor, assuming you keep the wrap?

[Burgerbob]

I'd assume something like $1k+

[brassmedic]

I wonder if it wouldn't work to remove the small bell braces and move the entire F wrap closer to the bell. Then you would make room for the larger valve without cutting a bend in half. And you could trim the end of the compound bend piece where it inserts into the valve slide outer to accommodate the wider knuckle spacing. Also, the extra long knuckles on the Olsen valve can easily be trimmed so as not to take up so much real estate.

BachF.jpg

[Matt K]

You could also potentially rotate the valve so that the front of the bracing is a little "behind" the bell. Kind of like how Getzen does it:

1036-lg.jpg

[Matt K]

What does the rotor swap typically cost, including parts and labor, assuming you keep the wrap?

"It depends." If you're talking about a true drop-in replacement, it is much cheaper. As little as a few hundred. There are a few costs that people don't consider that really add up. Linkages are pretty tricky and can double the cost! And if it isn't a "drop in" replacement, you'll probably need to at least modify if not get new linkages. There's also a lot of alignment that needs to occur and a lot of techs charge by the solder point. So a closed wrap could be more expensive to add to, maybe more than getting new, open wrap tubing with fewer solder points.

The range I'd say could be anywhere from $250 maybe $300 on the extreme cheap end of a "I got a new rotor that is identical to the prior one" to upwards of $2000+ if you want to do say, a Hagmann conversion.

[BassBoneWaluigi]

Thank you all for the help! He's probably gonna hold off on modification for a while, so we'll see what happens.

[hornbuilder]

There is no such thing as a "drop in replacement".

Anywhere, ever.

Using old parts involves "more" time than starting with new parts made specifically for that wrap.

You get what you pay for.

If I was looking to undertake the project described by the OP (and didn't do what I do) I would buy a complete section from Shires and mount the Bach bell on it. That way you're basically guaranteed of the outcome being good.

[Crazy4Tbone86]

There is no such thing as a "drop in replacement".

Anywhere, ever.

Using old parts involves "more" time than starting with new parts made specifically for that wrap.

You get what you pay for.

What Matt says is absolute correct. Just did a Bach 42 rebuild with an Olsen valve in traditional wrap. While it is nice to have the parts from the old wrap, I always take the whole bell section apart and reassemble it to fit the dimensions of the new valve. You save money by using a lot of parts from the old wrap, but it is definitely more labor and time than just using brand new parts. Even that statement is over-simplified because pulling an old F-attachment section apart usually includes some level of dent removal.

[jacobgarchik]

as an aside, interesting that closed wrap 42s, albeit souped-up ones, are coming back in style. You wouldn't be caught dead with one from 1990-2020 or so. (lol I've used mine that whole time).

[Elow]

My 42 has a Rotax, close to the size of the original rotor. Rotax is on my rebuilt Mt. Vernon, on the left is a Marston valve section off a slightly newer corp 42

[Matt K]

When I said "drop in" I meant more along the lines of identical OEM parts. Surely there are some manufacturers that have the same model valve available which would have the same dimensions as something with an identical model? E.g. with Yamaha, I'm pretty sure the rotor dimensions on their 500 series models haven't changed in 30 years.

[hornbuilder]

Dave Paul,
Next time you do one of these conversions, try the Conn 88H double bend crook. Available from Allied, C-49637-2. I don't know who "designed" the Bach part, but they barely made a useable part, IMO. The Conn part, however, works very well in this application.

[hornbuilder]

When I said "drop in" I meant more along the lines of identical OEM parts. Surely there are some manufacturers that have the same model valve available which would have the same dimensions as something with an identical model? E.g. with Yamaha, I'm pretty sure the rotor dimensions on their 500 series models haven't changed in 30 years.

Again. Nothing is a drop in replacement. Nothing is ever identical. Unless you're happy to have gaps underneath the ferrules. I think you would be surprised by the number of instruments that do have substantial gaps between parts underneath ferrules.

[Matt K]

The process described below for the Olsen valve seemed to be much more involved than adjusting for gaps under the ferrules. Are manufacturing variances really so common that you might expect to need to rebuild all of the tubing even on identical model instruments?

[hornbuilder]

Yes.

If you want it done right.

[Elow]

Matthew holds higher standards than most in the business… your local band repair shop isn’t going to go that in depth.

[spencercarran]

close to the size of the original rotor.

Horseshoes, hand grenades, and occasionally trombones

[Matt K]

Wow. Just seems wild to me that nobody can get parts to reliably be at least the same shape. I would expect that you could get a part for a certain model and, with minimal trimming, be able to put it into a horn if the same model. What is a common manufacturing tolerance for such bends? Like 1cm?

[Crazy4Tbone86]

Matthew holds higher standards than most in the business… your local band repair shop isn’t going to go that in depth.

Speak for yourself. I always try to make things line up perfectly under those ferrules. When working with used parts, it is not always possible, but the intent is always there in my shop.

I learned the skill from Todd Clontz. He showed me how he assembled horns when he built my first custom horn in the early 1990s. The horn played spectacularly, so that detail made an impression on me.

[Elow]

Speak for yourself. I always try to make things line up perfectly under those ferrules. When working with used parts, it is not always possible, but the intent is always there in my shop.

Yes, i would say you are in the group of techs who understand the importance. I was referring to shops where the main objective is to pump out school repairs as fast as possible. I would say your group of thinking is majorly outnumbered.

[hornbuilder]

Wow. Just seems wild to me that nobody can get parts to reliably be at least the same shape. I would expect that you could get a part for a certain model and, with minimal trimming, be able to put it into a horn if the same model. What is a common manufacturing tolerance for such bends? Like 1cm?

There is just too much to get through in this comment...

[Crazy4Tbone86]

Speak for yourself. I always try to make things line up perfectly under those ferrules. When working with used parts, it is not always possible, but the intent is always there in my shop.

Yes, i would say you are in the group of techs who understand the importance. I was referring to shops where the main objective is to pump out school repairs as fast as possible. I would say your group of thinking is majorly outnumbered.

You are referring to “play condition” repair work, which is the vast majority of the instrument repair business. I worked in a shop that did that with hundreds of instruments per day. Broken down, the business model centers around making an instrument comfortably playable by the hypothetical “average high school player” in the shortest amount of time. If you have techs who can do accurate triage and then quick repairs, your business can make money.

The thing we must remember is that there are technicians who do “play condition” repair work who are completely capable of building custom horns with exact connections under ferrules, tension-free horns, etc……, however they do not work in a shop that builds high end custom horns.

Different shops use different business models. There is a need for the play condition shop and the every-detail custom shop. The consumer makes a choice based on knowledge and/or their concern for those details.

[tbonesullivan]

Jeez. The only thing that will truly be a "drop in replacement" is something specifically designed to be a "drop in replacement", like a mouthpiece, air filter, etc. Trombone valves are, in most cases, not designed that way. I don't even think the cores to the highest tolerance rotors out there are immune to this. Recently they have figured out a way around this, but up until not to long ago even car engines needed break-in time while the bearing surfaces, rings, etc polished and honed themselves.

[hornbuilder]

To slightly scratch the surface of "tolerance definition" in the industry.

I build a handslide to an acceptable tolerance of +.003". That means the allowable difference in span between top and bottom of the handslide is between 0.0" and .003". So my slides sit within a range of .003"

Keep in mind a regular piece of writing paper is .005".

Another well known shop I know has an allowable tolerance of +/-.005". So, their slides can sit within a range of .010".

There is another very well known big shop (that I have not worked at) that build their handslide assemblies on jigs, (yes, this includes their top of the line pro horns) but do not check parallel after assembly. I have measured slides from this maker at .035" out of parallel. That slide was sold to a customer, and was within their acceptable degree of variance.

[Elow]

This has turned into a very cool discussion. Is the variance caused by the heat expansion of any importance? I wish M&W were at ITF, all this talk makes me really want to play one.

[ithinknot]

Is the variance caused by the heat expansion of any importance?

How would it not be...?

At a certain production rate and/or employee skill level, jigs are the answer... but above a certain tolerance they can't be the whole answer. Then, above a certain skill level, the difference is time.

[hornbuilder]

Sometimes the question even comes down to "does the tech even have an understanding of the impact of heat".

Jigs are not the be-all, end-all. They are a starting point. But again, it depends on what the end goal is. A part that fits the jig? Or a part that is parallel? (Thinking tuning slide assemblies here)

[tbonesullivan]

There is another very well known big shop (that I have not worked at) that build their handslide assemblies on jigs, (yes, this includes their top of the line pro horns) but do not check parallel after assembly. I have measured slides from this maker at .035" out of parallel. That slide was sold to a customer, and was within their acceptable degree of variance.

This would be the "fixtured" assembly I see referred to at some times, contrasting to the "non-fixtured" assembly of slides?

But, I think the "not checking" after assembly is always the more important part. I wonder what percentage of those fixtured slides come out warped, as I have definitely found many from a certain manufacturer.

[Crazy4Tbone86]

I was taught (again, I must give Todd Clontz credit for this) that the majority of solder joints “pop in” about .005 to .011 inch when they cool. Thus, I try to set up my inner and outer slides about .007 or .008 too wide when soldering and hope that they “pop in” at the critical split second when the solder cools to a solid. The problem is that it is not an exact science and every solder joint has a personality of its own. Some joints don’t “pop” at all. Some “pop” outward.

Many solder joints take multiple attempts to get the alignment perfect. Some are so stubborn that they require me to completely clean the parts and start from scratch. However, I do believe this attention to detail makes a tremendous difference to the discerning player.

Case in point…..I just purchased a used .547 - .562 dual bore Bach 42/50 slide from a guy who custom ordered it from (at that time) Bach/Selmer in the late 1990s. It is in silver plate and is immaculate because he claims he only used one it for a few hours and then stored it. As perfect as this slide first appeared, I discovered two flaws in its construction: the top of the outer slide is about .010 more narrow than the bottom. 2. The inner slide is about .008 more narrow than the outer slide . In other words, the inner slide will need to be adjusted outward about .018 after the outer slide is aligned.

My assumption is that these problems are the result of not taking the solder “pop” into consideration. It doesn’t matter if it is assembled in a jig or freehand. Setting up parts that are perfectly aligned prior to soldering will usually result in a misaligned slides, tuning slides , etc…

[hornbuilder]

It isn't the solder "pop", whatever that is. It is the fact that solder hardens before the cross brace tube comes back to its original dimension. Same thing applies to bell cross brace tubes and braces.

[Crazy4Tbone86]

It isn't the solder "pop", whatever that is. It is the fact that solder hardens before the cross brace tube comes back to its original dimension. Same thing applies to bell cross brace tubes and braces.

That’s interesting. Are you saying that the tubes or ferrule tubes expand with heat and then contract when they cool……but, the tubes contract AFTER the solder hardens? If so, that explains things in a different (and very logical) way.

The way it was explained to me is that solder has a “gel” or semisolid state at a certain temperature….think about the form that solder is in when you can swab it, but it is not quite hot enough to flow. As the solder cools it appears to be solid, but it is not quite hardened. However, it shrinks or shifts a little bit later as the “gel” hardens into the true solid form. One of the reasons why it pops inward is because the air in the brace tube contracts as it cools. That is the way it has been explained to me by a couple of techs (not Todd Clontz, these guys worked at a different shop). Not saying that it is fact, but it has seemed to be the best explanation up to this point.

Matt, I like your explanation. It seems very logical that the metal would expand as well with the air pocket and everything would shift inward as it cools, even after the solder has hardened. Whatever the explanation is, the phenomenon does impact how an instrument should be constructed. If an instrument maker does not account for it, there will probably to be alignment issues.

However, this brings up an entirely new topic…..Why doesn’t the expansion and contraction of brace tube solder joint end up with a neutral result. One would think that a brace (done in a jig or done freehand) would expand outward a certain distance and then contract inward the SAME distance. But it doesn’t…….most of the time the solder joint moves inward when all is done.

It was also mentioned on this thread that some makers don’t measure their work after they have soldered. That seems like a costly shortcut. This is phrase that has stuck with me: BEFORE you cut, measure it 3 times. AFTER you solder, measure it 10 times.

[hornbuilder]

The air expansion/contraction inside a brace tube is negligible. If it were as extreme as some say it is, it would suck the solder out of the joint into the assembly, which it doesn't do. Besides that, the metal coming back to its original dimension is going to have considerably more energy involved, than the air inside the tube. Air can compress, metal can't in this scenario, and would easily compress the air inside.

It does not end in a neutral result because the solder hardens "before" the tube has cooled back down to its original length.

[BGuttman]

Solder melts or freezes around 400 F (200 or so C; leaded a little less, lead free a little more). This is still quite a ways from room temperature and the metal has some adjusting to do as it changes to room temperature.

Electron micrographs I've seen of solder indicate that it is not uniform, but comprised of little "cells" probably of different percentages of tin and whatever else is there. It's probable that these cells can move past each other (explaining the "gel" effect).

I admire how you can find ways to compensate for this behavior to make the resulting joint relatively stress free.

[ithinknot]

Are you saying that the tubes or ferrule tubes expand with heat and then contract when they cool……but, the tubes contract AFTER the solder hardens?

Let's put it this way... the solder cools below the flow state within a few seconds, and below the gel/"smear but not flow" state shortly thereafter. If at this point you grab the part, passing dogs will be attracted by the smell of freshly cooked human flesh. The part is still considerably larger than it will be at room temp, but your hand is slightly smaller.

Agree about the guesstimated overshoot margin for average brace-type stuff - in my (admittedly very limited) experience doing this sort of thing, a locked caliper at around final+.008" seems to be a good starting point for an impromptu jig/stop.

It does not end in a neutral result because the solder hardens "before" the tube has cooled back down to its original length.

[hornbuilder]

I admire how you can find ways to compensate for this behavior to make the resulting joint relatively stress free.

In my early days of futzing with horns, there was considerable head scratching and frustration as to why I always had gaps on detachable bell cross braces. It wasn't until I actually gave some thought as to the effect of heat on materials that I began to understand why.

[Crazy4Tbone86]

My frustration was with inner slides. I would get both sides perfectly centered in the outer slide tubes and then they would always end up several thousandths too narrow when I checked them several minutes after soldering. Completely bewildered, I forced my eyelids not to blink and watched one as it cooled for about 40-50 seconds. That’s when I actually saw the brace shift inward.

I didn’t see the brace itself move, but I saw one side on the inner slide move from being perfectly centered to being more towards the inside of the outer tube. It freaked me out. That’s also when I started asking questions!