TromboneChat

As an educational posting I would like to share some pictures I took of a CR rotor valve.  I used paint to label the individual parts for those of you who do not know the names of the various components of your trombone's valve system.

The names and decriptions given are in American English and do not often translate well to other languages.

I am open to editing if any you have informed additions to these diagrams.

I purposefully left out the description of the back bearing on the rotor.  Technically both the shafts on rotor valves are spindles, however the back bearing is often simply called the back bearing to differentiate it from the spindle bearing where the stop arms mount.

So rotors have two spindle shafts and two spindle bearings, but in common reference a spindle bearing is the area in which the stop arm and linkages mount up.

I might post pics of a standard rotor later in time, as a CR is a specialized higher end rotor with bent port construction within the rotor itself.  These means instead of being made out of a single chunk of brass (billet rotor) the CR valve's ports are made from bent tubing that is brazed into a rotor core.  These valves are also internally vented which most production valves are not.

I may continue this educational posting series covering different areas of the trombone.  It depends on my available free time (not much)

Hope some of you find this helpful,

Benn

THANK YOU SO MUCH!!!
most informative. I have never known the different parts until now. Thank you!!!

Good job, Benn

Thanks for the resource, Benn!

If you'd be so kind, could you discuss (since we have the picture), what "Tightening the Bearing Plate" entails?

That might be an interesting project if you find yourself with way too much time on your hands... talking about each part of the thing and semi-common repairs and maintenance that need to be done.

Book. Marked.

Quote from: octavposaune on Sep 01, 2012, 12:26PMAs an educational posting I would like to share some pictures I took of a CR rotor valve.  I used paint to label the individual parts for those of you who do not know the names of the various components of your trombone's valve system.
Benn
Hi Benn, can I post these pics on Italian Trombone Forum?
Thanks

Yes Baker go ahead and repost, 

There is no problem posting on the italian forum, but the names are obviously only in English.

The CR valves are available from Kanstul Musical instruments in Kits for retrofit.

You may also use any pictures I will post in the future of a standard Bach rotary valve. 

If I didn't intend to share these pictures I would not have posted them on the internet.

Benn

I'm going to "sticky" this so it stays at the top of the listing on this board.  Thanks, Benn.

Does Greenhoes look the same basically?

Quote from: Jox on Sep 01, 2012, 09:45PMDoes Greenhoes look the same basically?

If I remember correctly, yes. I have seen my Greenhoes apart several times. Didn't pay that much attention, but remember they were round like that with vents.

No CRs are not copies of Greenhoes,

If they were kanstul would have been sued.  Greenhoes have some rather interesting reliefs in the rotor that self vent without channels or ports.

For more information look at Greenhoes website and Kanstul also has a computer mock up showing some detail. I did not find necessary to post links for this thread (pics showing skeletonized rotor cores etc...)

Benn

Quote from: octavposaune on Sep 01, 2012, 06:08PMYes Baker go ahead and repost, 

There is no problem posting on the italian forum, but the names are obviously only in English.

The CR valves are available from Kanstul Musical instruments in Kits for retrofit.

You may also use any pictures I will post in the future of a standard Bach rotary valve. 

If I didn't intend to share these pictures I would not have posted them on the internet.

Benn
thanks, I'll try a translation 

The parts may look a little different, but what you see in the CR valve picture is also in a Bach rotor, an Olds rotor, a Conn rotor, etc.  Benn's point was to provide a common set of names so we can easily discuss issues we may be having with our particular horns.

Note that a Hagmann or a Thayer valve each have radically different parts and a disassembly picture of each might be useful as well.

Quote from: BGuttman on Sep 02, 2012, 05:40AMThe parts may look a little different, but what you see in the CR valve picture is also in a Bach rotor, an Olds rotor, a Conn rotor, etc.  Benn's point was to provide a common set of names so we can easily discuss issues we may be having with our particular horns.

Note that a Hagmann or a Thayer valve each have radically different parts and a disassembly picture of each might be useful as well.

Bruce, some of the Olds rotors were different, having internal stops and springs? A very interesting few hours were spent trying to work out a problem with one of their early independant double valve basses (P-24?) where a "repairer" had put the valves into the wrong casings!

Cheers

Stewbones

Possibly, but when I pulled my Olds Ambassodor rotor apart I had the same pile of parts that Benn showed for his CR Valve (and this was some 40+ years ago).

Hi all,

Bruce I would be happy to explain the differences between some of the various rotor designs, hence the genesis of this thread. I have on Olds rotor on display on my wall so I will take it apart and photograph it. The linkage system on Olds is unique as is the bumper system and internal spring.

I will probably explain the old style Bach and Holton ball and cup mechanical linkages, but that will have to wait until I have time (perhaps next weekend).

Benn

Nice job, Benn! Thanks!

OK everybody,

I had some time afterwork on Friday to take some quick shots of rotor sets.  An Olds P22 and a loose Bach tenor valve

I will start with the P22 and go from there.  At the end there will be a comparison of the P series rotor and a factory Bach rotor.  Even to the untrained eye the difference should be quite substantial

Benn

Now for the Bach Valve

And lastly,

2 pics with comparisons of the rotors.  Both valve rotors are made in the same manner, however the P22 rotor was made extra wide to accomodate a better, rounder internal port.  There is still a cutout on the top, but this rotor does not have an ovaled port like that of a factory Bach.

Speaking of ovaled ports there is a modern rotor that has ovaled ports.  The Rotax rotor have a purposefully oblong shape, but are far superior in performance to a stock Bach rotor.  These oblong port help minimize the size of the rotor casing.  Rotaxs are about the same physical size as a Bach rotor but have much more internal port cross section.

One other interesting aspect of Bach rotors is that the back bearing plate has a lip built into it.  This lip is what seals against the rotor casing.  No other manufacturer I have seen has this back bearing plate lip.

That is it for this week,

Benn

Quote from: BGuttman on Sep 02, 2012, 07:06AMPossibly, but when I pulled my Olds Ambassodor rotor apart I had the same pile of parts that Benn showed for his CR Valve (and this was some 40+ years ago).There was a period of time when the valves used on A-20's and R-20's had conventional stop plates and stop arms and lever-mounted springs; I suspect that they were sourcing the valves from another company for some reason.

There's been a lot of "variations on a theme" in rotor design through the years, but the fundamental concept is the same. You've got a rotor core with spindles, a casing, a cap, some sort of stop mechanism, and a spring. Benn's photos should be useful for just about anyone.

Benn,

Have you considered this with the Rotax valve?  I know of one you could use for reference.

This is totally random, but that's a Kanstul 1588CR, right? The Nickel Silver Slide tenon/receiver and 85/15 bell seem to say so, though it could be one of Kanstul's one offs.

Anyway, this is another great thread, and I wonder again why Bach has never addressed the issues that many find with their standard rotors and undersized goosenecks on their 42's. It's clear that even back then there were other makers who had addressed the issues of using better rotors, such as olds. It's dang shame olds ended up the way it did. They made great horns, something that a lot of people today are ignorant of. If it is a production horn and doesn't say King, Conn or Bach, it gets no credibility.

Quote from: daveyboy37 on Apr 05, 2013, 11:14AMAnyway, this is another great thread, and I wonder again why Bach has never addressed the issues that many find with their standard rotors and undersized goosenecks on their 42's.Because they're afraid that there'll be people who don't like the change. "Why did you do that? It doesn't play like a Bach any more!"

So could someone explain to me what the difference is between all of the "improved" rotor designs? 
For example, Greenhoe,  Rotax, Shires, and Kanstul?

Quote from: tombone21 on Apr 05, 2013, 03:32PMSo could someone explain to me what the difference is between all of the "improved" rotor designs? 
For example, Greenhoe,  Rotax, Shires, and Kanstul?

Each has their "trademark" designs.  We could tell ya but then we would have to...   

Quote from: tombone21 on Apr 05, 2013, 03:32PMSo could someone explain to me what the difference is between all of the "improved" rotor designs? 
For example, Greenhoe,  Rotax, Shires, and Kanstul?
there may be some threads around here on each individual valve. I don't know if there is a comparison thread, but when you see the actual rotors "unboxed" as it were, it's pretty easy to see the differences.  I don't think i've ever seen the a Greenhoe or Shires rotor core though.  The Kanstul is a bit different due to how it is constructed. the rotor core itself is made up of multiple pieces that are either soldered or brazed together. The Rotax is a lot like a standard unvented rotor, but the tolerances and geometry of the ports makes it a great valve.

Which of these would be the same or similar to my Conn 50H?  I want to take the valve apart and clean it, its getting sluggish.  I has a string linkage, I think its about a '70-ish.
Is this something I can do? I'm pretty adept at fixing things.  I've cleaned the valves on my dad's trumpet lots of times, but they're piston type, not rotary.

Yes, you can learn to take apart and put together a rotary valve.

There is a diagram on how to replace the string on the Osmun Brass Web Site.  It's for French Horn, but the technique is identical.

The key to success is putting the bearing plate back on.  It's easy to put it on slightly askew and the valve will bind.  I had a suggestion from Mirafone that worked great:

Place the bearing plate loose on the casing, aligning the notch on the edge with the notch in the threads.
Screw on the large valve cap until it's just finger tight.
With a light hammer (a wooden crab mallet works great for this) give the valve cap a tap.  You should now be able to turn it a little more.  Keep testing the rotor to make sure it turns freely as you do this.
Keep tapping and turning until the tap doesn't make a difference any more.

Good luck.

I reassemble a little different. I insert the bearing plate and line up the notches, but I don't put the cap back on. I grab a large socket from my socket wrench kit and hold it snug on top of the bearing plate. Tap tap tap with a rubber hammer on the socket and everything is true again. Spin the rotary valve just to make sure everything is ok and then I put the cap back on.

Thanks guys, I'll look up that site.  It appears that I need to remove the retaining screw in the stop plate and remove it first, in order to remove the rotor itself, with the rotor coming out the cap plate side.  Sound right?  I'm not sure where the return spring is, on the stop plate or the cap side, but
I'm sure that will become obvious. 
This reminds me of the first time I took a carburetor apart!  Go slow and be really careful not to force anything or lose anything!

Here's a site with a video.

http://hornmatters.com/2007/10/how-do-you-take-apart-a-rotary-valve/

A search on "Rotary Valve disassembly" yields a ton of sites.  Some more valid than others -- caveat emptor.

Just remember, if you try and fail, it's gonna cost a lot more to have the tech fix your boo-boo than if you brought it in first

Quote from: flyinblonde on Nov 04, 2013, 03:33PMThanks guys, I'll look up that site.  It appears that I need to remove the retaining screw in the stop plate and remove it first, in order to remove the rotor itself, with the rotor coming out the cap plate side.  Sound right?  I'm not sure where the return spring is, on the stop plate or the cap side, but
I'm sure that will become obvious. 
This reminds me of the first time I took a carburetor apart!  Go slow and be really careful not to force anything or lose anything!

Maybe you slipped and typed "stop plate" when you mean "stop arm."

Taking a valve apart is not difficult.  But the parts are quite precise, and brass is pretty soft stuff. Twisting a screwdriver between the stop arm and the bearing sleeve can work... but can nick the sleeve. Tapping the valve stem can mushroom the end of the stem (making it harder to reseat the stop arm on reassembly.)  Even if you get a proper brass punch to guide via the stop arm retainer screw hole, you can nick the thread. If you try the 'loosen the screw and tap on it' route you can break the screw inside the stem.

As long as you are keenly aware of places where your tapping and twisting can mis-shape things, you should be able to follow your mechanical aptitude.  But keep in mind, for instance, how much trouble you would be in if you broke the retaining screw off by tapping on it.  Do you have drill outs that small?

Quote from: LeoInFL on Nov 04, 2013, 01:54PMI reassemble a little different. I insert the bearing plate and line up the notches, but I don't put the cap back on. I grab a large socket from my socket wrench kit and hold it snug on top of the bearing plate. Tap tap tap with a rubber hammer on the socket and everything is true again. Spin the rotary valve just to make sure everything is ok and then I put the cap back on.

Pretty good idea Leo!  The gist of this is that the bearing goes on straight & seats true to the casing & rotor.
LIGHT tapping all around is a key to success!!!

Sometimes after you snug the cap,  you have to tap on the spindle to free the rotor if it doesn't spin freely.

NEVER pry against the spindle bearing when trying to remove the stop arm!!!!  NEVER NEVER NEVER!!!!!!!
Leave the bumper plate on & use that as the base for your pry tool to gently push off the stop arm.
I've found that those little paint can doodads from Homers place work well in most cases.

Eric

Just revisiting this thread while typing some instructions to another member and a question came to mind.

I wonder why the bearing plate under the cap is called the "BACK" bearing?  Seems to me that side of the rotor,  since it faces me all the time, would be the front.
And so,  that bearing plate, would simply be the "FRONT" bearing.

One other thing.

Benn,  if you can find a moment to modify these pics,  maybe point out the actual "bearing surface" of the stems?
Not an issue for the part on the bearing plate,  but more so near/under the stop arm.


Thanks!

Eric

FWIW, to me it makes sense that the side of the rotor that has the actuator lever and stop arm etc. would be the "front", which in turn makes the cap side the "back".

Just my take...

Yeah,  I thought about that.

Could go either way I guess.


Eric

I will have precisely zero time to update or add picture for a couple months.  If any of you havent noticed I havent been particularly active the last year and a half.  Life has been very busy but I see what you re saying Eric.

The back bearing plate is what American manufacturers have been calling it for many decades So that is what I call it.

The area where the stop arm, stop/cork plate reside has occassionally been called the spindle bearing, however this same term also applies to the back bearing as it is also a spindle bearing.

Eric were you referring to the internal thrust bearing on the "front bearing" in the casing and the rear thrust bearing on the back bearing plate?  I could detail those sometime in the future.  The ball bearing rotor I have has no thrust bearings, its suspended in place by careful machining.

I cant remember right now whether Greenhoes also got rid of the thrust bearing through double tapering both bearing or not.  Since they have a removable front and rear bearing plate that would be an option. 

Benn

I will have precisely zero time to update or add picture for a couple months.  If any of you havent noticed I havent been particularly active the last year and a half.  Life has been very busy but I see what you re saying Eric.

The back bearing plate is what American manufacturers have been calling it for many decades So that is what I call it.

The area where the stop arm, stop/cork plate reside has occassionally been called the spindle bearing, however this same term also applies to the back bearing as it is also a spindle bearing.

Eric were you referring to the internal thrust bearing on the "front bearing" in the casing and the rear thrust bearing on the back bearing plate?  I could detail those sometime in the future.  The ball bearing rotor I have has no thrust bearings, its suspended in place by careful machining.

I cant remember right now whether Greenhoes also got rid of the thrust bearing through double tapering both bearing or not.  Since they have a removable front and rear bearing plate that would be an option. 

Benn