Venting a Valve

[RBBERN01]

Hi everyone. I’m having a new rotor from Instrument Innovations put on my Conn 88H and my repair tech asked if I wanted the rotor vented. Since this is something I’m unfamiliar with I thought I would come here to ask opinions and to see if anyone has had this done before? I did some research online but found more things about trumpet and tuba than I did for trombone so I thought you all could tell me how it affects trombone specifically. Thanks!

[Burgerbob]

I don't think this would be necessary for the Olsen rotor.

[RBBERN01]

I don't think this would be necessary for the Olsen rotor.

Just out of curiosity since I don’t know, but what exactly does it do and why wouldn’t it be necessary for an Olsen rotor?

[Burgerbob]

It adds a way for the air to escape during transition between open and closed. This will cut down on valve pop or articulation when slurring though the valve.

[RBBERN01]

So is this not a big problem with the Olsen rotor? I haven’t played on it yet and am using it to replace an old busted rotor that came on my Conn.

[Burgerbob]

I personally don't think it would be necessary, and it would just be extra work and time and money.

[WGWTR180]

So is this not a big problem with the Olsen rotor? I haven’t played on it yet and am using it to replace an old busted rotor that came on my Conn.

You might want to start a thread "has anyone put an Olsen rotor on a Conn" especially if you've never played one.

[ithinknot]

There are two kinds of venting. The trumpet and tuba one is to release pressure in the valve loop so that on-the-fly slide pre-adjustments don't create a pressure differential that pops or blows back on the player when the valve is finally actuated.

This is irrelevant for a trombone valve, so you don't need it.

The second kind is intended to function as above:

It adds a way for the air to escape during transition between open and closed. This will cut down on valve pop or articulation when slurring though the valve.

... except that it doesn't, necessarily. It all depends on the valve and the implementation, but creating another 'in between' air route inevitably leads to a new and very possibly worse noise in the middle of the valve travel; the pressure fluctuation experienced by the player may be reduced (not that this was necessarily a huge problem to begin with), but the sonic disturbance will be changed in character in a way that is not necessarily 'better'. In any case, this is something that should be engineered into the design from the beginning rather than an excuse for a tech to drill out the rotor core. I haven't seen the core of an Olsen rotor, so I don't know whether the design features any of this sort of thing, but it was their choice, basically, not yours.

So, no.

(While we're here, does anyone have a photo of an Olsen core?)

[Burgerbob]

(While we're here, does anyone have a photo of an Olsen core?)

I should have one at home.

[Matt K]

I personally wouldn't do it to an Olsen rotor. I quite like mine the way they are; very smooth.

[hornbuilder]

I would be curious as to what, exactly, the tech is offering to do?

I agree with ithinknot.

[Burgerbob]

(While we're here, does anyone have a photo of an Olsen core?)

As far as I know, this is a production core.

[media]https://imgur.com/a/Yq1uUYt[/media]

[Crazy4Tbone86]

That particular photo does not show the three holes on the outside of the core, which is the other side of the "vent" system that is automatically built into the Olsen rotor. I'm with the others on this thread who say...."no, don't do it."

The design of the Olsen rotor is very good as it is. The website says "Our venting system releases at the half stroke," but it actually vents slightly before the half stroke because there is a little bit of width to those three holes on the outside of the core.

[Burgerbob]

Ahh, I remember now. I had the option of a vented core and a non-vented core- both were sent with the valve. This is the non-vented one.

[RBBERN01]

Thank you all for the info! Like I said earlier it was something I had never heard about so I wasn’t sure. My tech probably suggested it because his primary is tuba so he’s familiar with it. Thanks again!

[RBBERN01]

But since I have everyone here already, does anyone have a suggestion of a rotor oil that works best with the Olsen rotor? I have a few that I was going to experiment with but if someone else has already experimented for me I’ll take sone suggestions.

[Burgerbob]

Ultra-pure is my favorite with the Olsen valves and in general.

[Matt K]

I've been using hetman piston oil. Its my go-to for rotors that have tighter tolerances. IIRC its the same as the "thin" rotor oil, but in a different container.

[ithinknot]

Ahh, I remember now. I had the option of a vented core and a non-vented core- both were sent with the valve. This is the non-vented one.

That particular photo does not show the three holes on the outside of the core, which is the other side of the "vent" system that is automatically built into the Olsen rotor.

Thanks for the photos. It makes sense that they included the vertical 'chimneys' drilled through the core even on the non-vented version, as presumably these can also act as indexing points for machining the ports. (I assume the holes Brian mentions on the vented version are then drilled into the web between the ports and connect to these chimneys.)

[hornbuilder]

Those vertical "chimneys" were first used in the Greenhoe valve. They were there to allow the valve to be hand fit into the casing. A tool with prongs that fit into those holes was used to do that fitting. The holes are not "venting holes".

[Kbiggs]

Slightly off-topic… in my very limited experience and far-from-expert eyes…

From the two pics: a Greenhoe valve looks like it has more in common with Willson’s Cadex valve than a “traditional” rotory valve. It also looks vaguely similar to the old Kanstul CR valves except that the Kanstul had tubes held in place by an “exoskeleton” that formed the valve core.

The Olsen rotor, OTOH, looks like a traditional rotary valve.

[hornbuilder]

Your time lines are back to front. The Ghoe came on the market more than 20 years ago. Predating those other designs by a decade or more. Those other types came after, and they all owe aspects of their design to their predecesor.

[Crazy4Tbone86]

That makes sense concerning the construction of the Olsen valve…..hornbuilder and Ithinknot. The core needs those holes from the chimney to the outside diameter of the core for “venting” to occur. I think I have a spare Olsen rotor at home. If I can find it tonight, I’ll attach a photo that shows those holes. A picture is worth a thousand words.

BurgerBob’s photos are very interesting. I didn’t realize that Instrument Innovations offered a “non-vented” core on their rotors. I have never seen that before.

[hornbuilder]

Read my comment again. Those chimneys are not "vent holes".

The "venting" on a ghoe valve comes from the scalloped cut aways at the side of the rotor, that make an escape for the air when the valve is halfway activated. Colored black on this example to alleviate confusion of where I'm talking about.

[hornbuilder]

Here is a picture of the ghoe valve mid stroke. Without the side scallops, the web over the rotor port would block the majority of the casing port. That is where the idea of "venting" came from.

[ithinknot]

That makes sense concerning the construction of the Olsen valve…..hornbuilder and Ithinknot. The core needs those holes from the chimney to the outside diameter of the core for “venting” to occur. I think I have a spare Olsen rotor at home. If I can find it tonight, I’ll attach a photo that shows those holes.

Read my comment again. Those chimneys are not "vent holes".

The "venting" on a ghoe valve comes from the scalloped cut aways at the side of the rotor, that make an escape for the air when the valve is halfway activated.

I don't think there's any disagreement here

On the Greenhoe, the scallops provide the intermediate/vent path, and the chimneys are for fitting and irrelevant to the venting. (That fitting tool is a nice idea and must really help with maintaining close tolerances in lapping/fitting... and thanks for the photos!)

On the vented Olsen, rather than using scallops, those chimneys can form part of the vent path (holes in the webbing -> chimney -> across the top/bottom clearance -> chimney -> holes in the webbing), as well as perhaps being used in the fitting process in a similar fashion to the Greenhoe.

[Crazy4Tbone86]

Exactly as ithinknot is stating……there is no disagreement. On the Olsen valve (not the Greenhoe valve), the chimney itself does not serve as a vent. BurgerBob’s photos are an example of that. Thus, the reason Mike Olsen sells (or did sell at one point in time) that design as “non-vented.” It has the chimney for the tooling, but does not have the three holes.

On the Olsen valve with vents, the chimney becomes part of the vent because the three holes allow the air to leak into the valve casing port at the half stroke. If there is still confusion, the photo that I will attach tonight should make things clearer.

I am sorry that I cannot attach the photo right now. I am about to start a class with a dozen 5th-grade trombone-playing boys. If I turn around for a second, these guys will start sword fights with their slides. Talented kids….but wow, they are immature!

[Crazy4Tbone86]

I was able to find some Olsen Rotor parts tonight and have attached the photos below. Like I stated before, I have only seen the Instrument Innovations rotors that have the vents. The first photo shows the three vent holes that are on both sides of the core. The second photo shows that the vent holes are connected to the tooling chimneys.

I actually have a defective Olsen Rotor in which the brazed knuckle popped off the housing. Mike claims that he had a defective batch in which someone tried to rush the cooling process and the brazing bonds were not solid. When he found out I had one from that batch, he sent a new rotor to me and it arrived the next morning.....great customer service! Anyway, the cool thing about seeing it without the knuckle (third photo) is that the venting actually happens earlier than at 45 degree rotation. We must take into consideration the width of the knuckle tubing, but I would estimate that venting starts at about a 38-40 degree rotation.

I plan to braze that knuckle (or a different knuckle) back on someday. I figure that I will hold on to that valve and use it when I need a valve with a unique knuckle direction.

Back to the original post....I highly recommend the Olsen rotors. Everyone that I know who plays a Bach 42 with an Olsen rotor conversion, loves it! Strangely, I do not know of anyone who has converted a Conn 88H to Olsen rotors.....but I think it would be equally successful. Finally, there is NO NEED for your tech to do any additional venting. The design of the vented Olsen rotor is great the way it is.

https://trombonechat.com/download/file. ... d=12030ind some spare Olsen rotary valve partshtthttps://trombonechat.com/download/file.php?mode=view&id=12032ps://trombonechat.com/download/file.php?mode=vihttps://trombonechat.com/download/file.php?mode=view&id=12035ew&idhttps://trombonechat.https://trombonechat.com/download/file. ... 2036=12031 in my shop.

[Kbiggs]

Your time lines are back to front. The Ghoe came on the market more than 20 years ago. Predating those other designs by a decade or more. Those other types came after, and they all owe aspects of their design to their predecesor.

Yeah, I wrote that backwards, didn’t I?

[TheBoneRanger]

I’m enjoying seeing the cores of these valves! Interesting to see how each manufacturer goes about it. Maybe we should have a thread of just valve cores.

Is the Greenhoe core unusual for a rotary, in that it has more of a “tunnel” through the core? (I’m sure that’s not the terminology)

While we’re at it, here’s the inside of a Meinlschmidt on a Bach Centennial:



Andrew

[LIBrassCo]

Here's one a bit different from the rest. Willson Caidex core.

[Dsbones]

Here's one a bit different from the rest. Willson Caidex core.

What’s with the seam/milling line?….in the middle of the inner?

[LIBrassCo]

Here's one a bit different from the rest. Willson Caidex core.

What’s with the seam/milling line?….in the middle of the inner?

It was machined internally from both sides, and that would be where they went to. No mistmatch in the part, just visually obvious.

[timothy42b]

Here's one a bit different from the rest. Willson Caidex core.

What’s with the seam/milling line?….in the middle of the inner?

That Caidex is very intriguing. The designer sent me a brochure explaining the details and it seemed to make a great deal of sense. A few years back I doubt if we'd have had the machining equipment to make it accurately.

[LIBrassCo]

What’s with the seam/milling line?….in the middle of the inner?

That Caidex is very intriguing. The designer sent me a brochure explaining the details and it seemed to make a great deal of sense. A few years back I doubt if we'd have had the machining equipment to make it accurately.

Its not the ideal machine but any 5 axis mill can do it. I'd ideally want something like an 8 axis swiss turning machine with a sub spindle. The tech has been around for a little bit, but they've improved greatly (particularly on the software side).

Theres a few changes I'd like to see in the valve, but i doubt my opinion matters enough to anyone to have them materialize.

[Bonearzt]

I’m enjoying seeing the cores of these valves! Interesting to see how each manufacturer goes about it. Maybe we should have a thread of just valve cores.
Is the Greenhoe core unusual for a rotary, in that it has more of a “tunnel” through the core? (I’m sure that’s not the terminology)
While we’re at it, here’s the inside of a Meinlschmidt on a Bach Centennial:

Andrew

The basic function of ALL of these "new" valves is a consistent bore through the valve.
A thought process that Mr. Ed Thayer started with his design of the original "axial flow" valves.

The addition of the "venting" is a step above that in trying the make the valve transition as smooth as possible.

The "Cadex" valve is designed to have the least amount of bore constriction/deflection through the valve body as possible. And is described in detail in a report I was provided with, which I'll have to dig up...

Not sure how this all translates between air flow and sound wave flow, that's WAY above my pay grade!!
But it would be interesting to see an actual, in-depth study of the sound wave and how it interacts with the valve section tubing in comparison with how the air flow interacts!
NOT the same I don't believe.....



Eric

[Bonearzt]

Here's one a bit different from the rest. Willson Caidex core.

What’s with the seam/milling line?….in the middle of the inner?

That has my attention too....I would think there would be NO such transition "line" if machined accurately.

[Elow]

Has any brand attempted to keep the taper from the gooseneck consistent even with valves? Instead of being just a straight .562 have the open side of the horn tapered like it would be with a straight gooseneck.

[Matt K]

Has any brand attempted to keep the taper from the gooseneck consistent even with valves? Instead of being just a straight .562 have the open side of the horn tapered like it would be with a straight gooseneck.

My understanding is that's sort-of what the Shires dual-bore rotor does. I don't know if its tapered inside the rotor core, but the exit ports are different sizes. I'm thinking about having mine cut to G and they told me that I wouldn't have any problems because the tubing is the same up to the point where it goes back into the rotor, but after that point it gets bigger.

Hagmanns also have a "progressive" bore option which my understanding is similar but also might not be exactly a taper like you would find in a gooseneck.

[Burgerbob]

There are progressive bore valves from Hagman.

[LIBrassCo]

What’s with the seam/milling line?….in the middle of the inner?

That has my attention too....I would think there would be NO such transition "line" if machined accurately.

Even with a perfect match machining from both sides theres going to be machining marks like this. Theres no step or ridge, just the pattern from the end mill used.

[Bonearzt]

That has my attention too....I would think there would be NO such transition "line" if machined accurately.

Even with a perfect match machining from both sides theres going to be machining marks like this. Theres no step or ridge, just the pattern from the end mill used.

Gotcha

[jonathanharker]

Does anyone know if these core types have patents, or design marks on them? Asking for a friend. Actually not really, I'm just a giant nerd and I want to update the trombone articles on Wikipedia

I've managed to find a few patents with the usual US, EU and WIPO search tools: Thayer, Greenhoe, Conn CL2000, Selmer "K" valve (named after the inventor, Herbert Kirts), Shires Trubore, and the Tétreault valve (US 9153216 issued 2015; anyone seen one of these in the wild?)

However, I have so far failed to come up with many others, like the Hagmann valve (as far as I've been able to tell, it is some sort of design trademark rather than a patent) and some of these newer vented designs. I love the pair of dependent Greenhoes on my (1999) Shires bass.

[BoNeLife]

I would love to see and m and w valve rotor! That would be cool if someone had pics.