How do you screw your bell?

[BigBadandBass]

Hey all, quick question, I just got a screwbell for my shires bass and am unsure how to grip the flare when I take it off. Should I grip around the stem and twist or near the flare where there’s more torque? I’m worried that I’m going to twist/damage the flare if I twist too hard in the wrong spot. Also, how tight should I be screwing it in? Thanks y’all

[BGuttman]

My French Horn friends put their hand in the flare and screw that way. Don't use a lot of torque -- you can easily cross-thread the bell and then you are in deep trouble.

How tight? So it won't fall off.

[Matt K]

I turn mine upside down in between my legs and unscrew the top without doing much to hold onto the bell so as to avoid putting too much pressure on it.

[TromboneSam]

I hold the stem “threads-up” close to the top in my right hand, and hold the flare with four fingers inside and thumb outside. I gently screw it in, and if I can’t get it to thread gently the first couple times I screw it backward until it falls and kind of “sets” into the threads. Then I tighten the rest of the way with my left hand in the same position.

[Burgerbob]

I spin up the flare as fast as I can and throw it straight up in the air. I position the stem below it and catch it perfectly on the threads. Before it overtightens, I stop it lightly with two fingers. Then I jam it on as hard as I can, just in case... You never know.

[BGuttman]

I spin up the flare as fast as I can and throw it straight up in the air. I position the stem below it and catch it perfectly on the threads. Before it overtightens, I stop it lightly with two fingers. Then I jam it on as hard as I can, just in case... You never know.

Show-off!

[boneagain]

Hey all, quick question, I just got a screwbell for my shires bass and am unsure how to grip the flare when I take it off. Should I grip around the stem and twist or near the flare where there’s more torque? I’m worried that I’m going to twist/damage the flare if I twist too hard in the wrong spot. Also, how tight should I be screwing it in? Thanks y’all

I see some fun responses, in addition to the helpful one from Bruce.

I'll expand on what Bruce wrote, based on experience working for George McCracken, who has done more horn and trombone screw-bell conversions than I can count. Oh, and who has repaired the results of more screw-bell disasters than I thought were possible.

Directly from your question, regarding torque: torque is your enemy!!!

It is unlikely you will twist the flare, but more than one player has twisted the TAIL leading into the flare trying to remove an over-tightened screw-bell. Horn players have a hard time holding the bell by the tail for bell assembly. Even a double-rotor base can hold by the tail though.

Why hold by the tail? Two reasons: torque and touch. Gripping around the tail will not let you apply as much torque as gripping by the valve section. As you apply the torque, your hand on the tail will be more sensitive to the torque than the hand with the bell.

This also is a factor in why Bruce's friends put a hand INSIDE the flare for installation. This gives less leverage for overtorquing the bell. This ALSO gives a much finer feel for any cross-threading.

One trick I use for avoiding cross-threading is to start install with an UNscrewing motion. This less my fingers feel where the two thread-ends clunk into matching. If you push hard while doing this you can damage those ends, so don't push hard. Just feel for the engagement point, THEN start the clockwise install.

As far as "how tight?" Toss the word "tight" out entirely. Substitute "snug." And go for snug enough to NOT buzz. If the ring was made and installed properly, snug will allow any longitudinal vibration that can make it past the mass of the ring to keep on down the flare. Snug MAY still lock up on you, but is FAR less likely to stick than "tight." And if you can't remove the bell after "tightening" it, do NOT just stick the bell section between your legs and wrench on it. The resulting wrinkles are a bear to iron out, and can even total a bell taper. Yeah, the horn is hard to bring home in the flat case when the bell is still on. But it's just as hard to bring home if the bell CAN'T come off and you've wracked the bell tail!

So, think 'snug'.

After you've had it a while you'll get a feel. You may even ask yourself why you even asked the question. Some of the more entertaining answers seem to be in that vein.

But until you get there, this is a good question. Some consideration now will stand you in good stead when you assemble the thing automatically later on, and do NOT get any crossed threads or over-torquing damage!

DIfferent screw-bell topic: have you tried some side-by-side comparisons with your plain versus screw-bell horns? I found the feedback behind the bell to be quite different, and the volume capacity (before the ripping-sheet-metal level) to be notably higher on the screw-bell. That required some careful recalibration of my ear and playing system to avoid getting "the hand" all the time. YMMV.

Enjoy the compact-carry and sound changes!!

Dave

PS: I sure wish I could see a Youtube of Aidan's method!!!!

[OneTon]

I spin up the flare as fast as I can and throw it straight up in the air. I position the stem below it and catch it perfectly on the threads. Before it overtightens, I stop it lightly with two fingers. Then I jam it on as hard as I can, just in case... You never know.

Monks have only to take a vow of poverty. As fate would have it, trombone players must apprentice in a pizza parlor.

[asmith]

I spin up the flare as fast as I can and throw it straight up in the air. I position the stem below it and catch it perfectly on the threads. Before it overtightens, I stop it lightly with two fingers. Then I jam it on as hard as I can, just in case... You never know.

Monks have only to take a vow of poverty. As fate would have it, trombone players must apprentice in a pizza parlor.

Only a true master can go behind the back. You know Globetrotters style.

[BigBadandBass]

DIfferent screw-bell topic: have you tried some side-by-side comparisons with your plain versus screw-bell horns? I found the feedback behind the bell to be quite different, and the volume capacity (before the ripping-sheet-metal level) to be notably higher on the screw-bell. That required some careful recalibration of my ear and playing system to avoid getting "the hand" all the time. YMMV.

Yes actually! I switched from a Bollinger bell to a shires BIIY in the standard weight with a Horn ring. It’a a different feel, if anything it’s a different response and the sound doesn’t break up nearly as early for me too, that’s probably the weight, the bell is heavy. I have yet to get the hand, but I also entered grad school this semester being told that I was “one of the quietest bass trombonists out there” so maybe having a raised noise floor is a good thing.

Also thank you all for the advice, the inverse screw is a great idea! I’ve been doing that and the process is much smoother, do any of y’all oil the threads or no?

[Burgerbob]

I oil my threads.

[Matt K]

I use dry graphite lube, personally

[elmsandr]

...
DIfferent screw-bell topic: have you tried some side-by-side comparisons with your plain versus screw-bell horns? I found the feedback behind the bell to be quite different, and the volume capacity (before the ripping-sheet-metal level) to be notably higher on the screw-bell. That required some careful recalibration of my ear and playing system to avoid getting "the hand" all the time. YMMV.
...

I don't have a side by side.. my current screw flare is a Holton flare that was NOS when they moved out of Wisconsin. It is on a Frankenbass that is mostly Bach. I liked it enough that I have a screw fitting for one of my Bach flares, but that flare is hilariously out of round where the fitting would sit. Like 1/4"+ out.

Back to this question, this flare on the current chassis and the previous Edwards that I had it mounted to for a couple of years does have the ability to get away from me a bit... The feedback is good, though definitely different that the non screw bells, but I like it. The ability for some... over excitement, perhaps on the top end leads me to getting some feedback/hand.

To make sure I am clear, I am happy with the sound and feedback, and have been dancing around, but probably will put a screw fitting on at least one, if not several of my vintage flares. It is just too convenient and I find the effects to be beneficial enough to not be concerned about it (though I hate to make irreversible changes).

To the main topic, I do occasionally lube them. I've used my rotor linkage oil. Mainly because it was what I had in my hand. Be careful with lube... the effect there is that for the same torque on the threads, you get a much increased clamp load in the joint. You are lowering the dynamic friction as the parts move against each other. That is, when it is lubed, for the same effort, you are tightening the flare on more if you have lubricated threads. Could lead to it being difficult to separate if you aren't paying attention.

Cheers,
Andy

[boneagain]

Andy,

Have you experimented between "just barely snug enough to not rattle" and the fine torque adustment of "gutentite?"

I ask because, like you and Aidan, I DO oil the threads. This avoids both corrosion and galling, but adds the over-torquing risk you mention.

I can hear no difference behind the bell or in recordings between the two torque specifiications above.

If you have the same experience, would you recommend the just barely snug enough?

In all the years I've seen threaded Horn bells I have YET to see even ONE spontaneously thread itself off. OTOH, I've seen more than a few with stuck bells and bell damage from the REALLY stuck ones.

So a torque specifications seems in order, eh?

Thanks!

Dave

PS: do you suppose the specific oil Aidan uses enable that spectacular mount of his?

...
DIfferent screw-bell topic: have you tried some side-by-side comparisons with your plain versus screw-bell horns? I found the feedback behind the bell to be quite different, and the volume capacity (before the ripping-sheet-metal level) to be notably higher on the screw-bell. That required some careful recalibration of my ear and playing system to avoid getting "the hand" all the time. YMMV.
...

I don't have a side by side.. my current screw flare is a Holton flare that was NOS when they moved out of Wisconsin. It is on a Frankenbass that is mostly Bach. I liked it enough that I have a screw fitting for one of my Bach flares, but that flare is hilariously out of round where the fitting would sit. Like 1/4"+ out.

Back to this question, this flare on the current chassis and the previous Edwards that I had it mounted to for a couple of years does have the ability to get away from me a bit... The feedback is good, though definitely different that the non screw bells, but I like it. The ability for some... over excitement, perhaps on the top end leads me to getting some feedback/hand.

To make sure I am clear, I am happy with the sound and feedback, and have been dancing around, but probably will put a screw fitting on at least one, if not several of my vintage flares. It is just too convenient and I find the effects to be beneficial enough to not be concerned about it (though I hate to make irreversible changes).

To the main topic, I do occasionally lube them. I've used my rotor linkage oil. Mainly because it was what I had in my hand. Be careful with lube... the effect there is that for the same torque on the threads, you get a much increased clamp load in the joint. You are lowering the dynamic friction as the parts move against each other. That is, when it is lubed, for the same effort, you are tightening the flare on more if you have lubricated threads. Could lead to it being difficult to separate if you aren't paying attention.

Cheers,
Andy

[elmsandr]

Andy,

Have you experimented between "just barely snug enough to not rattle" and the fine torque adustment of "gutentite?"

I ask because, like you and Aidan, I DO oil the threads. This avoids both corrosion and galling, but adds the over-torquing risk you mention.

I can hear no difference behind the bell or in recordings between the two torque specifiications above.

If you have the same experience, would you recommend the just barely snug enough?

In all the years I've seen threaded Horn bells I have YET to see even ONE spontaneously thread itself off. OTOH, I've seen more than a few with stuck bells and bell damage from the REALLY stuck ones.

So a torque specifications seems in order, eh?

Thanks!

Dave

PS: do you suppose the specific oil Aidan uses enable that spectacular mount of his?

So, I think I saw it earlier in the thread above... after you do it a couple of times, you get some feedback from your hands on what is needed. As has been noted elsewhere, I am an engineer and somewhat mechanically inclined... I have not found it necessary to think about this too much. It is a thread and it isn't a very complicated one, though it could easily be designed to PREVENT a cross thread, but that is another matter. Maybe I should offer that advice for free to Instrument Innovations to get out of this debate.

Random note on my Holton flare.. the ring was installed a little wonky, so it has an orientation. I can visually see when the rotational position is off after assembly. So it goes pretty much to the same angular position every time I put it on. Add a little sharpie dot on both sides of the ring when you figure out where you want it. Also can help to see when you get a ton of gunk in the threads.

Cheers,
Andy



Cheers,
Andy

[BGuttman]

I wonder why the "bayonet" style connection never caught on. There are many french horns that use it. It's much harder to jam.

[OneTon]

Andy,

Have you experimented between "just barely snug enough to not rattle" and the fine torque adustment of "gutentite?"

I ask because, like you and Aidan, I DO oil the threads. This avoids both corrosion and galling, but adds the over-torquing risk you mention.

I can hear no difference behind the bell or in recordings between the two torque specifiications above.

If you have the same experience, would you recommend the just barely snug enough?

In all the years I've seen threaded Horn bells I have YET to see even ONE spontaneously thread itself off. OTOH, I've seen more than a few with stuck bells and bell damage from the REALLY stuck ones.

So a torque specifications seems in order, eh?

Thanks!

Dave

PS: do you suppose the specific oil Aidan uses enable that spectacular mount of his?

I don't have a side by side.. my current screw flare is a Holton flare that was NOS when they moved out of Wisconsin. It is on a Frankenbass that is mostly Bach. I liked it enough that I have a screw fitting for one of my Bach flares, but that flare is hilariously out of round where the fitting would sit. Like 1/4"+ out.

Back to this question, this flare on the current chassis and the previous Edwards that I had it mounted to for a couple of years does have the ability to get away from me a bit... The feedback is good, though definitely different that the non screw bells, but I like it. The ability for some... over excitement, perhaps on the top end leads me to getting some feedback/hand.

To make sure I am clear, I am happy with the sound and feedback, and have been dancing around, but probably will put a screw fitting on at least one, if not several of my vintage flares. It is just too convenient and I find the effects to be beneficial enough to not be concerned about it (though I hate to make irreversible changes).

To the main topic, I do occasionally lube them. I've used my rotor linkage oil. Mainly because it was what I had in my hand. Be careful with lube... the effect there is that for the same torque on the threads, you get a much increased clamp load in the joint. You are lowering the dynamic friction as the parts move against each other. That is, when it is lubed, for the same effort, you are tightening the flare on more if you have lubricated threads. Could lead to it being difficult to separate if you aren't paying attention.

Cheers,
Andy

Torque specifications would then drive requirements for a unique torque wrench that would not have as much utility as the Ford wrench supplied with Model A cars. Yamaha has a tutorial for screwing on French horn bells in their maintenance guide that should limit over torqued fittings. They even show a picture of the hand cupped in the bell.

Screw threads distribute the loading better than bayonets that would result in more concentrated loads. Bayonet fittings need to be very low cycle usage or have hardened materials to control wear. That doesn’t preclude seeing bayonet fitting usage.

[Burgerbob]

I just use my ultra pure linkage oil. I don't put it on often... I probably should soon.

If I don't oil it, the flare will vibrate unless I torque it a little more than I would like.

[BigBadandBass]

If I don't oil it, the flare will vibrate unless I torque it a little more than I would like.

Interesting, I can leave the flare half unscrewed and get no vibrations or anything. I do have a horn ring and not a trombone ring, I wonder if the threading or tolerances are different. Either way it makes for great fun to give your flare to a horn player and receive a horn flare in return

[BGuttman]

... it makes for great fun to give your flare to a horn player and receive a horn flare in return

It must be a challenge to put your trombone together with a French Horn flare

[BigBadandBass]

It must be a challenge to put your trombone together with a French Horn flare

Well it did fit on with the slide, but the slide and bell were touching, certainly was the most interesting sounding Bb I have ever played

[harrisonreed]

Don't twist it -- just push it onto the stem until you hear a loud "kuh-thunk!!"