Replacing Thayer Valve on Bach 42T with Infinity Valve - Gooseneck

[tbonesullivan]

I haven't been playing my trusty 42T as much recently, partly because the valve on it is really not working as well as it used to. It's an early production 42T, with the gray core, and the coating is a bit eroded in places. I have had it worked on a bunch, but slowly it is getting worse. I use Hetman oils, which prevent any oxidation, but with there not really being a supplier for parts on these, I figured it might be time to have it replaced with an Infinity valve, as I assume that the old wrap can be used for the new valve.

One thing that I was wondering about though was the "gooseneck" used on it, which is an "S" shaped tube, I believe that were supplied with the valve. The current Bach 42AF trombones use a different tube, so of course I wonder whether that tube will work or sound "better". I have a picture below:



Of course I'm also wondering overall how different the sound is with the infinity valve. I do like how my 42T sounds now, and I can definitely live with having to oiling my valve every day. It's just time consuming.

[Bonearzt]

The new Infinity valves play quite a bit better than the older Thayers as the tolerances are a LOT tighter.
The original axials tend to be a bit "loose", but the cone bearing in the Infinity really helps the valve seal!

They are a bit finicky to install though, and not a straight "plug & play" as the port configuration is different and requires a good bit of replumbing to fit to the valve. But an older horn like yours would benefit from a good rebuild to relieve the stresses of age!

[Crazy4Tbone86]

A couple of years ago, Mike Olsen reconfigured his offset tubing (piece that goes from the axial valve into the F-tubing). He told me the amount of the adjustment, but I can't remember it now (maybe 7 or 8 degrees?). But, anyway....it makes for constructing axial sections with no tension much easier now.

[brassmedic]

That S bend neckpipe on the original 42T came with the Thayer kit and wasn't designed to fit Bach trombones, but Bach used it anyway. The receiver on a 42 is angled outward, but the Thayer neckpipe goes in a straight (albeit offset) line from the tuning slide, and the offset is a little too much, so a lot of the 42Ts look strange if you really examine how the neckpipe lines up. So no, I don't think they are intrinsically better than the newer neckpipes.

Here's an example. The valve is straight in line with the neckpipe, but the receiver is angled, so they just put it on at an angle, leaving a gap on one side where the receiver connects to the valve.

Bach-42-Thayer-26.06.2021-5-scaled.jpg

[hornbuilder]

That alignment issue is because they were using pre-assembled kits. If you start out with a box 'O parts, you can assemble the casing to the handslide receiver, and go from there.

[tbonesullivan]

Here's an example. The valve is straight in line with the neckpipe, but the receiver is angled, so they just put it on at an angle, leaving a gap on one side where the receiver connects to the valve.

I've had the valve worked on twice. It is valve serial 0064, and was probably one of the first sent to Bach, and is marked Orla Ed Thayer on the casing. It was assembled with end play, as Bach didn't know how to fit the valves. I bought in in college and did not know what I know how, such as how to check valves for slop, end play, hop, etc.

I had it serviced by Osmun and they removed the end play and such, and it played a lot better.

Next time It had problems I sent it to Benn Hansson, and he corrected the issue with the slide receiver:



He also slightly expanded one of the legs of the main tuning slide, as fixing the valve and such also caused the main tuning slide to actually be PARALLEL, and even with super thick grease it was really loose and would slide inward.

[Crazy4Tbone86]

The photo that Brad attached shows an assortment of problems with Thayer kits. Brad noted the sharp angle in which the slide receiver goes into the bottom of the cone casing. If you look at the top of the gooseneck, you will notice that connection has a slightly skewed angle as well. Yet the gooseneck appears to be rather true going into the top of the casing (actually, it is tricky to tell from that photo). If you look at the F-attachment tubing over by the bell, you will see that the entire F-tubing section is not true to the bell stem as well. The last angle is not as important because the horn will probably play very well if the F tubing is all true and tension-free within itself. However, I think an instrument has more cosmetic appeal if all the tubings (main tuning slide and F tuning slide) are true with each other.

When working with the kits, I always triy to bend the angles on the gooseneck to create a bell section that fits together more naturally. If I cannot get the angles perfect on the gooseneck, I attempt to absorb the angle difference equally with all three solder joints (bell-receiver to casing, casing to gooseneck and gooseneck to small side of tuning slide).

The angles in the F-tubing are a whole new chapter of issues. For many years, many of the kits were supplied with an offset that placed the ends on a parallel plane. The result is usually what you see in the photo that Brad attached......the F-tubing is not parallel with the rest of the bell section OR the tubing is parallel and ridden with stress. That's why I mentioned the new offset supplied by Mike Olsen at Instrument Innovations....he adjusted the angle so that the assembly of the F tubing is much easier to set up.

In the end, you are at the mercy of who assembles your horn. Having all the "right parts" does not guarantee that it will be assembled correctly or play very well. Experience and know-how are a HUGE factor in the assembly of Thayer bell section.

[tbonesullivan]

The angles in the F-tubing are a whole new chapter of issues. For many years, many of the kits were supplied with an offset that placed the ends on a parallel plane. The result is usually what you see in the photo that Brad attached......the F-tubing is not parallel with the rest of the bell section OR the tubing is parallel and ridden with stress. That's why I mentioned the new offset supplied by Mike Olsen at Instrument Innovations....he adjusted the angle so that the assembly of the F tubing is much easier to set up.

In the end, you are at the mercy of who assembles your horn. Having all the "right parts" does not guarantee that it will be assembled correctly or play very well. Experience and know-how are a HUGE factor in the assembly of Thayer bell section.

Looking at my horn I do realize that the bell section is definitely going to require quite a bit of disassembly, even to convert it to something pretty much the same as a Bach 42 AF. I had considered maybe just selling it, but it does have sentimental value, and also it sounds really good, at least I think it does. I assume it would sound even better once re-assembled with the infinity valve, but I do see now that it is not nearly as simple as just swapping out the valve and goose neck. Now part of me is thinking "why not just replace the valve with something else.

Definitely a lot to think about.

[Matt K]

Having done both, that's certainly the direction I'd take it. Tubing isn't going to be that expensive. Aside from the labor, the rotor followed by the linkage are going to be your most expensive line items. You can possibly re-use some tubing regardless what valve you choose if you really want to but it isn't going to save you a whole heck of a lot. That said, Thayers do tend to work really well on Bachs so maybe get a tech who has done an infinity valve conversion and send it on over to them. Couple forum members have done that work several times... see pictures of their handiwork somewhat regularly. They can probably get you a pretty close estimate for total cost.

[tbonesullivan]

Having done both, that's certainly the direction I'd take it. Tubing isn't going to be that expensive. Aside from the labor, the rotor followed by the linkage are going to be your most expensive line items. You can possibly re-use some tubing regardless what valve you choose if you really want to but it isn't going to save you a whole heck of a lot. That said, Thayers do tend to work really well on Bachs so maybe get a tech who has done an infinity valve conversion and send it on over to them. Couple forum members have done that work several times... see pictures of their handiwork somewhat regularly. They can probably get you a pretty close estimate for total cost.

I actually do like the feel of the linkage on it, and I think it can be reused. I'd rather deal with the plastic hobby linkage, as I also had to buy a whole bunch when I got some replacements. They are so quiet.

[LIBrassCo]

Personally I'd probably go with the Bosc thayer over the infinity valve. Damn near the same price, and much better product. Not a particularly hard job, I change the valve, lever pivot, and linkage. Linkage gets changed regardless of whether the existing will work or not. Mine will be better, and I like to deliever the best product possible.

[tbonesullivan]

Right now I'm on the fence about just replacing the valve with something else, or replacing the horn entirely with something like a 42BOF, aka what a Bach 42 should be. The ALU core is actually in much better shape than I thought, and there is no "need" to replace it now. However after dealing with the issues, and also the amount of oil that axial flows need, it may just be time to go all rotor, or improved rotor.

See, I can get it to work good for days, but I think even the infinity valve needs a bunch of oil, which means it gets down the tuning slides, so I have to re-grease those all the time, and the grease gets in the valve.. .etc etc. I've just had so much better luck with rotary valve solutions.

[Burgerbob]

.

See, I can get it to work good for days, but I think even the infinity valve needs a bunch of oil, which means it gets down the tuning slides, so I have to re-grease those all the time, and the grease gets in the valve.. .etc etc. I've just had so much better luck with rotary valve solutions.

They need oil, but not a ton. It helps if you use a matched tuning slide grease as well. I never have a problem with any of mine in that regard.

[tbonesullivan]

They need oil, but not a ton. It helps if you use a matched tuning slide grease as well. I never have a problem with any of mine in that regard.

That's good at least. I'll most likely have the opportunity to A / B the 42AF and 42BOF along with my 42T, so I can decide which works best for me. I have found that many of the AF valves aside from my 42T use a pretty heavy linkage. I like the feel of the rotary valves much more.

[Burgerbob]

Stock Bach AF setups are also usually pretty awful. They get them right sometimes, not often.

[tbonesullivan]

Stock Bach AF setups are also usually pretty awful. They get them right sometimes, not often.

Yeah... true. I figured an Open Flow valve is easier to screw up the installation on, and easier to fix.

gotta remember to check the slide outers for warps.

[tbonesullivan]

Just an update. Picked up a "Demo" 42BOF from Dillon Music last week, and I LOVE the valve on it. The throw is great, the feel is great. Pretty sure that I will not go back to axials again, though that does complicate what to do with the 42T. It's been through a lot with me, so I'd love to keep playing it, but changing out the valve to a rotary one would involve getting an entirely new valve section made, which is not exactly cheap. Gonna put it in mothball for a while until I make up my mind.