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Strange neck tenon wear marks on a new alto

Selvasis

New Member
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8
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England, UK
Heya guys,

Long time lurker here. Finally decided to create an account, since this community has been very helpful for me, coming in from Google searches and the sort, especially about technical things relating to our favorite horn.

I recently purchased a brand new Taiwanese alto, which is very similar in construction to a Cannonball, and the sax feels and sounds great (but could be better? Could it?)

I've always been a stickler for good neck fit, and this horn appears to have so. No wobbling, and only a quarter turn or less before the neck is secure. I do not overtighten, as I'm aware of the bubble effect that can happen underneath. The sax has no appreciable leaks when putting a leak light through, and a pop test (see sax technician Matt Stohrer's videos on YouTube) make for a pretty darn good seal.

However, the horn doesn't "sing" with extreme clarity, and it responds like an old Keilwerth I had that had a tight fitting neck, but a surefiredly leaking one (out of round). There's an ever slight stuffiness to the instrument throughout the whole range, but underneath if I push it, I can hear the depth of tone I'm looking for.

Taking the neck out, I'm seeing these weird high spots, especially after rotating the neck out gently. 3 shiny lines, where the tenon meets the receiver, Inside the receiver, it's just as strange a story.

Is this indicative of a leaking neck? Considering however that there is a clear and defined contact at the bottom 3/8th of the neck tenon, I'm assuming that's all the real sealing I'd need, but I just want to reassure myself that it's not a leaking neck.

I'm a professional touring musician in the Philippines, and I'm sad to say that the technicians here, including my preferred one, lack the tools and technical knowhow to diagnose or fix something like this. I'm just looking for input, so I can weigh my options. I'm pretty OC about the condition of my horn and leaks, so this will keep bothering me till I know for sure.

I've copied below the link to my Google Drive folder with pictures of the neck tenon and receiver. I'm not really sure if this is the right way to show my issue, or if there's a better way, please let me know.

Sax Leak - Google Drive

Cheers guys! Pictures attached!
 

jbtsax

Well-Known Member
Café Supporter
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9,155
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Beautiful Springville, Utah USA
Those marks inside the receiver and on the tenon itself are called "scoring". Basically it is caused by some foreign material getting in between the tenon and receiver and making "scratches" as the neck is turned and put in and taken out. Your description of this as a "brand new" Taiwanese sax is a bit troublesome. Both the "scoring" and the wear pattern tell the story that this neck was poorly fit at the factory. Sometimes small bits of brass called burrs can break off where the slot has been cut and cause some of this type of marking.

The good news is that this can be repaired by "lapping" the neck with a lapping compound, cleaning the tenon and receiver, expanding the neck tenon, and repeating the process till the parts have an even finish inside an out.
 

Selvasis

New Member
Messages
8
Locality
England, UK
Those marks inside the receiver and on the tenon itself are called "scoring". Basically it is caused by some foreign material getting in between the tenon and receiver and making "scratches" as the neck is turned and put in and taken out. Your description of this as a "brand new" Taiwanese sax is a bit troublesome. Both the "scoring" and the wear pattern tell the story that this neck was poorly fit at the factory. Sometimes small bits of brass called burrs can break off where the slot has been cut and cause some of this type of marking.

The good news is that this can be repaired by "lapping" the neck with a lapping compound, cleaning the tenon and receiver, expanding the neck tenon, and repeating the process till the parts have an even finish inside an out.

Thank you, jbtsax!

So, my neck is definitely leaky. That's pretty sad stuff, but I guess not all that uncommon. This was a brand new horn after being impressed with the display horn that I tried of the same model.

Is there any chance that these high spots will subside after some usage? Or if I were to use, let's say, toothpaste, for a couple rounds of light lapping and test-fitting?

I don't have access to a competent tech for this, and pending Ken Beason supposedly visiting the country in late June (and also questionable if he's bringing neck tenon tools), I might either have to deal with it myself, or another neck which I'm worried might have the same problem.
 

kevgermany

ex Landrover Nut
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Just north of Munich
Agree with jbt on the scoring and lapping being the answer.. Also looks to me as if the socket isn't round, has high spots. The wear marks on the tenon are in bands, may be caused by rotation against the high spots as you push the tenon in.

Maybe get hold of the tech who's going to visit, get him to bring the necessary tools.
 

MMM

Senior Member
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1,139
Locality
SW of London Town
If you want to satisfy yourself it is definitely leaking, here's a cheap and quick way to test the seal:
wipe clean neck tenon and receiver, put lots of cork grease on the tenon and put the neck on the body, play it: is there any difference to the response? If there is then there is a leak.

NB.: after the test, make sure you wipe carefully all the cork grease off the neck tenon and receiver (including the neck screw slot).
 

Targa

Among the pigeons
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Put some soapy water in the joint and play 'I'm forever blowing bubbles' and see if there are any.
 

Keep Blowing

Senior Member
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1,708
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Bottesford England
I'm not a tech but could you you some PTFE tape, (plumbers tape) to test whether you have a leak. Push the neck in until it is nearly all the way in. Wrap some tape round the neck and gently push it in, this should create a seal. Or push it in and then wrap the tape tightly over the seal
 

MMM

Senior Member
Messages
1,139
Locality
SW of London Town
I'm not a tech but could you you some PTFE tape, (plumbers tape) to test whether you have a leak. Push the neck in until it is nearly all the way in. Wrap some tape round the neck and gently push it in, this should create a seal. Or push it in and then wrap the tape tightly over the seal
If the neck is a good fit, I doubt you would be able to put PTFE tape around it and insert it without having to apply some force. The beauty of using grease is that it spreads closing any minute gaps and it allows for easy insertion/removal, without risk of bending the neck.
I have used PTFE tape when a neck tenon is too loose (usually when testing/experimenting with non original necks), but this implies quite a gap between tenon and receiver.
 

Keep Blowing

Senior Member
Messages
1,708
Locality
Bottesford England
If the neck is a good fit, I doubt you would be able to put PTFE tape around it and insert it without having to apply some force. The beauty of using grease is that it spreads closing any minute gaps and it allows for easy insertion/removal, without risk of bending the neck.
I have used PTFE tape when a neck tenon is too loose (usually when testing/experimenting with non original necks), but this implies quite a gap between tenon and receiver.
I used to be a pipe fitter, so these things spring to mind, that's what I would do but the grease does sound a better option
 

kevgermany

ex Landrover Nut
Café Supporter
Messages
21,378
Locality
Just north of Munich
I used to be a pipe fitter, so these things spring to mind, that's what I would do but the grease does sound a better option
I tried it with a neck that was wobbling. Couldn't get the tape past the opening cos it was too tight.
 

kevgermany

ex Landrover Nut
Café Supporter
Messages
21,378
Locality
Just north of Munich
NB.: after the test, make sure you wipe carefully all the cork grease off the neck tenon and receiver (including the neck screw slot).
Agree, really important, otherwise the grease traps grit that scores the tenon/socket. Not to mention the mess in your case.
 

Janosax

Member
Messages
336
Locality
France
The way I test my sax for general leaks is that one: I put some food film all over the bell hole, mount the neck, close all keys to low Bb and then suck air from the neck. Keys should stay closed by themselves if there is no leak. You can also push air and ask for someone to listen near the neck if there is any air leak.
 

jbtsax

Well-Known Member
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Messages
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Locality
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The way I test my sax for general leaks is that one: I put some food film all over the bell hole, mount the neck, close all keys to low Bb and then suck air from the neck. Keys should stay closed by themselves if there is no leak. You can also push air and ask for someone to listen near the neck if there is any air leak.

Does that really work on a saxophone? How long do the keys stay closed? I have done that on flute, but flute pads are completely airtight. Saxophone pads typically are not. The chart below is from a test I did on pad "porosity" using a Magnehelic which measures air pressure loss. Only the gold, neoprene and Pisoni Pro J pads were 100% airtight at the higher pressure tested.

1526650995720.jpeg
 

Janosax

Member
Messages
336
Locality
France
Very interesting thanks for that. I must say that pads stay closed on my sax for perhaps 1 second if I block air from escaping with my tongue on the neck after air succion. There is also certainly some air dilatation just after stopping succion and strong springs forces. If I don’t stop, pads stay closed as long as it’s possible to maintain aspiration. With a big leak, I think it should not be possible at all. It’s a bit like the mouthpiece reed pop test.
 
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