plating valves -- Tuba valves

I'm hoping some of you machinist/fabricators might have some insight into my non-motorcycle problem.
I have a hundred year old tuba I play in the local orchestra. I has a wonderful sound but the four valves are loose making it extra hard to play in tune (it's not easy under the best of conditions). They are up to 0.004" and should be about 0.0005 to 0.0015. If I still had access to Pokes Cycle's pin fitter I could have any plater plate the piston valves and I could hone the bores to fit on the Sunnen machine. But I don't have access to those machines anymore.

The local tuba specialist, who does have a pin fitter, refuses to work on it for me. The people who do instrument-valve plating will not do it for individuals, only shops.

So, how thick is chrome typically and would that be the best material; or maybe nickel first? Maybe monel? Perhaps I could plate them only enough to take up some of the slack. How precise is the plating process? I know they hard chrome valve stems but to they grind them afterwards?

Really fascinating stuff, I don't have an answer but am curious to see who and what shows up...good luck, hope you get it "tuned" to where you want it.

Generally, plating doesn't go on smoothly enough to provide the kind of seal you would need. That's especially true of hard chrome. I've done quite a bit of valve work on trumpets, valve 'bones, and tubas. I generally work with nickel plating, but I just ordered the Caswell hard chrome plating kit. That's because I have a horn with nickel valves that the plating company I usually use (Anderson in Elkhart IN) won't plate over nickel.

To do it right, you need to plate, then machine down. This can be done with a hinged wooden valve block--available through Ferree's Tools--that lets you use valve grinding paste to achieve a uniform diameter. Usually, rebuilding a valve block on a tuba requires not only building up the valves, but plating them to an oversize, and then honing the cylinder bore to make them fit. Not an easy process, but it works.

Thomasa said:

I'm hoping some of you machinist/fabricators might have some insight into my non-motorcycle problem.
I have a hundred year old tuba I play in the local orchestra. I has a wonderful sound but the four valves are loose making it extra hard to play in tune (it's not easy under the best of conditions). They are up to 0.004" and should be about 0.0005 to 0.0015. If I still had access to Pokes Cycle's pin fitter I could have any plater plate the piston valves and I could hone the bores to fit on the Sunnen machine. But I don't have access to those machines anymore.

The local tuba specialist, who does have a pin fitter, refuses to work on it for me. The people who do instrument-valve plating will not do it for individuals, only shops.

So, how thick is chrome typically and would that be the best material; or maybe nickel first? Maybe monel? Perhaps I could plate them only enough to take up some of the slack. How precise is the plating process? I know they hard chrome valve stems but to they grind them afterwards?

Click to expand...

I have no idea if it would work but I use the Eastwood Tin/Zinc electroplating kit many things. By varying the time, you can make it thicker or thinner and rubbing with "SOS" pad you can make it very shinny. If it doesn't work you can reverse the polarity and un-plate. Of course, all plating I'm aware of uses acid, at least weak acid, so you would want to be careful. I have never measured how much it builds up.

You might contact this guy:

I realise he works on saxophones but would Jim Schmidt be able to help?

Doctortrombone said:

Generally, plating doesn't go on smoothly enough to provide the kind of seal you would need. That's especially true of hard chrome. I've done quite a bit of valve work on trumpets, valve 'bones, and tubas. I generally work with nickel plating, but I just ordered the Caswell hard chrome plating kit. That's because I have a horn with nickel valves that the plating company I usually use (Anderson in Elkhart IN) won't plate over nickel.

To do it right, you need to plate, then machine down. This can be done with a hinged wooden valve block--available through Ferree's Tools--that lets you use valve grinding paste to achieve a uniform diameter. Usually, rebuilding a valve block on a tuba requires not only building up the valves, but plating them to an oversize, and then honing the cylinder bore to make them fit. Not an easy process, but it works.

Click to expand...

This is probably beyond my capabilities. What really needs to happen is for someone to pull the valve block, plate the valves, grind them to size and fit the bores to the pistons. I have no idea what Martin used for valve surfaces in 1918.

Perhaps there is someone in the Pacific Northwest who could do the work in a timely manner; like a couple of months over the summer.

Oberloh in Seattle won't work on it and said I should just buy a new Tuba but I believe old J.W. Yorks and Martins are worth fixing. So does he but he had some falling out with my mentor, ex of Seattle Symphony, and associates me with him.

I've read that Chicago Symphony has several Yorks they won't sell and a Martin Monster. Besides, as I'm sure you know, new, good, 4-valve tubas are beyond $10K. My horn is a 17 inch 4-valve Eb, fits in the trunk of my car, and I can play it down to F# below the Bass staff and that's all I'm ever called upon to play, I can get it to the Eb below that with time. Plus, I can play it to middle C, which I am called upon to play in the absence of a Bass Trombone. For our next concert I'm called to do both F# and Middle C. With tighter valves "Appalachian Spring" would be a lot easier. I have to play that Thursday. So if money were no object what tuba would I buy?

The rest of the time I play assorted trumpets, from an old J.W. York cornet to a Buescher Big B to an LA Benge, which is my favorite. In my younger days I played 1st trumpet on it. Only the York needs valve work, and a new, longer tuning slide. The old A slide is gone. I only play it for novelty blues stuff with a toilet plunger for a mute, which the crowd loves. So intonation isn't all that critical. But with the tuba which can easily fill the hall with sound, intonation matters a lot.

marshg246 said:

I have no idea if it would work but I use the Eastwood Tin/Zinc electroplating kit many things. By varying the time, you can make it thicker or thinner and rubbing with "SOS" pad you can make it very shinny. If it doesn't work you can reverse the polarity and un-plate. Of course, all plating I'm aware of uses acid, at least weak acid, so you would want to be careful. I have never measured how much it builds up.

You might contact this guy:

Click to expand...

I might try that Eastwood plating method on the outside where the silver plate has been worn through. Someone in the past hunderd years plated the front of the bell where it sticks up above the orchestra. Where my arms go round it is all worn through to brass.

I used the Caswell home plating system on my ES2 . Bright Nickel over flash copper. Great results and not difficult. Just like painting, most of the work is in the prep . I haven’t a clue as to the thickness but as others have noted you can built it up .

...but can you tune the old ES2 down to F sharp?

The exhaust note on an ES2 at F sharp 1 (4 leger lines below the Bass clef staff) would be 5239 RPM given that is fires every other time. A Commando would be half that. So a commando sounds an octave higher than a single. Wind a commando up to typical top end and you're into guitar range, that bottom E string anyway.

FWIW I've tuned bicycle spokes using the tuning app on my phone. I often use G 4 at 390 hz on the drive side spokes of a 10 speed Campy hub. Works as well or better than a spoke tension gauge. Haven't tried it on a motorcycle wheel.

Thomasa said:

The exhaust note on an ES2 at F sharp 1 (4 leger lines below the Bass clef staff) would be 5239 RPM given that is fires every other time. A Commando would be half that. So a commando sounds an octave higher than a single. Wind a commando up to typical top end and you're into guitar range, that bottom E string anyway.

FWIW I've tuned bicycle spokes using the tuning app on my phone. I often use G 4 at 390 hz on the drive side spokes of a 10 speed Campy hub. Works as well or better than a spoke tension gauge. Haven't tried it on a motorcycle wheel.

Click to expand...

At 7000 RPM, the note of my 850 is the D above middle C onthe piano. If it reaches E , I have gone too far. Sometimes it is impossible to look at the tacho.

Richard Tool said:

I used the Caswell home plating system on my ES2 . Bright Nickel over flash copper. Great results and not difficult. Just like painting, most of the work is in the prep . I haven’t a clue as to the thickness but as others have noted you can built it up .

Click to expand...

If you are seeking a wear surface chromium is probably the way to go. A couple of thou of an inch probably won't need grinding. However getting the chrome to stickmight be a problem. Chrome plating is different from most other types in the way it is done. With most other metals, if you have a clean steel or copper surface, you make your job the cathode, put it in the solution and apply current - no probs ! With chrome, when you do that, it will not plate. You need a reversing switch. Reverse etch at 100 amp per square foot, and then reverse the polarity. When you reverse etch, an anode slime forms. When the switch is reversed an over-potential condition occurs - the chromium strikes through the slime. From then on it is the same as any other plating. If the current is interrupted, the plating might double-coat. Nickel is the worst type of plating for double coating. You end-up with the second coat not adhering to the first.
One of the fun things I did in my life, was chromium plate the bore of a 5 inch gun barrel. We took it to South Australia and fired a few rounds into Spencer's Gulf.
I cannot imagine what the bits you are playing with look like. Sometimes you might be better-off remanufacturing, if they can be taken apart.

acotrel said:

If you are seeking a wear surface chromium is probably the way to go. A couple of thou of an inch probably won't need grinding. However getting the chrome to stickmight be a problem. Chrome plating is different from most other types in the way it is done. With most other metals, if you have a clean steel or copper surface, you make your job the cathode, put it in the solution and apply current - no probs ! With chrome, when you do that, it will not plate. You need a reversing switch. Reverse etch at 100 amp per square foot, and then reverse the polarity. When you reverse etch, an anode slime forms. When the switch is reversed an over-potential condition occurs - the chromium strikes through the slime. From then on it is the same as any other plating. If the current is interrupted, the plating might double-coat. Nickel is the worst type of plating for double coating. You end-up with the second coat not adhering to the first.
One of the fun things I did in my life, was chromium plate the bore of a 5 inch gun barrel. We took it to South Australia and fired a few rounds into Spencer's Gulf.
I cannot imagine what the bits you are playing with look like. Sometimes you might be better-off remanufacturing, if they can be taken apart.

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Remanufacturing is out of the question. Way too complex. One might be able to buy a new valve block consisting of three or four valves but then the tubing needs to be reformed to fit the new valve block. Pros could do that but that's way beyond my skills.
The piston part of the valve is a hollow cylinder about four inches long with two sets of transverse holes bored at odd angles to duct the sound waves to the corresponding tube on the other side of the valve. The holes are tubes in themselves with curves to get them to the other side at a different level in the cylinder. Difficult to explain. Look up https://en.wikipedia.org/wiki/Brass_instrument_valve for a schematic drawing and some photos.

Nickel plating is the easiest to do at home, but any interruption to the current while the metal is being deposited can cause 'double coating'. I cannot remember what solution is used to strip nickel. You could probably just reverse the current if you needed to remove it because of a problem. Getting the parts clean enough might be a problem - it is normal to degrease then pickle in acid. If the material is copper-based with tin, dilute nitric acid might be good.

Getting the fit right might need a bit of care. If you know how much metal you want to add, and the plating rate, it is not difficult - but you might need to make some dummy parts to find out how fast the nickle plates on, before you plate your valuable bits.

acotrel said:

Getting the fit right might need a bit of care. If you know how much metal you want to add, and the plating rate, it is not difficult - but you might need to make some dummy parts to find out how fast the nickle plates on, before you plate your valuable bits.

Click to expand...

I have been involved in plating hard chromium to thickness. We used test plates to find out how many thou per hour plated on, and carefully controlled the composition of the bath. It can be done very precisely. Alternatively, you could add too much nickel then polish it down to size. If you don't get it right the part might stick in the bore when you try it for size.