TromboneChat

A friend sent me this article about the Martin "Committee" trombones from (apparently) 1939.
You may be interested:
https://docs.google.com/file/d/0B5-_7UC ... VSOTg/edit

Hold on a minute...

the inner slide tubes are made of nickel steel?

Makes sense... I have a committee deluxe that has some plating wear on the inners, and it looks like there are flecks of rust on them.

JohnL wrote: ↑Thu Jul 25, 2019 8:50 am Hold on a minute...

the inner slide tubes are made of nickel steel?

I have that model and the slide is perfect. My horn is in mint condition.

/Tom

paulyg wrote: ↑Thu Jul 25, 2019 10:34 am Makes sense... I have a committee deluxe that has some plating wear on the inners, and it looks like there are flecks of rust on them.

Is it magnetic? Not a conclusive test (LOTS of nickel will make steel non-magnetic), but a start.

JohnL wrote: ↑Thu Jul 25, 2019 11:29 am

paulyg wrote: ↑Thu Jul 25, 2019 10:34 am Makes sense... I have a committee deluxe that has some plating wear on the inners, and it looks like there are flecks of rust on them.

Is it magnetic? Not a conclusive test (LOTS of nickel will make steel non-magnetic), but a start.

If magnetic, then it's steel. If not, still could be steel. Although I would have thought any steel you could easily draw a tube with would be magnetic.

So, on to the second test. Hit it with a grinding wheel and check the color of the sparks. Steel should give you those characteristic bluish white fireworks clusters.

I used to own a Committee. The inner slide did not appear to be steel. It was too light. Steel the thickness of the metal would have been much heavier.

I would not be surprised if the inner was nickel silver (which is a copper alloy and contains no silver).

Sadly, I no longer own the instrument and can't test it for you.

Most inner slide tubes on pro horns are nickel silver. Possibly a typo?

BGuttman wrote: ↑Thu Jul 25, 2019 2:29 pm I used to own a Committee. The inner slide did not appear to be steel. It was too light. Steel the thickness of the metal would have been much heavier.

Are you sure?

This chart:
https://www.machinemfg.com/density-tabl ... um-alloys/

lists brass at density of 8.8 and steel at 7.8. If the steel is the same thickness, it should be lighter?

Many thanks to Posaunus for the great historic information.
It is possible that Martin inners could have been steel at one time, as steel /nickel alloys were available.
https://www.brighthubengineering.com/ma ... eel-alloy/

Nickel-iron alloys have been available for a long time as "stainless steel". Commonly used in surgical instruments and where corrosion is a problem.

The issue with using any iron alloy is the greater difficulty in drawing tubes (although most heat exchangers use stainless steel tubes) and the inner being quite rigid possibly creating a problem with the more flexible brass outer slide. It's also much harder and thus may make a rather strident tone.

Just noticed: I'm playing my Committee in my avatar

BGuttman wrote: ↑Thu Jul 25, 2019 2:29 pm I used to own a Committee. The inner slide did not appear to be steel. It was too light. Steel the thickness of the metal would have been much heavier.

Steel – even with lots of nickel – is not denser than brass or "nickel silver."
Therefore a steel slide should not be any heavier than other slides with similar wall thickness.