LM-7 "Military" Model
Bore: .485"-.500" (12.3 mm-12.7 mm)
Bell: 7" (177.8 mm)
At first glance, the Military appears to be simply a Self
Balancing with the addition of a "dazzling hammered finish" (to quote
the Olds description), but
closer examination reveals a second, possibly more significant,
difference - one-piece outer slide tubes, with an area of increased
wall thickness in place of the soldered-on oversleeves used on other
Olds trombones of the time. Olds had pioneered one-piece inner
(elimiating the need for soldered-on stockings) several years
earlier, and the Military was their first model to incorporate outer
tubes made using the same technique (the slight step in the outside
diameter can be seen in two of the images below). Also of note is just
how "narrow" this horn is; compared to the Radio model in my collection,
the outer slide tubes are roughly ½" closer together and the outer
tubes of the tuning slide legs are over ¼" closer together.
interesting feature of the hammered finish is that, while it does not
show through to the inside of the bell in the flare area, it does
show through on the inside of the neckpipe and bell tail (and likely
the tuning slide crook as well, though I don't have the capability to
verify that). It's interesting to speculate on what, if any, impact the
dimpled finish has on the instrument's acoustics.
When it was first introduced, the Military model was the most expensive
trombone in the Olds line; in Chicago Musical Instrument Company's
General Catalog Number 35, it is priced at $135 - compared to $120 for
the Standard, Self Balancing, and Radio models. The Military could be
the hammered finish for only $120, and the other models could be had
with the hammered finish an extra charge of $25. This
particular horn dates from the early 1930's and carries two serial
numbers; 73xx on the bell section (also marked LM) and 7487 on the
A point of clarification: as far as I've been able to determine, the
Military model was not
specifically designed or produced for use in military bands. "Military"
was simply a model name - used to imply "the exactness and precision of
a Military Band" (to quote the description in CMI Catalog #35).
Instruments made under contract for the US military would normally have
been marked "US". I have seen "US"-marked Olds instruments, but none of
the were Military models.
Bell Rim Engraving
Outer Slide Detail
Bell Braces and
Slide Braces and
Closeup of "Step"
in Outer Slide