Some of the Smith-Corona 6 series machines (electrics) came with copper shipping restraints that were meant to be removed by the dealer prior to sale. Sometimes they can be found inside cases and in other instances, inside the typewriter itself.

via: https://old.reddit.com/r/typewriters/comments/1ew971o/need_help_finding_where_this_came_from_more/

See also:<br /> https://imgur.com/a/xbo6SoY<br />

https://imgur.com/a/PMPCXN5<br />

Smith-Corona Series 5 and 6 typewriters had a small piece of rubber around a portion of the escapement which can wear out or become damaged. This in turn causes the escapement to not work properly and cause the dogs to get jammed resulting in large movements of the carriage while typing or spacing.

Joe Van Cleave calls it the "return silencer" and replaced his by tracing out the damaged piece on a sheet of 1/32" rubber and cutting it out as a replacement.

Duane at Phoenix typewriter describes replacing it with rubber tubing (possibly something like heat shrink?) instead. See: https://hypothes.is/a/tG4BWk77Ee-jczsjoM8SzA

SCM Electric Typewriters by [[Joe Van Cleave]]

Tips for cleaning the Smith-Corona 6 series electric typewriters and details about how they work.

S-C also made this series of typewriter for both Sears and Singer under their branding. (including the Singer Electric in this video.)

The belts on the electric motor and cams was originally a rubber 'V' belt which is no longer manufactured. Using 1/8" round cross-section o-rings of appropriate sizes (for water cannister applications) is the recommended replacement, however one may need to slightly move the drive motor down a bit so that the belt doesn't hit the frame of the typewriter and thereby destroying it over time.

Cleaning and lubricating the drive motors and moving pieces before using may help before trying out a typewriter which has been sitting for long periods of time.

Some later models had an electric return, which can tend to be violent. Electro 220 and Coronet Automatic 12 have an additional clutch and draw band (and lack of return lever on the carriage) for their electric returns.