Donor IBM Selectric 1 purchased; rear cover on its way here

IBM 1053 TYPEWRITER PRINT SHAFT TOO CORRODED TO REPAIR

The corrosion of the print shaft, which the carrier slides along while typing, tabbing, spacing or returning, is too heavy to sand off and still have reliable operation. I need a new one, which I will take from another typewriter of the same era and size. 

The 1053 is a version of the IBM Selectric 1 (original), which came in several widths. The one used with the 1053 has a platen whose rubber is 13" wide, providing support for roughly 11 1/2 inch wide lines with the end stops set as wide as possible. I located some used Selectric 1 typewriters, picked those with the same platen width and with a visually uncorroded print shaft after inspecting pictures. 

One seller listed with a Make an Offer button but had the system set up to autoreject any offer other than the Buy It Now price. They didn't pretend to look over the offer and make a decision, they had the system set up to bounce any offer. Even though that machine would have been the same total price including shipping as other listings, I refuse to reward those who game the system and don't intend to seriously look at any offer below their list. I therefore bought a different unit and expect it in a week or so.

The process from that point is to disassemble the shaft, which normally involves disconnecting the tilt and rotate tapes as well as the cord that powers all carrier left-right movement. On this machine, one of the tapes was already broken anyway and I would have had to do part of this work without touching the print shaft. 

This shaft is cylindrical in cross section and the carrier has plastic bushings that the shaft fits through, and which allow the carrier to move along the shaft. A lengthwise slot in the print shaft engages with the mechanism on the carrier that lifts the typeball and ribbon up and swings the ball forward to print. Thus, the shaft rotates once for each character printed, powering the ball and ribbon mechanisms. Meanwhile. the movement mechanisms - space, backspace, tab and carrier return - slide the carrier along the print shaft in the desired direction and for the intended distance. 

Because the carrier is able to move from one side of the typewriter to the other, it is hooked on both sides to a cord that wraps around a pulley powered by a mainspring and wound up by the operational shaft during a carrier return. The forward operations are powered by the unwinding of the mainspring. The cord attaches to the sides of the carrier in a very straightforward manner, then runs through pulleys on the sides of the machine and then around the mainspring pulley. 

The character to be printed is powered by rotation and tilting of the ball mechanism, using one metal tape to select one of four tilt increments of the ball and another tape to select one of five rotation steps in either the clockwise or counterclockwise direction. Thus we can select any of 11 rotations and four tilts to choose which of the 44 characters on a hemisphere of the typeball to face the platen when we print ne character. 

The ball can be rotated 180 degrees to the other hemisphere by an upshift or a downshift operation, which moves one of the metal tapes to one of two ranges. Within each range the tape offers the 11 rotation positions. A shift operation takes one machine cycle, separate from the cycle needed to print a character. 

The two metal tapes attach to the carrier on each side and then run around a set of pulleys on the side of the typewriter, so that the tape moves the same distance as the carrier during motion, then one of the end pulleys is levered to impart the extra movement of the tilt, rotate and shift action. The rotate tape has round end that is fitted into a rotary cam under the carrier and winds around the cam before being threaded though the pulleys on both sides of the machine and hooked to a fixed position on the carrier. The tilt tape has an easier connection to a more accessible rotary part under the carrier. 

REAR COVER PART WAS FABRICATED AND IS IN TRANSIT TO MY SHOP

The cover was shipped yesterday and is due to arrive by the end of day on Monday 9/25. There is some painting and assembly of mounting hardware before I can install it on the rear of the 1130 display pedestal.