3D printing mounting hardware for door, continued tweaking typewriter (1053 Console)

NEW HARDWARE FOR MOUNTING REAR COVER ON DISPLAY PEDESTAL

The main issue I had with the first attempt was that the exterior parts of the mounting hardware were large and clunky. Rather than using four T handles to secure the cover, I designed a new part for the lower edge that will sit on the bottom lip edge of the pedestal display cabinet. This new design means we only have a single visible screw head on the outside of the cover behind each of the two lower edge parts. . 

For the two side mount mechanisms that will latch the cover in place or release it, I kept the T handle for the outside but developed a set of rotating parts, spring loaded, so that the user pushes in and turns the handle 90 degrees to release the latch. Other than the 3D printed parts I will use a spring, two T handles two screws and four nuts with epoxy securing the nuts to my interior parts. 

The arm part on the left faces down onto the holder part on the right, so that the bulge in the arm will nestle into the gaps on the holder in one of two rotary positions. The holder is attached to the rear of the cover with epoxy and sits so that the edge that is closest to the hole is next to the lip edge of the display pedestal enclosure. 

Thus the arm, when the bulge is fitted into the gap opposite the lip edge, will extend over the rear of the lip edge and keep the cover from opening. Rotating so the arm bulge fits in the other gap, the arm will be rotated parallel to the lip edge and thus allowing the cover to pivot out. 

A spring sits between the T handle head of a bolt and the cover, so that it tends to pull the bolt outwards. The arm is epoxied to the nut on the end of the bolt. Thus the spring keeps the arm pulled into the holder so the bulge and gap blocks rotation. Pushing forward on the T handle against the spring allows the arm to move away from the holder and be rotated. 

TRIED OUT MY NEW 3D PRINTER TO BUILD THE PARTS

I had picked up a 3D printer from a fellow computer restorer - so it is used because he owned it before but it is new to me. I brought my mounting hardware files to the shop, adjusted the printer and gave it a try printing these in ABS plastic. 

I am still having difficulty getting the printer to start the first layer reliably, but I work on it every day so eventually . . . 

TYPEWRITER MECHANISMS CLEANED AND ADJUSTED

There are so very many tiny parts, pivots, levers, springs and the like on a Selectric typewriter, all of which have the potential to be gummed up from stale lubricants. A good working estimate is 3,000 parts. Now that I have addressed all the larger and more obvious components, it was time to focus down on the tiny details that remain stuck.

The ribbon advance mechanism is a case in point, As the typeball is thrown forward to type a character, it should slide a plate forward which has pawls that would turn one of the two ribbon axles. The pawls as well as the plate were stuck with sludge, but with some reoiling and careful manipulation they are ready to go. 

Character selection to rotate the typeball involves four levers that are pulled down in specific patterns to cause the rotate tape to be pulled out or released inwards a given amount, ultimately turning the ball within a 180 degree arc to one of 11 positions. Simultaneously two other levers are pulled down in patterns to tilt the ball up or down to four rings of characters. 

I found that the mechanism for the R5 selection was sticky and working erratically. That is, we can either see the typeball rotate as it should in the positive direction which is what R5 selects, or by its absence cause a negative direction spurious rotation. With the same selections on the other levers, I can see either a -5 rotation or the ball remain in the idle position, but the sticky mechanism causes the R5 selection to be missed in many cases. 

I had to locate the sticking part, a tiny lever pivot deep inside the machine that is the latch which keeps R5 from activating unless the solenoid releases the latch due to an R5 selection. The latch is not being pulled back to block the R5 lever movement in spite of the spring that is attached, because of gumming in the pivot. Oil loosened the old lubricants and my tools gently rotated the pivot until it was moving freely. 

Having the rotate and tilt tapes properly installed it was time to work through the adjustments to be sure it will print well. It was going along reasonably well until I noticed that the character selection latches aren't relatching correctly. This leaves the typeball partly rotated, not back at the home position. 

This may not happen under power and only while hand cycling the machine, because I do see that the next print cycle completes the resetting before the new character is latched in. I compared it to behavior of the 1053 that came on my 1130. My typewriter does fully reset when hand cycling. 

I reattached the cords that wind up the mainspring as the carrier is pulled to the left margin by a carriage return operation, then pulls the carrier to the right for space and tab operations using the power in the spring. These are two cords that wind around drums on the same shaft as the mainspring, one side letting out the same amount as is wound up by the other drum. I have to figure out how to wind the spring and tension the cords in order to complete this task.

I also discovered that some levers used to trigger the carriage return were gummed up. After I freed them up the CR button would reliably shift the mechanism into power return. This activates a clutch to turn the mainspring shaft using the constantly rotating operational shaft, drawing the carrier to the left. When the carrier strikes the left margin setting it pushes the margin bar leftward to release the return mechanism. 

This typewriter uses is a high speed rewind feature to reduce the time to return across the line. To decelerate the carrier, there is an air piston that stops the carrier from bouncing as it comes to a stop. 

I am still hunting for suitable tape to create a replacement color shifting tape that selects between the upper and lower half of the ribbon, which is a bicolor cartridge with red and black ink. This is 46 inches long,  0.105" wide and 0.003" thick. IBM used a plastic for the tape but I suppose as long as whatever I find is flexible enough and strong enough, it will do.