Succeeded with print escapement and space function adjustments!

INTERACTIONS OF PULL ROD AND ESCAPEMENT TRIGGER ECCENTRIC STUD

The eccentric stud moves the claw, the escapement trigger, thus the clearance above the torque bar tab changes. These are not sequential adjustments as the manuals present them. Instead, they interact so that one must iterate changing one and then the other until the combination is found that reliably restores over the torque bar tab when a print cycle is done, but also reliably trips the escapement pawl out of the rack and reliably pops off the tab to ensure the action is a single column movement.

I figured out a technique to adjust the eccentric which involved marking the screw for the initial position and then turning to predetermined rotations. The screwdriver had to hold the screw from turning at this point while the nut on the back was tightened. As before a large screwdriver holds the escapement lever down so the eccentric screw is exposed. 

SUCCESS ACHIEVED

For a while, I would get print escapement working but not space, or get space working but not print escapement. Eventually I realized that a torque bar backstop adjustment was also involved and that was the key to success. The machine now reliably moved a column after print cycles everywhere across the print line. 

OPERATIONAL CLUTCH DRIVEN SPACE MECHANISM ADJUSTMENT

Because the lever that triggers an escapement is set up well, the adjusting screws can do their work. When the left operational clutch is triggered by the Space lever being released, it pushes a vertical lever in the rear of the machine under the bail that moves down then up during the clutch cycle. The space lever is released by either the Space pushbutton on the front of the unit or the solenoid attached to it being energized. 

The vertical lever rotates an arm downward, with an adjustable screw making contact with the main lever for print escapement. Moving the screw up and down determines how much the main lever moves when the operational clutch operates. 

Rear adjustment is for space function

The goal is the same as with print escapement, having the rest position of the claw .008" from the escapement torque bar tab when the space function is not operating. Then the movement of the lever should be sufficient to trip the escapement during a space function. 

Maddeningly, settings that work are very very narrow ranges of the adjustment screws. I found a set of adjustments that worked for the space function but when I tightened the locknuts down, it no longer worked. 

I found a happy point for the settings which reliably moved the carrier one column right whenever the Space operational clutch was tripped. This meant that I had the two means of triggering an escapement - the print cycle pull rod and the operational clutch mechanism - both functional. 

The upstop had to be adjusted after both of these, since you move it out of the way when making both of these movement adjustments. With that done, the typewriter should be adjusted properly for spacing. 

VERIFICATION- BOTH MOVING THE CARRIER ONE COLUMN TO THE RIGHT

I did a hand cycle of printing at the left, middle and right side of the machines carrier range to verify that we had a good single column movement after each print cycle. The SPACE pushbutton with hand cycling tripped the operational clutch and moved the carrier one column to the right. The solenoid was manipulated to trip the operational clutch and the carrier again moved one column to the right. I did the SPACE button test at the left, middle and right of the carrier movement range. 

REVERIFYING CARRIER RETURN SINCE I HAD TOUCHED IT TO FIX THIS ISSUE

The adjustment I made to the carrier return latch mechanism allowed the escapement torque bar to sit upright in its rest position, rather than partially twisted. Another part of this adjustment ensures that the escapement torque bar is turned far enough to completely pull the escapement pawl out of the rack during return operations. 

I checked that the carrier return happens without any sound of pawls bouncing over rack teeth. Everything is ready to move on to the last adjustments, where I get character selection dialed in for reliable printing. 

Still battling print escapement adjustments

PRINT ESCAPEMENT FINAL ADJUSTMENT

The filter cam with its one setscrew is nearly inaccessible as it sits at the idle position of a print cycle. 

Filter cam with setscrew under heavy aluminum block

Filter cam buried under all this hardware

Once the torque bar was upright, the eccentric was set up right and the cam on the filter shaft was turned to its proper position, the major remaining step for adjustment was to play with the length of the pull rod until it reliably triggered a one column movement after each print cycle. 

The goal was to have about .008" clearance from the claw to the torque bar tab when the filter shaft cam is at its low point between print cycles. The pull of the rod should move the claw down enough to trip the escapement torque rod. There is a limited range of movement of the pull rod thus this has to be very carefully set up to work properly. 

Pull rod from filter cam at top to lever arm at bottom

pitted main lever across bottom of view

Escapement trigger (claw) at torque bar tab

ADJUSTMENT OF PULL ROD HAS HIDDEN ADJUSTABILITY

The manuals all say to adjust the length of the pull rod. The obvious method is to remove the clevis where it attaches to the filter shaft cam lever, turn the clevis half turns to lengthen or shorten the rod and reattach. 

However, the range of correct operation is very narrow and sometimes one side of the half turn is too short and the other side is too long. It was while looking at my parts from the donor machine that I noticed that IBM very cleverly used two different thread pitches on the two sides of the pull rod. 

That is, the clevis on the cam side is coarser pitched and moves more per turn than the clevis that hooks to the escapement lever in the rear. By turning the rear clevis one can get finer control over the length! 

Never mentioned in any of the many IBM service manuals nor in any YouTube video, but an important capability. I used it to set up the pushrod for the maximum movement of the claw (escapement trigger) while still restoring over the torque bar tab when print cycles are at idle. 

ESCAPEMENT TRIGGER ECCENTRIC ADJUSTMENT IS THE KILLER

The escapement trigger (claw) moves on a stud that is eccentric - by turning the position of the stud, the latch sits higher or lower and pivots away from the tab torque bar tab differently. It too is an adjustment with a narrow range of settings that work. 

Eccentric stud on the donor typewriter claw

The challenge is in adjusting this part. The screw head for the stud is buried inside the frame and only visible through a small opening when the escapement lever is held twisted downward pulling the claw downward. The other end of the stud is a nut which is a bit more accessible but wrenches can only move a few degrees at a time because of other parts blocking their swing. 

Claw and eccentric stud nut

From the picture above, you can see a few things. IBM went with a double claw on the 1053 compared to the part in the picture above it. Presumably the wider contact area allowed the 1053 to rack up many more hours of operation without wear than a regular Selectric typewriter. You may also see that the other side of the eccentric stud is up against the inside of the power frame and surrounded by many parts for indexing, carrier return and other operations. 

This again introduces the classic problem - not enough hands - when making the adjustment. The escapement lever has to be held down in order to pivot the escapement trigger and its stud low enough to be (barely) visible through a small opening in the side of the machine. The lever and the eccentric nut are accessed from the rear, while the stud screw head is accessed from the side. 

Turning the nut to loosen or tighten it also rotates the escapement lever, thus one has to hold it twisted for access to the screw but also hold it from moving up or down as you tighten or loosen the nut. The screw must be turned with a screwdriver through the narrow side slot. 

Once you believe you have the stud rotated to a good candidate position, you have to tighten the nut to lock it down. That means continuing to hold the escapement lever down, holding the screwdriver on the screw head, turning the nut with a wrench, stopping the stud screw from rotating the screwdriver, and blocking the escapement lever from moving up or down from the wrench torque. 

I wedged the escapement lever down with a big screwdriver, which relieved me of one hand's activity, but that doesn't hold it when torquing the nut so that still needs a hand or finger. Screwdrivers that can fit into the small opening and the slot on the stud are tiny and very hard to stop from rotating. 

This is where I kept failing before I ran out of shop time. I could not get the stud to any setting other than its lowest point because of all the rotations involved with the screw head, screwdriver and escapement lever as I fought to lock down the nut. 

UPSTOP ADJUSTMENT

There is an upstop that keeps the mechanism from bouncing too far upwards after activation, but that adjustment is super easy to make once the escapement mechanism works well. 

Challenges with adjustment of the space mechanism

SPACE MECHANISM ADJUSTMENT FAILURE

Whether requested by pushing a button on the front of the typewriter or by activating a solenoid, the typewriter does trigger a single cycle of the left operational clutch. It moves a lever under the bail that is moved down by the movement of the operational clutch, turning the rotation of the clutch into a single downward pull and release of the lever. 

The lever in turn is connected by a few linked levers to the trigger for escapement, so that it should trip the escapement torque bar just as the print escapement does. The movement was not large enough to twist the bar and release the escapement pawl. 

I worked with the adjustments and even tried substituting a longer screw for one of the adjusters, but even that wasn't satisfactory. I realized that I had to change the print escapement setup if I was going to be able to get the space mechanism working. 

HOW THE TWO SPACING MECHANISMS WORK AND INTERACT

The common core of the two mechanisms is a claw which pulls down on a tab on the escapement torque bar, slipping off the tab to ensure a short activation of the escapement pawl to give a single column movement. This claw is pulled down by the rotation of a bar shaped lever. 

Bar lever

Claw atop tab on escapement torque bar

claw pulls off the tab

Remember that the escapement torque bar runs across the back of the machine just behind the carrier. When it rotates the bottom edge pulls the escapement pawl out of the escapement rack teeth. Since the claw pulls down but immediately pops off the tab, the pawl is only pulled out for a very brief period. It is long enough that the mainspring begins pulling the carrier to the right since the pawl is no longer holding in the rack. 

Because the torque bar flips back into its idle position rapidly, the pawl is released and slides into the next tooth of the escapement rack, halting the movement to exactly one column. Thus, we need the bar lever to move enough to pull the claw down off the torque bar but twisting the escapement torque bar in the process. 

There are two ways that the bar lever is rotated to pull down on that claw. One is a pull rod coming from near the front of the machine, the other is a complex set of levers that move when the operational clutch powers a space request.

The print escapement rod will be pulled, rotating the bar lever, at the proper time during a print cycle. A filter shaft turns during a print cycle and on it is a cam with a roller that drives the pull rod for print escapement. The cam is shaped so it yanks on the pull rod when the type ball has already struck the page and is returning to its rest position. The carrier can now move without smearing the typed character. 

If a solenoid activation or the front 'space' pushbutton triggers the operational clutch for space, the motor power spins the clutch through 180 degrees. A roller on the clutch surface moves a bail in a down then up cycle through that rotation. The space request pushes a space activation lever lip under the bail so that the space activation lever is pulled down and then released upwards as part of the clutch cycle. 

The space activation lever connects to the bar lever, with two adjustable screws that should cause the bar lever to yank the claw of the common escapement mechanism I described above. It is a complicated set of pivoting parts designed to push down on the bar lever when a space request is made but not stop its movement by the pull rod during print cycles. 

space activation lever pulled down by bail

The partial plate shown on the right of the diagram above is the plate that houses the mainspring and drums. 

mainspring plate holds adjustment screws

one adjuster shown, second pushes on top tab in front of the one shown

As the 1053 is adjusted now, the bar lever ("escapement trigger lever") is already partly rotated while the pull rod is in its idle position, so that the print cycle turns it a final amount to operate the claw ("trigger"). Because of that, the adjustment screw from the spacebar latch lever doesn't adjust far enough down to impart enough rotation of the bar lever to trigger a space. 

Because of the interaction between the two mechanisms, I couldn't get space working. I had to go back and completely reset the print escapement settings. What was necessary was for the bar lever to be nearly completely unrotated while the pull rod is idle, but therefore its relatively small rotation as the rod is pulled has to be enough to move the claw to trigger the escapement torque bar. 

STARTING OVER AND CHECKING EVERYTHING

This took more time that it would seem, in part because there is an interaction with some carrier return adjustments that are, as usual, totally unmentioned in the adjustment manual but really important. All in all, I put in about four hours work on this. It included a disassembly of the donor machine to see how all the parts work and several comparisons to my working 1053. 

I changed a CR setting to let the escapement torque bar sit more upright at rest, then tried different settings of the trigger eccentric screw before I got to a state where, with the escapement trigger lever (bar lever) basically flat and unrotated, the trigger (claw) was just over the tab on the torque bar. 

I then adjusted the filter shaft cam so that it was positioned properly. The objective is for the roller to have just reached the low point on the cam at the rest position of a print cycle. The cam was not right and I had to loosen its setscrew and move it to the desired spot.

The setscrew is in a very inconvenient location where tools can't reach it at its proper position. I had to work out a method that involved releasing the pressure from the roller, after loosening the setscrew in mid print cycle. I could then rotate the cam by hand while the machine was at the print cycle rest position, getting it at the ideal spot. 

While working on this method I discovered that a spring was missing, that should twist the lever with the roller so that it follows the cam. I grabbed a suitable spring from the donor machine and attached it so that the escapement roller will work as intended.

Removing the pressure on the roller let me hand cycle a print cycle until the cam with its loose setscrew had moved out to a spot with reasonable access, then I tightened it down. I verified that it was correct, if you back up from the rest position the roller immediately moves upwards, so we are at the beginning of the low zone. This gives maximum time for the type ball to print a character before we release the escapement pawl to move forward. 

I ran out of time in the shop at this point. I expect that I just have to adjust the length of the pull rod so that a print cycle will always trip the escapement torque bar. The adjustment screws for the space mechanism are in much better position with lots of range available. Once the print cycle escapement is verified I can adjust the space mechanism and hopefully finish the job. Perhaps another hour or three of fun ahead. 

Successfully adjusted carrier return, tab, current line pointer and print escapement

CARRIER RETURN ADJUSTMENT

Although the carrier return was working properly as far as moving the carrier back to the left margin, the escapement and backspace pawls were slightly dragging across the rack teeth. Not only does this make an annoying noise, it can wear away the pawls and teeth. 

As part of the carrier return operation, when the mechanism is latched into the operating state which will remain until the left margin releases the latch, it should twist the escapement torque bar to move the pawls far enough away to clear the rack teeth. The solution was to adjust an eccentric bolt that was part of the latch mechanism. I soon had the typewriter quietly moving to the left during the carrier return, which was the objective for this adjustment. 

TAB ADJUSTMENT

Tab was mostly working properly, but when I would hit tab with no tab stops set before the right margin, the carrier stopped but did not unlatch the tab operation. That would foul up carrier return activation so I had to fix this issue. 

I discovered that the repair I made to the right margin lever, the one that been broken, interfered with the homemade current column pointer I fashioned to replace a missing part. With the interference removed, the carrier properly unlatched when it reached the right most column. 

REPLACEMENT CURRENT COLUMN POINTER ADJUSTMENT

I had to widen the holes in the aluminum part I had created so that it could mount a bit higher on the carrier. This let it clear the right margin lever, which had a metal bracket epoxied to its top as part of its repair. 

With the point moved up and the bends altered slightly, the pointer now clears the margin levers and properly points at the current column so that it will be visible in the plexiglass window when the front panel of the typewriter is installed. 

PRINT ESCAPEMENT ADJUSTMENTS

Moving the carrier a space to the right involves twisting the escapement torque bar out of the way but letting it rapidly return upright. The escapement pawl moves out of the rack, the mainspring pulls the carrier to the right, and the released escapement pawl drops into the next tooth of the rack ensuring a single column movement. 

A pullrod was adjusted as well as an eccentric bolt that sets up the activation lever to snap off the tab of the escapement torque bar, giving that short activation that guarantees the single column move. That eccentric bolt has a screw head which was hidden inside the frame and barely accessible only when partially activating the lever by hand. The other side has a nut and is easily accessible from the rear of the typewriter. I managed to get this set properly after a bit of fussing. 

I had this working well, so that I could move on to the other mechanism for spacing that uses an operational clutch to pull down on a lever when triggered by the Space pushbutton or the space solenoid. This was not tripping the escapement torque bar and I hadn't achieved good operation by the time I was done for the day. 

Done adjusting the paper feed mechanism, adjusted cycle clutch as well

READJUSTED THE PLATEN POSITION TO GET THE FEED ROLLERS CORRECT

I figured that I won't make any changes to escapement rack positioning at this time, simply get back to where I had feed rollers that pressed on the platen and released properly with the paper release lever. From there, I would deal with the carrier movement issues and then get back to the remaining adjustments and tests on the machine.

While I couldn't get the front rollers completely in place, the gap was only about the thickness of a punched card. I inserted some paper and realized that the paper feed holds the pages well and feeds properly as it is, so I am closing the book on this adjustment and moving forward. 

CYCLE CLUTCH FINAL ADJUSTMENT

The print cycle clutch is a fundamental mechanism that I wanted to get just right. It is a clutch type widely used in the typewriter where a coil spring rotates around a metal drum, with one end of the spring fastened to the motor pulley which is always turning and the other is either loose or held by the clutch actuator.

While the one end is loose, the spring coil returns to its natural shape, tight on the inner shaft, and thus will turn the shaft. When the end is held, however, the spring coil unwinds to a looser coil and the inner shaft slips around without disturbing the coil spring. Thus, holding the end of a spring stationary will keep the clutch from activating and turning. 

The outer cylindrical piece that fits over the coil spring, with the spring sandwiched between the inner shaft and the outer cylinder, will rotate with the loose spring unless it is held by a tab that projects to hit one of two steps in the outer surface of the cylinder 180 degree apart. The tab is the cycle clutch release arm, normally it is jammed against the tab on the outer cylinder keeping it from rotating. This opens up the coil spring so that the inner shaft is not forced to turn.  

When a print operation is to take place, the clutch release arm is pulled away momentarily, the coil spring tightens up and the entire assembly now turns including the inner shaft. A cam and roller on the outside forces the clutch release arm back so that it blocks the next tab, stopping the clutch after exactly one half turn. 

The adjustments for the cycle clutch involve three things. First, the end of the coil spring that is held or allowed to turn is moved around the circumference of the cylinder so that the coil loosening takes place just before the end of a cycle, with the momentum of the moving pieces producing the last few degrees of rotation.

The clutch must stop so that a check pawl drops into a slot on the end of the inner shaft. The two slots are the idle positions of the print mechanism. The clutch should come to a stop with the pawl just able to fall into the slot. For that purpose, the clutch cylinder has overthrow stops that let it bounce slightly past the stopping point from momentum, ensuring the pawl engages to hold everything in place.

I want the adjustment for the coil spring slipping at the end of a cycle to give me the solid check pawl engagement. At that point I adjust the overthrow stops that allow that small amount of excess rotation as the clutch stops. One Bristol head bolt for the slippage and two screw adjustments for the overthrow at the two stop positions 180 degrees apart. 

The adjustments were a bit tedious but eventually I had this dialed in perfectly. The benefit is that it corrects an error that existed up to now, where the ends of the tilt and rotate selection levers had not popped back under the bail at the end of a print cycle. They do now, everything looks good to move on and finish up the other adjustments. 

Adjusting the paper feed mechanism - part 6 and continuing

PAPER RELEASE MECHANISM ADJUSTED

I figured out a method that only need four hands, actually two hands using more than one finger independently on each hand. I was able to adjust the paper feed rollers and paper release so that it worked perfectly. See the movie below of this moment of success before the world got dark and ugly again.

SET PLATEN TO SPEC AND SUDDENLY THE FEED ROLLERS ARE OFF AGAIN

I had some resistance of the carrier moving across the line, which I believed to be due to the platen position so I went through the procedures to set its height and distance again. Low and behold, the darned feed rollers lifted off the platen and were back to the bad old behavior. 

  Curses

WHAT IN THE H*** HAPPENED TO THIS TYPEWRITER BEFORE I GOT IT?

It appears that all the parts of this typewriter were misadjusted in some weird way before I got it, with compensating maladjustments applied that led to the next issues. Likely that is why the paper feed mechanism was finally removed.

I think that the fundamental position is wrong - the escapement rack must be at a given distance from the print shaft and then the carrier adjusted to ride at this spacing. The rack is definitely NOT at that proper distance and I think the carrier rollers were tweaked to fit the current situation. 

With the carrier and escapement in the wrong place, the platen was apparently forced to an incorrect spot to still type, but the cascade of issues multiplies from this deed. I might have thought that this typewriter was tossed out of a moving vehicle or dropped several stories, except there are no signs of damage or scrapes. However, it is about as far out of adjustment as if it had suffered serious trauma. I suspect the traumatic event was human intervention. 

Each time I think I have this almost wrapped up, the other shoe drops and I find more issues. There are no procedures set up to put a Selectric together from scratch and adjust everything in some ideal sequence. Frankly, a typewriter that was out of adjustment like this would have been returned to the factory and a replacement ordered by the repair staff. Since the factory and the parts department no longer exists, this isn't an option here. 

Adjusting the paper feed mechanism - part 5

GOT IT! FEED ROLLERS AND THE PLATEN NOW MATE PROPERLY

I ended up loosening everything on the machine and disassembling quite a bit, before manually moving all the parts around until I could get the front rollers to come up and touch the platen. After that, I put parts back on and made adjustments, checking each time to be certain that paper feed the rollers worked properly 

READJUSTING THE PLATEN POSITION AND FEED ROLLERS

I set the platen using the Hooverometer to determine its height above the escapement rack and then to set the distance from the print shaft to the platen for the front-back positioning. I might have to tweak the height later when I am printing characters. If the platen is too high or low, the the bottom or top of a character will be faint. 

The feed rollers were adjusted to the specification, which is that with two punch cards inserted between the front rollers and platen, the rear roller should have a tiny gap to the platen. After going through all the settings, I am very pleased with the operation of the paper feed mechanism.

WORKING ON PAPER RELEASE MECHANISM BUT NOT DONE YET

Another lever on the typewriter allows the operator to release the feed roller pressure in order to feed in new paper or to move paper around easily. That lever has an eccentric cam which twists the release rod. On the rod are a number of adjustable tabs which can press on the spring loaded roller levers to move them away from the platen. 

The goal is to have a small gap with the rear roller when the release lever is operated, but achieve regular pressure on the rollers when the lever is not turned. The setting procedure sounds simple but in practice it is frustratingly difficult.

This is because the tabs on the release rod are fastened with a bristol opening bolt and nut. The nut is not held in place thus you need one hand to turn the bolt and a second to hold a wrench on the nut. But wait - there's more. The levers must be moved forward enough to achieve the gap - one hand to move the lever and another hand to test the gap with a feeler gage. 

Then, when the lever is at the correct position, the tab has to be moved up flush against the lever - another hand. The release rod can move away from the surface of the eccentric cam on the lever, so you must hold the rod pressing on the cam - yet another hand needed. 

If you are following along, that is six hands needed to adjust one of the four tabs. Fortunately the tabs do not have to be adjusted simultaneously - a serial adjustment  process works fine. Next time I am in the shop I will do battle again until I get the paper release set up properly.