Friday, May 23, 2014

May 23, 2014 - My Nemesis, Part II

On a previous post, "My Nemesis," I tersely described the ailment of my 1937 Continental Model 35, and how its type bars do not rest correctly.




When looking at the relationships of the out-of-whack type bars, with all of the other pivots and stops and springs and the stresses imparted when pushing the type bars down, I decided to dig deeper.


I had heretofore gone through every point on the chassis of the machine to look for adjustments that might have slipped. All of these screws have no room for adjustment, they are precision located and lock their respective member in its exact, intended location.





When the raised type bars were pushed down, the lower edge of the segment would move slightly toward the front of the machine. Was this flex due to a crack? How does one look behind the segment? There's only one way I knew of, so stripped down she goes...



No cracks here (picture taken B.C. - Before Cleaning - I might add! :) )

I removed all of the type bars from the segment and removed the segment. I inspected the cast cross member that acts as the segment support... no cracks visible.

Of all the pieces that stressed and moved when pushing down on the raised type bars, the main, cast type bar cross-member was my next suspect.



Again, having no adjustment possible in the mounting of this cross-member, and seeing no visible signs of stress fractures ... what next?

When I would push down on the cross-member and the type bars would drop, I also noticed that the bell crank portion of the type levers that extend from the pivot of the cross-member, toward the keys, would rise and fall. This could be impacted by the height of the keys in their resting positions .... and I also noted that the highest type bars were the furthest row of keys (yxcvbnm,. -- being a QWERTZ keyboard).

I then looked at the various places where key height might be adjusted, and decided to remove the front plate with the slots through which the key bars protrude - they all rest at the top of the slots on this cross-bar:




I first loosened the four mounting screws for this cross-bar, but there was no adjustment possible. I then removed the four screws, and POP ... the crossbar jumped about 1/8" upwards and guess what happened as a result...




Okay, so now what? There is no vertical (or other) adjustment possible in the mounting position of this bar ... so what about the rest at the top of the slots?

Well, here's the rub. There is a plate at the top and behind of this cross-bar, where the key levers rest. There is also a rubber sheet that the plate holds in place, to cushion the levers when they reach the top of their travel.

The top bar of this front panel is riveted in place:




This plate, which I had hoped was adjustable, does not appear to have room to play:



I always try to find root-cause ... the "why" behind the issue, and in this case I can only point to this key bar rest as a suspect, not the cause... and that is because I can see no evidence of damage or change. This stop does not appear to have play for adjustment, and the change would have had to have been in the downward direction - yet there is not visible sign of a bend or stress.

So it's back on the bench with a giant question mark hovering over it. :-( Ideas?



11 comments:

  1. Sadly I haven't any idea. Hope it ends well though. :)

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    1. Thanks. So far, knowing what I know, seeing what I've seen, and experimenting where possible - this makes no sense to me. This is a machine that I REALLY want to be in working order.
      Also, in the process of tearing her down, the sad state of the rubber rollers became apparent. They must be recovered, they are *that* bad. Being a wartime machine, I am guessing that the rubber available to these tertiary industries was probably far from prime stock.

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  2. I wonder how this could have happened. An error at the factory seems unlikely. I sometimes just have to go "huh?!"

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    1. Add to this that the machine was bolted securely to the case bottom.

      Picture holding the chassis up with both hands, with your thumbs facing each other almost touching under the machine, with your finger tips up and over the sides of the machine -- and then if you pull down with your fingers while pushing up on the underside of the machine with your thumbs - this force also causes the type bars to drop.
      Yeah. "Huh!?" :-/

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    2. I've seen this problem on a couple of other Continentals for sale online and I always assumed it was some kind of deterioration of the segment or one of the segment-like pieces like with Merz (look it up on oz.typewriter) that caused the typebars to be frozen in place. You'd think with all the digging into it that you've done the problem would be known by now… :/

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  3. Well... at least the keys got nicely cleaned. They look really good!

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  4. Brian, a bit of a tricky one and with-out actually getting my hands on it would really only speculation from here on. My first impression would be that the typebar rest pad was way too low but you seemed to have ruled that one out pretty quick. My other guess would have to be the upper rest position of the key levers. And I think that you noticed that when you loosened that key lever frame. I know it would be a real bastard of a job, but can you see underneath that frame? what I would be looking for would be some kind of rubber or fibre rest. The rubber rest, if it exists, could be perished and so malformed as to alter the upper movement as the key levers come to their rest position. In a more practical sense, noticing that you said there are no elongated slots for any adjustment, I would be making some. At the end of the day, we have gotta fix the machine! Just a little tip, if you ever want to take out typebars, I would get a block of wood and drill as many holes as required so that you could put your typebar links in their proper order and avoid any further confusion and stress.. I would also point out that this is the machine that Hitler's secretary used when she was typing his last Will & Testament.
    I hope that I may have been of some help....

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    1. John, thanks for taking a look. I do think that changing the rest height is he "fix." I've looked at other possible adjustments like a shim under the segment, and that would cause too many anscilliary problems (like ring & cylinder relationship).
      I did get to one of the screws that holds that rest strip in place, and that strip is thin spring steel, with a pliable strip beneath it. I tried to remove the cross bar, but it's not coming out without dropping the key bars :-( I have all the type bars reinstalled (I used another wire, clamped so that it stuck out and up, and I slipped each type bar onto it as it was removed, thusly preserving the order).
      The next foray into this problem looks like I have to drop the key bars in order to remove the cross bar.
      Thanks for your time and consideration, John. I appreciate the advice and your keen eye. :-)

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  5. It seems something has moved out of position, effectively shortening the linkage between the keylevers and the typebars. I would have to examine the exact linkage design to see what has changed. Could it be the segment has moved rearward somehow? The clue is you mention the segment moves slightly forward when the keylevers are pressed. This should not happen.

    Clark

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    1. Clark - my apologies. I've been neglectful of the comments, and just saw yours. I would absolutely agree that it would seem that something has moved ... and that's where I am stumped. :-) I completely disassembled the segment and inspected it and its supports. I cannot see/could not see where something is out of whack - but that said, it only needs to be 1/16" out of spec for this to happen. I think it was dropped in the case - even though it was very securely attached to the case, and the case shows no signs of damage. Either that, or someone stepped on top of the machine, squishing its innards. I do not know. I will likely have to have a real pro take a look at this baby. It's otherwise spectacularly preserved.

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