[GreenKeys] Model 15 Mainshafts

[George B. Hutchison]

GreenKeyers - - -

The mainshaft on a model 15 is an item which should be removed and cleaned
separately when cleaning the typing unit.

The reason for this is that the mainshaft can be perceived to be a "small
world" within itself.

Let me explain...

The 15 mainshaft is hollow. Correctly assembled there is a central felt wick
which runs pretty much the length of the shaft. Additionally, there are
several cross-wicks which are located in the areas where the shaft has been
penetrated to provide lubrication for the spacing gear, the bail drive
arrangement, and a couple of other places.

The wicking provides a means of timed, continuous lubrication of those
components which are not affixed to the mainshaft with a screw.

A rough means of checking a mainshaft is to remove the plug and leather
gasket located at the drive gear end, taking a Plews or other pressure oiler
and using a shop rag for a gasket, pump #10 non-detergent oil into the
shaft, and observing whether or not the oil will come out of the small hole
which is in the center of the selector cam retaining screw on the selector
end. If oil comes out, then things might be OK. If you cannot see any oil
coming out, then chances are the mainshaft has heated up somewhre along its
length and caused the shaft to plug up.

The remedy for a plugged mainshaft is to disassemble the shaft by removing
all the pieces and drill out the mainshaft with a mainshaft drill, which is
about 1/8" diameter and perhaps a foot long. Drills similar to mainshaft
drills can nowadays be obtained at most hardware stores or industrial
suppliers. The current usage for long drills is for activities such as
burglar alarm installation. The cross wicks can be nudged out with a paper
clip

Teletype had a mainshaft wick kit for the fifteen which contained the
central wick and the small cross wicks. Chances are there are none
available. The model 15 will run fine without the wicks, but regular oiling
is required, and this can be accomplished by occasionally pumping oil in the
gear end until it starts to ooze out the selector end. It depends on how
many hours the machine runs between oilings.  Be sure you have an official
oil plug with fashionable leather sealing washer.

KCID in Caldwell, Idaho had a fifteen in a soundproof box right behind the
announcer. They would not allow PM visits, so the only time the machine was
serviced was after it burned up. The machine ran so hot that after it was
shut off and the box disassembled, it took about forty-five minutes for it
to cool before the screws could be loosened and the typing unit removed. It
was pointless to try and service the machine which had failed. Generally it
was full of red-rust (fret-corrosion) such that it would take four hours to
get it back in shape, and at one or two in the morning I was just not up to
spending all night working on it. I kept several spare typing units, and
they always got a replacement.

The KCID machine was lubricated with a 50-50 by volume mixture of 30 weight
non-detergent oil and STP (remember Andy Granatelli?). After the machine
heated up the STP kept the lubrication present. I could usually expect
another call from them in four to six months.

I will also repeat my periodic recommendation that the best grease you can
obtain for any teletype is Conoco Super-Sta. This is a #2 Lithium-based
grease which has a tackiness agent added to it such that it sticks very well
to any machinery. I have a tube of Super-Sta which I first used in Idaho
some thirty years ago, and it is still just fine. I use it to lubricate the
nose sprocket on the chainsaw. It can be obtained from most Conoco
distributors from the east coast to perhaps Idaho. Seems to me the price is
about $2.50 or so per grease gun tube. The avid teletype enthusiast can get
it in five-gallon pails.

KS-7471 Grease (official teletype grease) turns to concrete in about 3-4
years. I have a can of it which I guess I should send to Don House for his
museum. Looking into it it looks like the Edwards AFB dry-lake bed, all
cracked and wrinkled. Awful stuff.

Today's activity will be to go to Auburn and ship those items expected by
others to the extent I have things packed. Bob Camp and Roy Norris will be
getting their items on pallets. Gil Smith's goodies will be UPS, and I have
yet to find some rugged box or boxes for John Lawson's BRPEs. Interesting to
note that the weight of the picture tapes for Bob Camp is somewhere between
sixty and eighty pounds, and they fill five boxes. Good Luck, Bob!!

Larry, W7JYJ wandered off with several 28 typing units and motors, and a 28
KSR keyboard and typing unit, equipped with a 3-speed gearbox..

Jack Hart's pile is extensive as well, but may take another week before I
have it all ready to depart.

And so it goes.

73, folks...

George, W7TTY