Farm Collector

Tinkering with Messrs. Springer, Woolf, Etc.

1102 Box Canyon Road, Fallbrook, CA 92028

This yarn is inspired because of a happenstance at two
consecutive Old Time Thresheree shows I happened to attend in the
not-too-distant past. Everything was going along hunky dory with
all the exhibitions in full attractive demeanor, right up to the
parade sequence, when along labored a fine old steamer with the
most terrible case of asthma that I have ever heard in my life! She
was pounding on only one end and, had I been blindfolded, I would
have taken her for one of those old 1910 Titan gas tractors that
could really shake the earth as they rolled by. As this venerable
specimen passed our reviewing stand, it became at once evident
wherein all the difficulty arose. This fine animal was equipped
with a Woolf valve gear and also a rocker shaft to increase the
valve throw beyond block drive. As she banged her way along the
route leftward in front of us, it became apparent that this rocker
was being exercised by an extreme over-length in the adjustment
between the rocker and the block drive. This caused the upper
section of the rocker to oscillate too far rearward, with the
result that only the head end of the cylinder was receiving and
exhausting steam; the rear port hardly being uncovered at all which
most detrimentally transformed her into a single-action job not at
all intended by the manufacturer. A monkey wrench and ten minutes
should have brought her back into the ‘ball park.’
Actually, a good steam man can set a valve very closely by simply
adjusting the valve travel in one direction until it is clearly
evident that she is coming short on one end; then adjusting travel
in the opposite direction until the same unbalance becomes evident.
By counting the turnbuckle turns between extremes, and splitting
the difference, it will be found that operation is way above
reproach. This, of course, is a quick and dirty method to be
resorted to in the field in order to keep the crews busy until
after closedown when the engineer’s duties seem to never
end.

But now, to digress a bit in general on valve gears, which,
after all, are about the most complicated element of the old
steamer other than the injector (which, since it appears to have
worn out and will not respond to cleaning any more, must be
replaced) and the force-feed lubricator (which at most may require
cleaning to remove a bit of debris from under the discharge valve,
as evidenced by the fact that it has been pumping oil all day over
the sight feed but the reservoir is still full!).

Ever since Watt discovered that a cam or eccentric could replace
the labors of an attendant who was originally required to operate
the valves on the New comen pumping engines, and engines became
double acting, the subject of proper valve setting also became a
subject to be mastered by the operating engineer. Now, today, we
may take so much for granted. If it be a simple mill engine, all
that is required is to equalize the valve travel over opposite
ports; then adjust the eccentric for the desired lead. If a tram
and marks have not already been provided, it requires but removal
of the valve compartment cover and a few course measurements.
Rocking valves are a bit more tedious, but true to form while going
to Stevenson link motion is a repetition of the first case above
requiring only that each end of the link be matched in accordance
with direction of motion. With ‘open’ method of link drive
as was common in locomotive practice, it is interesting to note
that these old locos would run at speed in either direction with
the ‘Johnson Bar’ hooked up to true center (the ports
became slightly uncovered to inlet steam at dead centers).

But, eventually, and originally in marine practice, along came
the development of the ‘radial’ type of valve gear. There
are quite a raft of patents applicable to this Rube Goldberg
contraption; but they all accomplish the same duty with the same
effectiveness. These gears soon became applicable to railway
practice because of their accessibility, and were competitive with
the Walschaerts type of outside valve gears (which later were often
mis classed as of radial type). The Baker and Southern were the
only two radial types of locomotive gear in extensive practice. As
Stevenson dropped out mostly because of its inaccessibility, Baker
and Walschaerts absorbed most of the field. However, Young (who
also designed a rotary locomotive valve) did find a small
installation for a valve gear which resembled Walschaerts, except
that, instead of utilizing a crank drive for the link off the main
driver, it utilized the cutoff drive from the crosshead on one side
to not only furnish that function but also, through a short
connecting link, drive a rocker shaft that extended across the
locomotive frame and supplied drive for the valve on the opposite
side of the locomotive. All valve drive functions were thus derived
from only crosshead source.

It is well to point out here that, if a single fixed eccentric
is to be utilized on a reversible engine, it must necessarily be
set at 90 degrees from crank position. But an eccentric (alone) set
at the position does not allow setting at proper lap of the valve.
Hence, since proper eccentric lead is in the neighborhood of
120-135 degrees, an auxiliary motion is required. This is
ordinarily supplied by the auxiliary drive off the crosshead. If
you recall your plain geometry, the resultant vector derived from
two other vectors 90 degrees apart, may result in a final vector
anywhere between zero and 90 degrees (depending upon the respective
length of the combined vectors). By utilization of a rocker
linkage, the resultant vector may become one of 90 to 135 (or more)
degrees. Thus, with Walschaerts, we combine 90 degrees off the main
crank throw with that of zero (or 180) degrees off the crosshead
and wind up with our desired 120-130 degrees.

A unique scheme of utilizing a single eccentric for both forward
and reverse action is found in the Russell, which shifts the
eccentric from +120 degrees (or whatever may be necessary) to -120
degrees. This gear may also be ‘hooked up’ as with any
other motion EXCEPT that of Marsh-bless his heart. With the latter,
one cannot work his steam expansively except through governor
action, which is generally regarded as uneconomical. For this
results in ‘wiredrawing’ of the steam; in which case
working pressure is reduced through an orifice without
accomplishing useful work. For, when any gas is expanded through
throttling action it becomes cooled according to fitting
‘laws’ of thermodynamics. And while on the subject of
Russell, with its double-ported valve, it must be realized that
even though twice as much (inlet) valve is uncovered per lineal
length of motion, there is yet wiredrawing near opening and closing
of this port. Double-porting is irrelevant to the exhaust port; –
that end has to take care of itself. And, while we are on the
subject of Russell, it may also be noted that this firm’s
method of tandem-compounding was regarded as superior to Mr.
Woolf’s in that each cylinder had its respective valve and
steam chest; which not only avoided long wasteful steam portages
from high to low pressure (there can be no power developed through
expanding steam in long passages between cylinders) but also
allowed the low-pressure valve chest to act as a receiver as
utilized in cross-compound cylinders. I have diverted a bit off our
prime subject here because I have been rather unable to submit
written matter more often; and have thus been putting my thoughts
into words. Please excuse the folly. Back to gears!

I was going to ask ‘Where does the nomenclature RADIAL come
from with respect to steam engine valve gears?’ Well, if we
refer to some of the old cyclopedias and patent records regarding
valve gears, we will find that at some early point in time marine
engineers must have deplored double eccentrics and linkages for
every cylinder on their old (already cumbersome) multiple expansion
engines. So some ingenious chap who was really quite smart at the
time devised a (movable pivoted) swinging linkage which, by means
of changing the pivotal point of the (radius) link could cause the
valve motion to change 180 degrees. These old marine engines were
of vertical type, of course, to fit the ship’s enclosure. But
the gear found widespread adaptation in both railroad and traction
usage, both of which utilized horizontal engines. There were many
variations found in this gear; some of which appeared to do hardly
more than change a point of support or suspension. But, like many
ideas, some of which were mechanically impossible (the Patent
Office could not have required working models in every instance for
the inventor) the variations found themselves protected for at
least seventeen years. And now, since this manuscript is framed for
the dear old steam traction engines, let me direct your attention
to Figure One, which I accomplished with an old set of drafting
instruments furnished with an American Correspondence School course
in electrical engineering way back in 1919 and which proved so much
over my pumpkin head, without a close instructor, that I was forced
to give it up rather pronto after having been coerced into paying
some $400 for it! I have used the set ever since; but it is
doubtful that I have derived $400 worth of usage out of it in 72
years. Anyhow, back to our first sketch.

This is a line drawing design layout for a genuine radial type
gear and is identical to that as employed on both my Monarch
double-cylinder engines; one of which is installed on Luellabelle
(see the cover of IMA, Nov-Dec. 1981) and the other, one of the
finest engines you ever could see, is off their traction, and is
now on the exhibit steam line over at our fine museum in nearby
Vista. The Monarch line was manufactured in Groton, N.Y. and
Luellabelle’s original (roller) came off line in 1925. But now
back to our Fig. 1 which is not drawn to design scale but simply
intended for illustration.

‘A’ is the crankshaft; ‘B’ is the crankpin
located at OUTER DEAD CENTER; and ‘C is the crosshead wrist
pin. Now, the central position of travel of the source end of the
RADIAL arm ‘D’ and the load end of eccentric strap
‘E’ is shown at ‘F’. As will be pointed out later,
‘F’ position is also the center of travel for the sliding
block in the later Woolf version of this original design.
‘G’ is the movable anchorage point (by the reverse lever)
for the Radial link. ‘G’ may thus be moved (in three or
four increments) to G-l, one direction of rotation for the engine,
or to G-2 for reverse operation. The displacement of ‘G’ is
usually accomplished by a large bell crank which is anchored at the
same position as ‘F’ and therefore is not shown on sketch
for simplicity. This arm must be the same length, center-to-center,
as ‘D’; otherwise (at center throw of the eccentric) the
valve would be disturbed from its present location. If it is
detected in practice that such slight movement of the valve is thus
caused, it is termed ‘slip’ and must be corrected as
described later.

Now, one remaining remark at this point. The anchorage for the
bell crank arm (which is hidden behind, and coincides with
‘D’, and is also the center of sliding block travel in
Woolf design) is usually mounted vertically above the crankshaft
(it is mounted below in Reeves design). However, it may also be
mounted ahead of the crankshaft line as shown, by the angle
‘X’. In any case (Case?) the angle ‘Y’ must be
preserved as 90 degrees; for, remember, we are keeping our
eccentric throw at 90 degrees from the crank throw. The right-angle
takeoff accomplished this, while the direct angle between crankpin
and eccentric is ‘in phase’ at zero degrees (except our
case of displacement through angle ‘X’). It is also called
to attention that, if a rocker arm is employed in the valve stem
drive, the eccentric might be mounted at 180 degrees from the
crankpin (or the position of the reverse lever made opposite).

Now, only one item remains for consideration; the takeoff for
the valve stem drive through the linkage arm ‘H’. This
fixed appendage T to the eccentric strap must be mounted to same,
in a dimension not only offset from the strap, but also at an
appropriate proportional intermediate distance between the ends of
same in order to provide the desired ‘lead’ for steam
admittance to the cylinder. It is seen that the resultant motion at
this point is a combination of both eccentric and the swinging link
‘D’ as it rocks up and down through the end points’
J’ and ‘K’ and through the arcs ‘L-l’ or
‘M, M-l’ according to direction of rotation of the engine.
‘N, N-l’ of course is the line of travel when the reverse
lever is placed on center if the crankshaft be rotated.

The working layout for extension T, the wrist connection to
‘H’ of which describes the oblique ellipse like path
‘O’ was originally determined by pattern layout, and really
did not present a serious task. Today, if such need were felt, its
layout, together with all other elements of such gear, would become
the product of a bit of computer manipulation through usage of
graphics and aid design software programs. And while I have been
struggling over ten years with these fantastic electronic
contraptions, I am not prepared as yet to tackle this sort of
problem.

While ‘O’ is rather an odd figure, it suggests that
steam distribution might not be the same at both ends of the
cylinder; and may not even yield the same available power from the
cylinder in forward motion compared to reverse. This is true; but
when we recall that distribution is measured in proportional valve
opening for corresponding points of piston travel, and the piston
travels further on the head end than the crank end for quarters of
shaft revolution, we can readily appreciate the value of an
indicator diagram when making a setup to realize the same amount of
cylinder power developed between both ends. At the Case factory
(and I suppose at others as well in the Good Old Days) all steam
engines were required to measure up to an excellent indicator
diagram on final test. Yes, the angularity of the connecting rod
and the ips-switching of valve gears play great antics. An article
on the first-mentioned topic was written by this author for IMA
several years ago; while a splendid article on forward and reverse
power was written in our same publication more recently. Please
don’t make me dig those editions out of my files right now.

We may now readily see how Mr. Woolf decided to modify things a
bit, by simply replacing ‘D’ and its supporting structure
with a grooved crosshead guide, so to speak; and placing a sliding
shoe within the slot way so as to move up and down in a fashion
resembling the arcs ‘L’ and ‘M’. To retain
similarity, both Case and Avery called attention to their
‘curved block’ in their advertising. However, it is my
belief that Aultman-Taylor and some other manufacturers utilized
straight blocks. If the RADIAL arm ‘D’ had been of infinite
length, then, according to geometrical precepts, the resultant arc
‘N, N-1’ for instance, would become a straight line. But
the utilization of a curved block affords more acceleration in
combination with the eccentric sweep, such that the two ends of the
drive, working in parallel, thus cause quicker valve opening and
closure with less wiredrawing of steam for which good feature
radial type gears are noted. However, ‘hooking up’ a radial
gear does not allow for advancing the valve action at a speed
similar to that rendered by the Stevenson link motion.

At this point, we might examine some of the quirks which should
be checked when examining valve setting to determine whether the
eccentric may have slipped or excessive wear occurred. This is a
one-two-three operation in that order. Referring to Figure 1, which
depicts a layout for the reverse head bracket, the block guide
shaft is in upper bore ‘P’ while the crankshaft runs in
‘A’. When the crank is placed on center as in Figure 1, and
the eccentric is at half travel (the angularity of the eccentric
may be accounted for similar to that of the main connecting rod)
and the reverse lever is rocked through neutral position, the valve
should exhibit no movement during this lever movement. If there is
‘slip’ in valve movement, it means that point ‘P’
in the upper bearing of Figure 2 has likely fallen due to wear or
mis adjustment. The remedy for this error is to adjust the shims
provided at ‘Q’ to raise or lower ‘P’ until minimal
slip is observed. (In Figure 1 this must allow the distance F to J
to equal that of F to K.) To digress a bit further at this point,
it must not be construed that, while the eccentric is at full
travel in Fig. 1, and the strap ‘E’ is at half travel
(point ‘F’) this should lead us to believe the valve is
also at half-travel. For the latter should be at ‘lead’
setting for the crank end of cylinder as shown. The lead is thus
caused by the offset in the strap extension T, which substitutes
for the lap-and-lead lever from the crosshead in the Walschaerts
type of gear. In fact, the two gears bear very close resemblance in
action, for, when the eccentric crank of the Walschaerts is at mid
travel, the piston is at full travel, and the lead lever just
uncovers the port at that end of piston travel.

Secondly, let us tackle Figure 3 which illustrates the linkage
between the reverse lever and the block guide. A turnbuckle or
other means should be provided at this juncture to allow for
adjustment such that, with the reverse lever on center, when
turning the engine over, the valve should exhibit the same closure
over either cylinder port.

Thirdly, referring to Figure 4, is shown a linkage adjustment,
in this case through a reverse rocker, between the eccentric strap
takeoff and the drive to the valve stem. It is simply an equalizing
turnbuckle (or other length-adjusting arrangement) which allows for
setting the full opening of one cylinder port to the same amount
for the opposite port. From indicator diagrams, it may be found
that a bit of ‘fudging’ is required for port opening and/or
lead to obtain a well balanced power distribution for both
ends.

The above procedures were also prescribed by that fine New
England trained mechanic who came to dwell in Oregon a long time
ago: Charles ‘Pop’ Arnold. And I am reminded to say that,
in those older days, we always looked to Rhode Island, Connecticut,
New York and Pennsylvania or New Jersey to find the best. We had a
splendid journeyman railway machinist when I was an ambitious kid
boiler maker and machinist helper on the C&NW in the Dakotas
whom I shall always remember: Ray ‘Yankee’ Cooke; like the
Rhode Island locomotive builder. Our chief boilermaker, Peter
Paluzak, also hailed from around the Polish center in New Jersey.
But after WWI, the cultural center of our country began moving
westward and it has never ceased to this day. Had the recession of
1920 never occurred, likely I may have remained in the railway
service through my active life. But, like the old saw goes,
‘Nothing changes like change’, and I have been spinning
ever since.

Hah, I just glanced up at one of the railway locomotive pictures
on the wall: a Southern lokey with their Joy radial valve gear. Its
unusual arrangement reveals the suspension linkage (as shown at
‘G’ in Figure 1) mounted horizontally above the cross head
wherein ‘G’ is slid back and forth by the reverse lever in
what resembles a curved second crosshead guide. There are so many
variations in this type of gear; but let no one confuse you that
Walschaerts is of this class. That old boy simply combined two
crank motions which were out of phase by 90 degrees to derive the
differential angle of drive as explained previously (it is worth
repeating). In the electrical-electronic field such combination of
vectors is utilized most extensively in demodulating color
television signals, changing digital to analog information,
etc.

Had our dear old steam locomotives not been superseded by Diesel
power, it is likely that the poppet valve designs which were cam
operated as driven by gearing (at that time being developed by
Caprotti, Italy, and Franklin, USA) would have resulted in making
automobile mechanics out of every chap who aspired to becoming a
steam engineer; for these locomotive designs would have been
carried over into our traction engine fields. They actually were
incorporated in the later stationary steam engine designs as
exemplified by Ames in their Uniflow engines-one of the closest
approaches to steam turbine efficiency.

Well, this brings me to the point where I am reminded that
another old Shanty Irishman once stated to me during an explanatory
discussion, ‘Now I have told you all I can about something I
know nothing about.’ At any rate, please do not call my
attention to some old steamer which is parading down the show path
with one governor ball missing, lest I may feel constrained to knit
another yarn. Of course, I am always appreciative of criticism
which begets more learning; so let any hailstones fly which may.
It’s all fun, you know.

So good going in there, you fine fellows; and keep those
wonderful relics huffing and puffing. See you there!

  • Published on Sep 1, 1991
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