Dodgeville chronicle. [volume] (Dodgeville, Wis.) 1862-current, 1870-06-24
Stearn's Patent Eccentric Head Blocks
for Circular Saw-MiIIs.

| GlCo Will Tedu IL CeIoluiiJ, nuu IL NV PoA
sonally interested himself, will call atten-
ton to it. To the casual observer it would
seem of little Importance but it is mat
ter of vital Importance to nearly everyone
in this country. Weuse the language OF the
inventor himself in describing this
great improvement in the manufacture OF
lumber. His invention was first patented
in 1855, and has been before the public for
fourteen years, and on the 18th of April,
1870. the patent was extended for seven
wears longer. The construction of the
Head Blocks for circular saw-mill is of
much more importance than many are apt
to suppose. The saw must run well to
make good lumber; but if, from any cause,
/ it inclines one-sixth or one-eighth of an inch
sideways, it matters not so much as to
have blocks which do not set the logs accu-
rately, for if the boards are set 3-l6 or OF an
inch or more in thickness than others,
nothing will correct the error. The boards
will be sawed as badly as they are set. But
on the other hand, il the saw is so filed or
set that it draws sideways, it does not show
! it so much in the lumber, as it ordinarily in
clines the same way every time: Ihls can pc
corrected in the filing and setting.
To get perfect head block, many difficult
ties are to be overcome, apparent only to
those experienced in building and running
mills, and who have also devoted much atten-
ton to learn the causes OF and the remedy
for imperfect saving. The accuracy OF thick
ness desirable, can never be secured by me-
chanical principles heretofore employed.
Neither the rack and piniOn, screw, in
i cline plane, or anything of the kind,
will give it, A quick motion will give thicker
board than slow one. A light log will be
thrown farther than heavy one. The twist
ing of q connecting shaft, used IN connection
| witt rao
variation; one part of the gearing gets
/ clogged with saw dust, while the other parts
are free, another cause of irregularity. The
screw blocks are slow, laborious things.
There is no self-adjusting principle connected
with them. The handle must be stopped
with precision, or there will be great variations
of thickness Much time is lost in adjusting
the thickness, and anything like accuracy is
out of the question. The cogs in the rack
and pinion blocks soon wear loose, and leave
the knees free to be thrown too far
by quick movements of the lever, or to be
| AIRED and drawn forward under the motion
of the saw with a light cant. Cogs also wear
very irregular-one cog more than another.
The force of logs turned against the knees
often break off the corners of the cogs, caus-
ing great irregularity in the lumber. The
screws in screw blocks, with SO much turn
ing under pressure to move the logs, wear
loose very fast, in two places, viz: The
threads in the nuts on the knees, and between
frames. They soon get very loose, and per-
NIT the Earring of the mill and the drawing OF
the saw to move the cants, as they become
thin and light, 80 as to make the lumber UNI
even in thickness. The browning excellency
claimed for the Stearns Blocks, lies IN the
delicate and nearly absolute mathematical
precision and uniformity in thes adjustment
OF the thickness.
This point or so much Importance is secur-
ed by the use of eccentrics, so applied in CIV
ing lateral motions to the log, as to be reach
ing or passing their centers when completing
the motion, and adjusting the thickness. Its
motion will be fastest when first started and
will continually decrease until it ceases on
reaching dead centre. This gives slow
movement when nearing the required thick
! ing the molten beyond. The advantage over
, all resistance is complete. The heaviest logs
are adjusted with the same precision as the
Highest. The setting arms work In pairs-one
advancing while the other is receding, 80
that the log is set forward by the back,
the handle. This prevents q retrogade
motion of the log. It also doubles the pur-
chase, making the movements light and easy.
This application of the eccentric secures q
most perfect self adjustment OF thickness
without any trouble and delay on the part OF
the sawyer. SO perfect is the eccentric move
ment as to accuracy, that we do not, gain or
lose the thickness of paper in saving up
large log. In the first place, we have the self
adjusting principle, giving such q slab as
will leave board at last neither too thick
nor too thin; and then as we neither gain or
lose as mueh as the thickness Of paper in
cutting up log, the last board ls sure to
come out right every time. Though the
movement of the handle be continued, the
knees cannot be thrown forward nearer
the saw than the thickness of board.
Thus the cants for boards are sawed,
leaving either a perfect board, or an
inch and half or two inch plank, as the
sawyer chooses, without stopping even to
look at the blocks, and the last board as
<quickly as any. The wear OF the eccentrlcs,
or their journals, or the yokes, never causes
the least inaccuracy. The eccentrics have
plenty of surplus rise, and if they should
wear q sixteenth of an inch less, it could
make no variation in the setting-not the
whole log-so perfect is the adjustment
made by an eccentric on reaching dead
center. Tapering lumber may be sawed, as
one block may be thrown out of gear while
the other is moving the difference. The
beauty AM excellence OF this
arrangement cannot be fully un-
derstood without seeing the blocks,
and watching their operation on the
mill. The simplicity, directness and power
of the movement, the evident durability OF
the blocks, and the ease, dispatch and per-
fecJ accuracy in setting the various thick
nesses in the dark pleases all who witness
Them The neat and uniform appearance OF
the lumber, also, which is sawed on the Ec-
centric Blocks and piled about the mills, sei-
dom fails to arrest the attention OF visitors.
Owners of planning mills know well that too
much is wasted in reducing lumber to uni
form thickness. The profits OF lumbermen
| in the United States are lessened annually
many millions OF dollars by unnecessary
waste from the use of imperfect mach merry.
Probably BIG Of an , inch is pansd off fin in
should suffice. This is an unnec-
essary waste of about one-tenth of the lum.
Der. Suppose it worth 500 per one'thousand
| feet, the loss is So per thousand feet in guam
tity from the logs. Then there is, at least,
| 81 per thousand feet in duality; for boards
sawed even will bring, at least, 81 more per
thousand feet than as usually sawed. They
| look better, and are better for every pur
pose. If only for % roof, the shingles will lay
better, and there is saving OF Transports
ton of unnecessary waste. Allowing, thus,
savine.of So per thousand feet, 1t would
amount, per day, to $50, when saving only
10000 feet; $45 when saving $4,000 feet; $50
when saving 10000 feet and many mills saw
more than that daily. A mill saving only
| 100000 feet a year would save 81 800; Saw
| ing 100000 feet would save $4,000; saw
| ing 5000, 900 feet would save SIS, 900 year.
Many lumbermen lose half of the profits of
| the business by poor head blocks, which waste
and spoil the timber Some lose the whole,
and fail of success altogether from this cause
| mainly. ALI may make money in good times,
but those having good mills will make the
most; and in hard times those who waste
| handsome profit by cheap mills, may work
| lust as hard, and make nothing. Lumber can
| be sawed aoeH ON good mill cheaper than 1t
| can be sawed badly on poor one. 1t Is
| thousand times better all around to save the
unnecessary waste, and make perfect ar
| ticle. 1t is better for him who sells the trees
by the thousand, If tenth is saved-he