The Evolution of Modern Band Saw Mills for Sawing LogsPrescott, D. Clint
Philosophy
The Evolution of Modern Band Saw Mills for Sawing Logs
Prescott, D. Clint
Sawmills
[Illustration: PACIFIC COAST, 10 FOOT BAND MILL]
In every respect these mills are splendid creations and exhibit a vast
stride in advance of the earlier mills described herein.
All of these mills are provided with a surrounding base, a powered
upper guide, quick opening lower guide (as shown on page 45), live
roller, means for maintaining alignments and adjusting the upper wheel
when changing saws, the latter being done either by hand or power as
required; and the upper wheel in all of these mills when raised to the
maximum point admit of the use of a long saw for sawing occasional
large logs, a saw two feet shorter being in use normally for medium
sizes of logs which are mostly cut. And these mills in combination with
a Prescott carriage constitute an equipment absolutely unrivaled by any
other productions in the world.
Rack and pinion head blocks, every piece of which is an open hearth
steel casting, are furnished in sizes varying from 36 inches to 72
inches, being the distance the knees recede from the saw line; and
these with frames proportionate in dimensions and composed of well
seasoned southern pine timber, well ironed and braced, comprise great
strength and durability.
For mechanically exact setting, all racks, pinions, taper sets and
ratchet wheels are cut from solid blanks in a gear cutter. The knees
are operated either by hand lever and quadrant, the familiar way, or by
a Prescott Steam Setting Machine, which advances them for 4-inch lumber
or any thickness less, varying by 1-64th of an inch to every click of
a pawl on the ratchet wheel, and that too with a single rearward and
return stroke of the piston, so that great speed and accuracy are the
characteristics of this machine; and with it an increase of cut is
obtained by reason of the fact that the setter does not get tired, and
no sawyer will have to wait for him. And more, with them a mill man can
keep a good setter who otherwise might be on the hunt for an easier job.
These carriages are also supplied with Friction, Spring or Steam
Receders, which latter can be employed in all cases where Steam Sets
are used for which steam is delivered to the moving carriage. The value
of steam receders consists in the ability to advance or recede the
knees at any time whether the carriage is moving or at rest, and for
receding the knees of large blocks sawing short logs only.
[Illustration: Standard 3-Block Carriage with 4-inch combined steam and
ratchet set works]
A Revolving or Flat Scale always indicates the position of the knees.
Dogs hold the logs. An Automatic Offset gives a clearance of the saw
when on the gigg, and Steel Trucks and Steel Track necessarily go with
such a carriage, composed either of heavy T Rail, or the lighter rolled
track, according to the size and weight of the carriage.
For accuracy and speed these carriages have no equal, especially when
handled by a Prescott Direct-acting Steam Feed.
[Illustration: PACIFIC COAST SCREW BLOCKS]
Public-domain text, read in full here on John Shaqi.
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