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SAWMILL EXCHANGE
Sawmill
Comparisons Disclaimer:
This
page has been prepared by myself, Carl Peterson, the inventor of the
original Peterson Portable Swingblade Sawmill. Although I may bring an informed
bias towards these comparisons, I have taken great pains to present the
true and relevent facts as I see and understand them. I have been involved in
the portable milling industry longer than most, and take some pride
that the entire swing-blade revolution emitted from my own backyard.
During the 29 years since I first envisioned the swingblade concept, I
have studied every possible avenue of portable sawmilling. I have used
the felling axe, drowned in my own sweat and sawdust while pit-sawing,
struggled with chainsaw slabbing, tried Pacific bench sawing,
twin-saw operation, and use of bandsaw mills. I have sawed in the
USA, Canada, Fiji, Solomon Islands, Vanuatu, Papua New Guinea, Australia, and
New Zealand, encountering just about every possible type of timber.
Consequently, there is probably no one alive better qualified to advise and
critique the various milling technologies. I believe I have been gracious and
fair in my evaluations. I invite you to share the knowlege I have gained from
all these experiences. With this information, you can easily compare the
strengths of band saw mills, double bladed sawmills ("quarter saws"), circle
mills, and swing-blade sawmills against the requirements of your specific
situation. If you feel I have included any annoying errors of fact, I invite
you to email me at webmaster@truthaboutax.com so it can be made right.
DISCLAIMER:
Neither myself nor my son, Karl Jacob Peterson, haven any financial interests
in Peterson Global Sales Limited, the company now manufacturing and marketing
the current "Peterson Portable Sawmill".
Comparisons-
Circular (Single) Blade Sawmills
This
type of sawmill has been around for ages. They work, and work well, provided
they are set up properly, the blade is properly tensioned and sharpened, and a
skilled sawyer is at the helm. With this concept, the log is usually made to
pass through the permanently fixed-position blade. The downside is that they
take out a considerable kerf as sawdust, usually running at around 3/8". As
well, they usually require an extensive permanent site, and at least some
ancillary equipment such as an edger saw to make them competively productive.
Recovery rates for commercially operated circular saws usually range between
40%-55%, with only the latest state-of-art computerized circular sawmills
achieving anything close to that 55% mark. The more aged circulars on the
market also seem to be famous for cutting boards with a lot of thickness
variations, often plus or minus 3/8". In today's competitive market, it just
doesn't make sense to buy an old circular mill, spend a whole lot of time
setting it up on your site, and expecting to make a lot of money with it. On
the other hand, if used solely for your own requirements, running one of
these "oldies" can be a fun and enjoyable experience, and
reasonable quality timber can be made to fill your own requirements. The Frick
mill is included in this category.
There
are a few modern versions that are mounted upon easily moveable trailers. These
mills can be effective cutting high volumes of small-sized logs.
Unfortunately, they tend to be very expensive, requiring the edger/resaw
equipment to be built in-line with the major breaking-down saw. The Kara
mill is one such example.
Comparisons-
Twin Blade (Double Bladed) Sawmills
The
twin blade concept came into being in the mid 1950s and has been around ever
since. There are a great many different variations using these two blades,
which are set at 90 degree variance to each other. With these mills, the
cutting blades are usually mobile, passing through a stationary log. A single
(or double) board can be cut and removed with each pass down and back upon the
log. This concept allows smaller and more stable blades to be used, usually
allowing the saw kerf to be reduced to between 1/4" and 3/8". These mills tend
to be reasonably heavy, requiring a robust trailering base as a mounting
foundation. Major advantages of this type of mill are the ability to saw
very large logs with moderate horsepower (often between 20-60 hp) and in
automated versions the ability to return the sawn timber or flitches back to
the operator. They are especially practical when cutting 1" thick vertical
boards, whereby the engine horsepower is not tested in making two wide cuts at
the same time. With board drawback device, this type of mill sings cutting
those vertical 1" boards.
Recovery
rates with these mills can usually average between 50%-60%. And because
they make at least two cuts at a time, edgers and resaw equipment are not
required.
The
downside is, these mills struggle when cutting smaller logs. The double blades
have been known to toss small logs that are not well anchored a fair distance,
even causing severe injury on occassion. They also struggle hugely when sawing
timbers with high tension. In such cases, it is almost impossible to saw
accurate dimensions with this type of mill. Because recovery rates are not
competive with swing saws or bandsaws, the twinblade saw should be
considered when sawing logs over 20" in diameter, cutting dimension
timbers that don't exceed in combination around 10" of total cut (unless very
large motors are used), while cutting logs of generally lower value wood. Examples
of twin-saw sawmills include Mighty Mite, Mobile Dimension, Mahoe,
Forestmill, and Rimu.
Comparisons-
Bandsaw Blade Sawmills
There
are scores of bandsaw manufactureres around the world. The bandsaw
has found application in every thing from cutting hobby wood in the home
workshop to breaking down large logs in multi-million dollar timber processing
plants. Bandsaws are at their best in very specific situations. Because
of their extremely small kerf, they are ideal for resawing flitches and
cants into finished boards. For this purpose, they are unsurpassed by any
other practical technology. The market in bandsaws designed for
reducing whole logs has profligerated on the back of a whole lot of hype and
propaganda regarding the extremely narrow saw kerf and the increased
recovery rates theoroetically possible.
Unfortunately,
when designed to cut whole logs in a portable operation, a lot of compromises
need to be made with this technology. Firstly, the bandmills have to be
designed to cut logs up to around 30 inches in diameter. Otherwise they miss
out on a great deal of the portable milling market. And when cutting
those large logs, the technology struggles to provide accurate and straight
cuts. Unless the band blades are immaculately sharp and perfectly
tensioned, those large cuts tend to wander somewhat through the cut. Unless
the logs are debarked before sawing, the bark, sand, dirt, grit, and small
stones lodged therein quickly dull the blade and lead to even more deformed
sawn timbers. And of course, whenever the band blade gets dull,
it wanders all over the place. You throw that wavey board away, put on a
freshly sharpened band, cut another board, and throw that one away, too.
In
most portable sawmilling situations, the bandsaws just do not cut it
for accuracy, recovery, ease of use, or speed of cut. You have to be an expert
sawyer to make it work at all, bandsaws are almost always slow compared
to equally priced swingers, they tend to waste a lot of boards due to
wavey cuts, they have difficulty cutting stressed timbers (again, a lot of
wasted boards), they struggle on large logs, and they require an awful lot of
double handling in resawing slabs or edging boards. And on top of all that,
most serious bandsaw operators spend a couple of hours per sawing day
just resharpening and readying the band blades for the next day's
sawing.
Don't
get me wrong. There is a lot of great technology employed in the more
expensive, automated band sawmills. The point is, it's often the wrong
technology for sawing logs into dimensional timbers. It's therefore overly
expensive, relatively unproductive, labor intensive, and is simply the wrong
application. Now, some of these problems can be minimized by sticking to
smaller logs, debarking the logs (a lot of work), and adding an edger
(expensive) to the operation. But my back is already hurting just talking
about it!
On
the plus side, most portable bandsaws can be used effectively and efficiently
as practical re-saw machines. That is, use them for resawing cants and
flitches into thinner stock boards, rather than trying to reduce large, whole
logs into finished boards.
Examples
of popular portable bandsaws include Woodmizor, Baker, Timberking, Cookes,
Norwood, MSG, Timber Harvester, and Hud-son.
Comparisons-
Swing-Blade Sawmills
The "swingers"
have really taken the portable sawmill market by storm. Time and time
again they have shown at portable sawmill shootouts, through Lucas
and Peterson, to be able to out-gun other mills costing two or three
times as much. In most versions highly portable, they have also been able
to merge great cutting speed, consistent accuracy, with very high recovery
rates; usually surpassing bandsaws in recovery in practical field
situations. The swing blade saw kerf is usually well under 1/4", with
some special applications possible using just over 1/8" kerf. But
the secret here is not in the thin kerf. The real secret lies in the consistent
accuracy and consistent sizing achievable. The relatively smaller swing
blades distort less than larger circular blades, and are more
stable in the cut. And because they have the entire motor horsepower focused
on a single cut in each direction, they effectively cut twice as fast as an
equivalent twin saw system laboring through two cuts simultaneously.
Swing
saw blades are cheap and easy to maintain. They can be sharpened on the
mill in less than a minute or two, sharpened perhaps a hundred times before
being retoothed, and require only a couple of sharpenings per day. Obviously,
a sharp blade will cut faster than a dull one, but at least on a
swinger a dull blade will usually still cut accurate timbers. In the
final analysis, the blade maintenance costs on swingers are only
about 1/10the the cost of bandsaw blade maintenance.
Another
advantage of the swingblade mill is the ability to "double cut"
with the horizontal positioned circular blade. With the Peterson
mill this is easily effected by first sawing on the left side of the log with
the right side of the blade, sliding the carriage to the right, and by
then sawing on the right side of the log with the left side of the blade.
With the Lucas, the carriage is lifted and rotated 180 degrees to
achieve a similar end. Both the Lucas and the Peterson "ATS"
are at their best sawing logs larger than 20" in diameter. The Peterson
"WPF" is equally at home with either small or larger logs, and
also boasts a single rise and fall mechanism.
Lucas
swingblade mill has been around in the USA longer than Peterson.
The Lucas mill began as an early Peterson-type mill with the
addition of two rise and fall winches. It has become a slick outfit, well
marketed and supported by Baily's, and generally well presented when
new. There are probably five times more Lucas mills in America than Petersons.
Second hand Lucas's are far more abundant, and can often be had at a
bargain. A good Lucas mill can achieve awsome production on large logs
equalling the Peterson, and in most configurations is at least slightly
less expensive. On the down side, cheaper materials are used, the machine is
more prone to rusting, Lucas blades are more vulnerable to heating and
distortion, and the Lucas is generally made for earlier consignment to
the scrap heap. From an operator's point of view, there is a lot of walking
required, as the winches are located at oppositie ends of the tracks. When
used by a single operator, double cutting becomes all but impossible,
or at least impractical, as the carriage must be completely turned around. As
well, the tracks become dangerously skewed when dropping down one end at a
time. Lucas has recently begun offering a 10" cut model, but I have not seen
one in operation yet.
Petersons
sawmills boast a lot of precious metal in the construction, being
predominantly stainless steel and aluminum. The Peterson blade
locking mechanism is reportedly easier to use, more operator friendly, and
more reliable than the Lucas gas strut. Double cutting,
difficult with the Lucas, is extremely easy to effect on the Peterson.
Peterson also makes a 10" cut version, an automated version (the "ASM"),
and a small electric version called the "Skillmill" costing
only US $3900.
The Peterson
"ATS" (all terrain sawmill) uses two winches at one end, saving
boot leather and time walking back and forth, and making accurate sizing
easier. The "ATS" does not have the constraining top cross
member that the Lucas has, which limits the log length ability on large
diameter logs.
The Peterson
"WPF" is equally at home cutting large or small logs, being
transported between sites or in fixed site arrangement, and in cutting short
logs or very long logs up to 60 feet long. The "WPF" is Peterson's
most popular commercial-grade mill. Although significantly more expensive than
either the Lucas, or the Peterson "ATS", the "WPF"
mill offers better functionality, more flexibility, easier access for operator
and log, and improved accuracy. An electric rise and fall option adds to
operator convenience.
"TURB-O-SAW"-New
kid on the block.
Carl
and Jake Peterson have finally released details of their new 12" cut
automatic swingblade mill, which has been named the "Turb-O-Saw",
or "Turbosawmill". This new prototype mill features the
patent-pending "turb-o-blade" which incorporates a series of holes in the
blade to reduce gyroscopic forces during blade changeover, reduce friction
resistance, facilitate blade cooling, allow self-tensioning, and generally
provide faster and more efficient sawing. This bundle of benefits allows
thinner blade steel to be used and thinner tip widths, providing even more
efficiency, faster cutting, and greater size of cut. This blade technology
combines with a new patent-pending frame design to allow simple but robust
construction, easy operator and log access around the mill, unsurpassed
stability in the cut, rapid setup, and quick readiness for transport to a new
site.
Carl and Jake are planning to unveil
their latest improvement, being the new "counter-cut"
facility, soon. This involves a smaller 6" cut blade permanently mounted in
the vertical position, but able to be raised above and away from the cut,
lowered partly down into the vertical cut plane, or lowered all the way to
intersect with the horizontal cut plane. This allows the mill to be used as a
standard 12" cut "swinger", a "quarter-saw"
type with 12" horizontal cut and 6" vertical cut, a "counter-cut"
mill able to saw vertically in either direction so as to release and
retrieve three sawn boards at one time, or an "equalizing swinger"
whereby the cutting load can be evenly distributed between both vertical and
horizontal cuts. The
mill will be publicly demonstrated in public at the New Zealand National
Fieldays, Mystery Creek, Hamilton in mid June. Needless to say, this will be a
real show stopper.
For
more details, go to www.turb-o-saw.com
, or www.turbosawmill.com
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