To the Editor:
I feel it is important to bring to your attention potentially
misleading information in the
article on wormdrive and hypoid gear construction saws by
Tim Uhler (2/04). As referenced in the author's lead paragraph,
users frequently and incorrectly refer to various inline
circular saw models as wormdrive saws. While this error is
recognized, the article perpetuates the incorrect use by
categorizing the entire test as "wormdrive saws" on the cover
and in the story title, when half of the tools tested are
actually hypoid gear circular saws.
Distinguishing between wormdrive and hypoid gear saws as part
of the larger category of "inline circular saws" is important
to any user making a tool purchase. By referring to
non-wormdrive saws incorrectly, the article could mislead the
average user to purchase these saws and think they offer the
For more than 75 years, our wormdrives have been the industry
standard in accuracy, durability, and power in construction
saws. While other inline saws have benefited from being
associated with wormdrives, they should not be tested or
compared as such, because they don't offer the same benefits
wormdrive users know and appreciate.
Finally, users should also recognize that the terms
"wormdrive" and "inline" are not interchangeable; rather, the
first is a subcategory of the second. Because a saw is inline,
meaning the motor and gear train fall in line with the blade,
does not mean it has wormdrive gears. By perpetuating this
common misunderstanding, the article only does readers a
disservice instead of helping them to make more educated tool
Director, Product Development
Bosch Power Tools
Mt. Prospect, Ill.
Load-Tested Deck Ledger
To the Editor:
Thank you for the practical article
Ledger Connections" (3/04). The article raises a question,
though. It appears that in these tests the joist hangers are
attached to the ledger only. Was any consideration given to the
effect of the joist hanger nails on strength or deflection,
assuming these nails penetrate through most of the thickness of
the band joist? It seems that this would add a significant
additional factor of safety.
Mark J. Reinmiller, P.E.
Coauthor Frank Woeste responds: Hanger nails are typically
1.5 inches long and have a larger diameter than normal. Look
for an N10 in the Simpson catalog. If you use a
smaller-diameter nail, you have to reduce the hanger rating per
the manufacturer's literature.
I understand the point you are getting at, assuming the nails
were longer, but any increase in the safety factor would be
uncertain, especially since you are mixing fasteners (bolts
with nails). The NDS does not permit mixing, even though it is
common in some applications.
To the Editor:
I just wanted to pass along a note of thanks for the continued
publishing of your magazine. This month (2/04), in addition to
reading an article by an old classmate
for Coastal Homes”), I was pleasantly surprised to
see a woman on the cover. Your magazine does more than just
educate. It brings us together in many ways. Keep up the great
Carolyn Coleman Burke
Hawtin Jorgensen Architects
To the Editor:
I am a subscriber and regular reader of your excellent
magazine. I may be wrong, but I suspect that your February 2004
cover is the first featuring a woman wearing the tools. In an
industry known for the display of pictures of women wearing as
little as possible, I find your low-key inclusion wonderfully
Women also appeared on our covers in February 2002, June
1999, and January 1985 (shown), when we were New England
— The Editor
To the Editor:
As a custom sales rep for the leading materials supplier in
Key West, I deal with hurricane-rated products on a daily basis
and would like to pass on some observations to code writers,
code enforcers, and manufacturers of tie-downs. A mistake that
I see almost daily is carpenters putting joist hanger nails in
every available hole of every strap, tie, or anchor. As a
consequence, the 2-by framing members are shredded,
compromising the capacity of the metal connector. This issue
needs to be addressed before the next big blow from the
Manley DeBoer Lumber
Key West, Fla.
Proctor Test Explained
To the Editor:
The answer to the question regarding the compaction of gravel
suggests that a "Proctor test" be performed. However, this is
only part of the answer; a Proctor test alone will not
determine the compaction of the in-place gravel (or
The Proctor test determines the theoretical maximum dry
density for the gravel (or soil) being compacted. This test is
normally performed in a laboratory (but can be performed in the
field) on a sample of the gravel or soil. The standard Proctor
test (ASTM D 698) is probably the most common, while the
modified Proctor (ASTM D 1557) is also frequently used. Both
tests determine the density of the soil over a range of
moisture contents using a standard amount of compaction energy.
Using the results of a series of tests (at different moisture
contents), the theoretical maximum dry density is
The next step in determining the in-place compaction of the
gravel (or soil) is to perform an in-place field density test.
This was not mentioned in the answer to the question about
compaction. Several test methods are available to determine
in-place density, using different equipment. The nuclear gauge
method is probably the quickest (and may be the most common),
but others, such as the sand cone method, are used.
Once the in-place density is determined, it is compared to the
theoretical maximum dry density from the Proctor test. The
result (the compaction) is usually expressed as a percentage of
the Proctor value. The proper compaction percentage depends on
the actual use of the gravel or soil material. Structural fill
under a foundation generally requires a higher percentage of
compaction than backfill against a foundation wall. For gravel
used as a base for driveways or basement slabs, 95% compaction
(based on the standard Proctor, ASTM D 698) should normally
provide very good results.
Joseph D. Shuffleton, P.E.
Engineering and Technical Consultants
Blames Unskilled Labor
To the Editor:
Hats off to the New Jersey State Commission of Investigation
and the Orlando Sentinel for exposing the quality, or rather
the lack thereof, in many homes being built today
(In the News,
2/04). Not only are the tradespeople who build these McMansions
"unsupervised" and "unskilled," but they are often poorly paid.
It is no coincidence that more and more of these workers are
coming from Mexico, Central America, and eastern Europe.
Contractors have found a gold mine of cheap labor: workers who
may work very hard but do not understand local codes or best
practices and very often cannot thoroughly read drawings or
specifications. Combined with time pressure applied by their
employers, this is not a recipe for high-quality work....
Septic Design Clarification
To the Editor:
After reading the article
"On-Site Septic for
Problem Soils" (3/04), I want to clear up some misleading
statements. I am a Vermont-Registered Professional Engineer and
also certified as a Licensed Designer for septic systems. I
operate a general contracting business that performs septic
installations of all types.
The author states that the usual solution for dealing with
poor soils and small lots is a pressurized septic system
instead of a gravity one. He also states that "there are
technologies that make it possible to install a conventional
gravity-supplied system on many lots where pipe and stone are
unsuitable." Both statements are incorrect.
We design septic systems to perform their job for a long time.
To do this, we must assess the assimilative capacity of the
site and evaluate the limiting factors for operation of the
system, such as shallow depth to the seasonal high groundwater
table, shallow depth to bedrock or impermeable soils, small lot
size, and excessive slope. When these factors are present, we
must design a system to accommodate the limitations within the
requirements of the current state rules.
We are required to install the leach field portion of the
system with adequate vertical separation between both the
seasonal high groundwater table and bedrock (or impermeable
soils). If either is present at too shallow a depth, the system
must be raised to maintain the required vertical separation.
Standard in-ground construction techniques can be used if
conditions allow. The next step up is to place the disposal
field "at grade" or right on top of the ground. The last step
up is to place the disposal field in a sand "mound." Each
option provides additional vertical distance for separation
from these limiting factors. The leaching chambers described in
the article can only function in place of a standard in-ground
system. They do not provide any additional benefit to sites
with shallow depth to groundwater or ledge.
Pressure dosing is required for
at-grade systems and mounds. It can be accomplished either by
pumps or by siphon chambers if adequate elevation head is
available. Pressure dosing may also be required if an in-ground
system cannot be sited in a location that is lower than the
septic tank. It is generally accepted that pressure dosing is
superior to gravity distribution. Pressure dosing evenly
distributes septic tank effluent throughout the disposal field
in "doses." This ensures that the entire field is used, not
just a portion. The doses are designed to let the field "rest"
in between. If a plumbing fixture is leaking, a gravity field
will receive a constant drip-drip-drip of water, and the inlet
end of the field can become overwhelmed. With a dosed system,
the field is evenly dosed and still has a chance to rest in
between. I agree that pumps add a degree of complexity and
potential failure to a system; however, the ability to evenly
dose the entire field in a controlled manner outweighs the
costs in many instances.
I believe that the statements made about the general mode of
operation of the Infiltrator chamber to also be inaccurate. The
leach field chamber, similar to the stone in a conventional
trench, only provides a holding area for the effluent. Actual
treatment occurs in the unsaturated native soils beneath the
field. Once the effluent leaves the chamber or stone, the soil
particles provide treatment. The "biomat" described in the
article is of limited value. Also, sufficient oxygen is
supplied to the bacteria that perform the treatment through the
pore spaces in the soil.
A couple of other comments about the system installation as
shown in the article: First, I always specify (and the current
rules require) that flow equalizers be installed in each outlet
of the distribution box to ensure that flow is evenly
distributed to each trench line.
Second, I never allow the inclusion of 90-degree bends in any
septic lines. All bends must be 45 degrees or less.
Third, we are typically required to have both the septic
system designer and the town health officer inspect the system
prior to any backfilling. This must always be coordinated
during construction. Currently, in Vermont, if you fail to have
your wastewater disposal system inspected and certified in
writing by the designer during construction, you are left with
a defective title on your property.
Finally, I always require that final site grading divert all
surface water away from the new disposal field.
I was also intrigued by the Infiltrator leaching chambers when
I first learned about them some years ago. However, despite
their claimed advantages, they cannot take the place of an
at-grade or mound system on a site that requires it.
Thank you for your time. I greatly enjoy reading my copy of
JLC cover to cover each month. Keep up the great work!
Peter W. Giancola, P.E.
Giancola Construction Corp.