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When it comes to creating dados,
grooves or rabbets/rebates (whichever you wish to call them) there really is no
quicker way than to cut them on a table saw using a specialized dado
cutting blade set, particularly if you need to cut more than one. While
you can also cut them with a router, the table saw and dado set can slice
them much more easily and can cut deep dados or grooves in one pass with
no issues of material burning or rapidly dulling router bit edges due to
excessive heat.
Many saw blade manufacturers offer
dado blade sets, the best being offered for many hundreds of dollars for a
set. Sometimes as much as $400-$500 a set. For the budget-conscious
woodworker, finding a quality set under $200 can be a challenge. The
Northwood Dado set does come in under the AUD$200 price range, but can it
produce high quality, flat bottomed cuts in a wide range of material?
Let's find out.
The Northwood Dado Set
The Northwood set is an 8" stacked dado set featuring two outer
cutting blades, and five inner chipping blades. The set ships in a very
nice, heavy duty aluminum case with inner foam padding. This is perhaps
the best Dado set case I have seen from any manufacturer so far. It
protects the blades and tooth edges very well in transit or storage. A
thumbs up there.
Inside you find the blades, and the
teeth of each blade are protected by clear plastic tubing. This ensures,
at least in this case anyway, that the blade teeth were damage-free out of
the case and ready for use. Also included is a packaged set of round brass
shims that are used between the blades to fine-tune the thickness of the
set when installed on the table saw arbor, and hence the thickness
of the cut.
The set has a 5/8" arbor hole, so they
can only be used on table saws having a 5/8" arbor, and on an arbor that
is sufficiently long enough to accept the dado set as well as the arbor
nut to secure everything in place. Some table saws are not designed to use
dado sets, and hence only have short arbors. The table saw I use, which is
a TSC-10HB Taiwanese-made saw will accept up to a 3/4" wide dado set, but
only just! The Northwood set will allow you to cut dados or rebates from
1/4" wide, through to 3/4" wide, and using a combination of chipper blades
and shims between the two outside cutting blades, you can set virtually
any width of cut in between 1/4" and 3/4" as well. It is like owning many
different width straight cutting router bits, but at a fraction of the
cost.
The blade bodies are all manufactured
from heat treated steel alloy. They do not have special anti-rust
treatments like some other higher-priced sets do, but for the lower price,
there has to be compromise somewhere. Thankfully the carbide quality on
the teeth is one area where no real sacrifice has been made. The teeth
feature fine C-4 micrograin carbide, which will stay sharper longer and be
more durable as opposed to more coarse grain carbide used on low-quality
saw blades. The outer cutting blades feature teeth with a bevel grind
facing in toward the kerf of the set, while the chippers have the
characteristic, and necessary, flat top bevel grind, which allows the
stacked set to cut flat bottomed dados and rebates.
Speaking of the outer blades, each
blade offers 42 cutting teeth in a set combination that resembles what a
good quality combination saw blade might offer. The teeth are arranged in
6 groups of 7 teeth, with extra clearance between each set, presumably to
allow better removal of debris from the cut, particularly when cutting
rebates or dados with the grain of the wood. The combo-style configuration
makes these outer blades very effective cutting in pretty much any grain
direction.
The chipper blades, which are always
positioned between the two outer cutting blades, work almost like a chisel
to punch, or chip out the middle material of the dado or rebate. The set
includes four 1/8" chipper blades, and one thinner 1/16" blade. Using a
combination of number of blades and sizes allows the wide range of cut
widths to be achieved as mentioned above.
Setting Up A Dado Set
Setting numerous blades up on your saw arbor correctly is important to
ensure a good quality cut and eliminate any chance of damaging the blades.
When set on an arbor, the cutting teeth actually overlap each other
slightly from one blade to the next, so the cut is properly and completely
made. As a result you need to offset the location of each blade's teeth in
relation to the blade(s) next to it. No teeth from different blades should
be parallel to each other, because this would damage the teeth and you
would likely find the blade bodies (being slightly thinner that the tooth
width) would not be sitting firm against each other. For safety and
accuracy, the blade bodies need to be snug to one another on the arbor,
and properly secured with the blade arbor nut so they cannot move or
rotate on the arbor when the saw is spun up. So, as long as you make sure
all blade bodies are snug to one another, and that no teeth from the
various blades are touching each other, you should be good to go.
If you need to slightly alter the
width of a dado, use the round brass shims supplied. These slide on the
arbor in between blades to widen the whole set by the desired shim
thickness amount. The best way to measure the overall set thickness is to
measure the distance between the outside edges of the cutting blades teeth
with a digital thickness gauge. Or, perhaps better yet, find some scrap
and make a test cut for fit or sizing first before running your project
material through.
The Northwood Dado Set in Action
The sign of a good dado set is in its ability to create accurate,
flat-bottomed dados with minimal vibration in use. I tested the set on a
wide range of materials, from softwoods to hardwoods and composite
materials (MDF, plywood and chipboard etc).
I set the blades up to make varying
cuts from 1/4" through to 3/4" and at varying depths. Bear in mind that an
8" dado set can cut deeper than a smaller 6" dado set because of its blade
diameter. Usually though, in most projects, you will rarely find yourself
cutting any deeper than 3/4 of an inch, but if you do need to make a
deeper cut, it is good to know you have the extra blade capacity there to
do so.
To ensure the most accurate cuts and
to test the flatness of each cut, I used featherboards and hold-downs on
the workpiece to ensure the material was kept tight to the table and guide
fence. I know the arbor on my particular saw runs very true indeed so
there would be little effect of arbor runout on blade cut quality in this
instance.
To begin with, when setting up the
blades, I found the blade bodies were flat and fit together on the arbor
quite snugly. This is a good start. The
fit of the blade on the arbor can also affect the smoothness of the bottom
of the dado. The Northwood set was slightly loose on my arbor, in
comparison to one of my other dado sets. This made it much easier to add
and remove blades, however, the bottom of the cut, as you might see below,
was not perfectly flat, but for all intensive purposes, I still consider
it a good cut. Upon starting the saw up I looked for
excessive vibration, both visually and audibly. Both checked out ok. No
real sign of blade wobble when the saw slowed to a stop (this is usually
where you can notice it the easiest) and I didn't notice any excess
vibration over and above what I usually expect from my table saw (which is
very little to begin with).
During the cuts I made a note to check
for excess noise coming from the blade. Usually, high quality, sharp
blades will exhibit very little excess noise under load, whereas poorer
quality blades can generate a lot more noise, usually because the blade
may not be running true and cutting more material as it moves from side-to-side every so slightly. The Northwood set appears to run very true on my
saw and with no more noise (as far as my ear can tell) than my best dado
set I have used for many years. I was quite surprised in fact, given the
lower cost of the set. I would normally have expected to find something
noticeable in this area, but subjectively, there was not any discernable
difference.
Bunny ears are hardly noticeable unless you look very
closely.
What about bunny ears? What bunny
ears? You know, those little triangular "notches" that are created on the
outside edges of dados caused by the beveled grind of the outer blades,
and often slightly deeper than the flat bottom middle of the cut. Some
call them rabbit ears, and I have even heard them called Batman ears.
These are very common with many dado sets. Even my better sets exhibit the
slightest hint of rabbit ears. The Northwood set is not totally immune to
this side effect. However, like my better sets, the bunny ears are very
small, and not really noticeable unless you are looking for them. There
are less noticeable ears than with one of my sets that cost twice as much.
Here you may notice the lines in the bottom of the cut,
indicating perhaps the chipper
blades are not all the exact same diameter, or perhaps it is the slightly
loose fit of the
blades on my saw's arbor? It is difficult to tell which. Nonetheless the
error appears more noticeable in this photo than it does in actual
application and fit.
The Northwood set creates flawless and sharp edges on
melamine panels and all woods.
Overall Results
Results were the same across all types of cuts and materials. Apart
from the slight deviations in the bottom of the cuts, the edges were all
very cleanly cut and with minimal chipout on the backsides as the blades
left the material. I did find making a dado along the grain, particularly
in softwoods, produced a smoother cut than with crosscuts. Perhaps as to
be expected, but worth noting nonetheless.
The set is very well
balanced and it slices nicely during the cut. Not a lot of pressure is
needed to move the material through the blades, indicating sharp cutting
teeth and efficient debris removal by the chippers. rarely did we
encounter any burning of material either.
The Northwood Dado set
retails for AUD$149.99, which, at present, is less than half the price of
a popular named brand set in Australia. I wont claim this set is as good
as perhaps the Infinity Dadonator, but the Dadonator is priced at close to
twice as much.
For the budget minded,
the Northwood set is a good start into the world of dado blades, and if
the fit of the blades happen to be slightly tighter on your arbor, its
very possible you could achieve very flat bottomed dados or rebates with
this set. It is certainly far easier and much faster to cut dados on the
table saw than it is with a router, and with only one dado set, you can do
the work of many sized router bits. The dado set is certainly the most
economical way to cut dados, grooves and rebates, and the Northwood set
makes it affordable to just about anyone who needs to perform these
cutting tasks.
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Northwood Dado Set Photos
All photos copyright onlinetoolreviews.com. Use without prior
written permission prohibited
Handy storage case makes transportation easy and, more
importantly, protects blades during storage.
Chippers in one end, outer blades in the other.
One of the outer blades with 42 teeth in groups of 7.
The tooth arrangement helps clear debris more effectively.
Full body chippers with 6 cutting teeth each. Here are the 1/8" and
1/16" chippers.
Brass shims allow fine and micro adjustment of cut width. These are
placed between blades as required.
The Northwood dado set installed in my tablesaw. Here it is set up for
a 5/8" width cut.
This is why its called a stacked dado set! Notice the chippers are
offset to each other.
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