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When it comes to plunge cutting with the router,
or even routing dadoes or mortises the straight flute cutting
bit was the tool to use for the job. That was before the spiral
router bit hit the market. Now we had a router bit that looked
like a drill bit, and promised much faster plunge and slot
cutting action with a cleaner edge finish too.
I admit that most of my dado work up to now has
been done on the table saw with a dedicated dado set, and any
mortises I needed were cut with my dedicated mortise machine,
but of late I have started utilizing the router more for joinery
work, as opposed to edge shaping, which is what I had
predominantly used it for up until now. And as such, I needed a
better way to cut mortises and stopped dadoes, so I decided to
grab some spiral bits. Now, there are many brands on the market,
but I headed straight for the top it seems and picked up a few
Freud Spiral router bits based on feedback from other owners of
these bits. I have a few other Freud bits already and they have
proven to be quality router bits.
Freud Spiral Bits
When it comes to spiral bits, there is essentially one thing
you need to know, apart from getting the right shank size for
your router and the desired length and diameter of the actual
cutting edges, and this is whether to buy a spiral "upcut" bit,
or a spiral "downcut" bit. What's the difference? Well, the
difference is in the efficiency that the dust and debris is
moved by the bit. With spiral upcut bits, the debris is moved up
toward the shank of the router bit more efficiently, making them
suitable for deeper mortise or plunge cuts. These bits are best
used for deeper plunge cuts, or if you are using the router to
effectively "drill" holes rather than slots because they can
remove debris from the bottom of the hole/slot where it may have
no where else to go. One of the side effects of this bit design
(because the spiral cutting edges are rotating and cutting up
toward the bit shank) is the possibility of fraying or furring
(perhaps even chipping) of the top edge of the slot or mortise,
particularly if the router bit is of poor quality or becoming
dull. However, if the top edge of the cut is going to be covered
anyway, as in the case of the shoulder of a tenon covering the
mortise edges, it may not be anything to be concerned about.
The up-cut bit seems more widely used than the
down-cut bit however. The downcut bit is less efficient at
clearing debris from the bottom of a plunge cut, however, it
produces a smoother top edge with less chance of chipping,
splintering or furring because the cutting edges and essentially
rotation down toward the bottom of the cut, and the edges of the
slot are supported by the material itself. I have found that
even downcut spiral bits are more efficient at debris removal
than standard straight-flute router bits for the cutting tasks.
So before purchasing, consider which bit you need. Both bits
will work great for cutting shallow slots or dadoes, but the
upcut is more suited for deeper dadoes (these should be cut in
multiple shallow passes however anyway) and the downcut will
generally give cleaner topside edges.
Spiral Upcuts
I am looking at two spiral upcut bits from Freud (My only
downcut bit has finally dulled to an unusable state). these bits
are the 75-102 1/4" shank, 1/4" diameter up cutting bit and the
75-108 1/2" shank, 1/2" diameter up cutting bit. Both are made
in the same way, with the same design and material. The only
difference is shank size and diameter.
Both Freud bits appear to be made with high
precision, and are finished well. Usually you can look at a bit
and tell a good deal about its quality of manufacture just by
its finish. A close examination of the cutting flutes showed
sharp edges and no blemishes on either bit. The bits were a nice
snug fit in both my routers (1/4" router and 1/2" router) and
tightened up readily and easily.
Unlike regular router bits with carbide cutting
tips, the Freud spiral bits are solid carbide from top to
bottom. And not just any regular carbide either. These bits are
made with a special Micro-grain carbide incorporating Titanium
and Cobalt. Freud calls this TiCo High-Density carbide. I don't
have any way of examining this carbide under a high powered
microscope so I have to take their word on it. I am sure it is
all above par and the performance of the bits would seem to
suggest this is some pretty durable material in use. The bits
are made in Italy.
The Bits in Use
I ran the bits through various tests in softwoods, hardwoods
and sheet materials. Nothing terribly scientific. I simply cut
some mortises in face grain and end grain in all materials, and
then some direct plunge action cuts (drilling) using the bits.
Varying depths of cuts and mortises across the grain and with
the grain etc.
The first thing you notice with using a spiral
bit is the ease with which it plunges down into material to make
the initial plunge cut. With regular straight flute bits, this
process if often less than smooth as debris can be trapped
around the cutting area of the bit making plunging difficult and
slow. The spiral bits clear the debris far more effectively and
allow a smooth plunge action to be attained without hesitation
or lifting the bit to clear the hole of any debris remaining
under the bit. As you make a mortise trench, the value of the
spiral bits also becomes apparent. If you have ever cut mortises
or slots with standard straight flute bits, you might find you
get to the end, then lift the router and see all the dust still
jammed in the slot. With a spiral bit there can be debris still
in the slot, there is no doubt about that, but the amount is
much less and rarely will the slot ever be crammed full and
packed tight with dust. This is perhaps even more
noticeable when routing a mortise with the bit set in a
router in a router table since the table can close off any exit
pathway for debris to take. A spiral bit will draw this debris
downward to the router and hopefully be ejected from the mortise
and from around the router with an extraction system of some
kind. Needless to say, if your router has a good extraction
system, you will end up with a cleaner mortise/dado/slot cut
once all is said and done. In many cases with these spiral bits,
there is little or no sign of dust in the mortise at all if you
have a strong extraction system in place with your router. This
makes cleanup almost a non-issue.
Also, consider heat on the bit. Excess debris
around a router bit can create more heat, and the hotter the
bit, the higher the potential for it to dull much quicker. I've
"burnt" more than a couple el-cheapo straight cut bits routing
dadoes and mortises in the past. Cheap router bits are not a
wise investment, unless they are for a one-off task where
quality of cut is not terribly important. Quality router bits
are worth their weight in gold... well, carbide, anyway. Since
spiral bits more effectively remove dust and debris, there is
less chance for this heat buildup to occur.
I made many cuts in different types of materials
and in both soft and hardwoods. The results were virtually the
same across the board. Smooth edge, clean mortise and
trench/dado cuts in virtually all materials. The only time I had
furring of the edge was when cutting across the grain on pine,
which has a tendency to fur up easily anyway. This was readily
removed with sandpaper. The bottom of the cuts were all very
smooth and more than suitable for visible shelve joints or
similar joinery.
Overall I am very happy with the Freud Spiral
Upcut bits. And although straight flute bits are quite a bit
cheaper on initial purchase, I believe spiral bits offer more
value for money over the life of the bit, and give better
results to boot.
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As Reviewed Above
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Other Common Freud Spiral
Upcut bits
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Rockler.com (USA) |
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Freud Up-Spiral Router Bits
Upward spiral is perfect for ejecting
chips from mortises. It’s also the ideal bit for pattern
routing because the best face goes down while cutting, with
templates attached to the top. 1/2" shank...
Freud Up-Spiral Router Bits
Rockler.com |
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Freud Spiral Router Bit Photos
All photos copyright onlinetoolreviews.com. Use without prior
written permission prohibited
Freud 1/2" and 1/4" Spiral Upcut Bits
Each bit has two spiral cutting flutes
Each bit is precision machined and finely finished.
Two plunge mortise cuts in melamine. The edges are clean and sharp,
even where the bit was plunged down into the material.
This mortise cut across the grain of some pine did produce some furring
around the top edges using the upcut bit. But this is easily removed with
sandpaper and you can see the top edges are still sharp and clean.
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