Forrest Thin Kerf Woodworker II 10" Saw Blade

Exceptional cuts for a thin kerf blade

forrest_WWII_lead

Forrest Thin Kerf Woodworker II 10" Saw Blade



Forrest is one of the more highly regarded blade manufacturers. I reviewed their Chopmaster blade in 2010, and was blown away by the mirror smooth cuts that I was able to get in hardwood. It virtually eliminated the need for any sanding.
 
Recently, Forrest sent me a thin kerf version of their workhorse combination blade, the Woodworker II. The standard WWII has 1/8" thick teeth, while the new thin kerf WWII has 3/32" teeth. The result is that a thin kerf blade will give you a 25% narrower kerf than a standard blade. These thinner blades require less cutting power, so are better suited for table saws with motors under 3 HP - typically portable and hybrid table saws. Some woodworkers like to use thin kerf blades when cutting expensive exotic woods like ebony and rosewood, as the
kerf
thinner blade will produce about 25% less waste - certainly something to consider when you're milling a quantity of wood in the $25+ board foot price range.
 
Forrest Thin Kerf Woodworker II (TK-WWII) blades are available in either a 30-tooth (#WW10307100) or 40-tooth (#WW10406100) format for just about every 5/8" arbor saw on the market (6", 7-1/4", 8," 8-1/2", 9" and 10" diameters). Forrest recommends the 30-tooth blade if you're primarily cutting 2" to 3" stock, and the 40-tooth blade for stock up to 2" thick.
 
For the past month I've been using a 40-tooth TK-WWII for all my cutting - in plywood, softwood and hardwood. Forrest recommends using a blade stiffener with its blades; ostensibly these dampen vibration (providing a slightly smoother cut) and reduce noise. I mounted the TK-WWII on a stationary Unisaw and didn't use stiffeners. However, lighter saws, particularly portable saws, are more susceptible to vibration, and might well benefit from using stiffeners.


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ATB teeth with a 15° top clearance angle and 20° face hook 
    
The TK-WWII has 40 C-4 micrograin carbide teeth set in an Alternate Top Bevel (ATB) pattern. The teeth have a 15° top clearance angle - these knife-like edges give very smooth cuts the entire width of the kerf. A high 20° face hook angle provides a lot of pull on stock, making for a fairly aggressive cut and a fast feed rate. One of the issues with ATB blades is that they do produce a V-groove on the base of the kerf.
 
C4 carbide is the most durable material for blade teeth and Forrest uses double hard carbide, which give superior blade life. Micrograin carbide consists of very fine grains of carbide powder with titanium added to the binder. This makes for a tooth that can hold an edge longer between sharpening. According to Forrest you can expect up to 300% longer life between sharpenings than you will get from other blades. I suppose that you have to take the company at it's word on this, though just about every review I have read on Forrest blades support the contention of a long service life between sharpenings. It's important to remember than when you get these blades re-sharpened you want to ensure that the original tooth geometry designed for the blade is maintained. If you're local resharpening service can't guarantee this you can always use Forrest's resharpening service, which is quite reasonable, at $21 plus shipping for a 40-tooth blade.


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Laser cut, hand-tensioned and straightened plate
   
The plate from which the saw blade is made is laser cut (rather than hydraulically stamped or die cut), and then hand-tensioned and straightened. This results in a blade that has virtually no runout (+/- .001").
 
There are five slots cut into the outside edge of the blade - they reduce vibration and noise, and help dissipate heat. If you do notice vibration with this blade it's likely to be due to runout on your table saw shaft or the flange that the blade rests against. For information on checking and fixing runout consult Jim Toplin's book "Table Saw Magic", or Matthias Wandel's ezine article.
 
The 5/8" bore hole is precisely drilled as it fits very snugly on the arbor, without any slop whatsoever.
 

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The business end of any saw blade are its teeth. Tooth geometry, quality of the carbide used, thickness of the carbide and the quality of the brazing that attaches the teeth to the plate are all critical components.
 
On the TK-WWII the teeth are manually brazed onto the plate. I found the tooth brazing to be very cleanly done with no gaps or porosity. The teeth are 23/64" long - about 15/64" of this length can be resharpened. The teeth have precise, finely ground and polished surfaces, which should enable you to resharpen the blade at least eight or more times.
 

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Ultra smooth cuts in hardwood (3/4 oak: top; 2" maple: bottom)

What matters, of course, is how a blade performs, and over the four weeks or so that I've been using this blade it has performed flawlessly, whether ripping or crosscutting plywood, MDF, or hardwood.
 
I've kept to Forrest's recommendation and for cuts in sheet stock I raise the blade about 1/4" above the stock, while for hardwood I raise the blade about 1" above the stock. I also installed a zero clearance insert.
 
When I first turned the saw on after installing the blade I immediately noticed how much quieter the saw was. And when cutting stock the TK-WWII continued to run noticeably quieter.


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Crisp, clean rip cuts

I found that the blade cut very aggressively in both crosscut and rip mode, with minimal resistance, through 4/4 or 8/4 stock. Most importantly, the quality of the cut is excellent. Cut surfaces were consistently super smooth. For kitchen cabinetry and trim work you really don't need to do any sanding or plane work. For high-end furniture work you'd still likely want to make a final finishing pass with a hand plane.


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Crisp, clean edges on plywood

On commercial plywood and shop made ply the cuts were free of tearout on both the top and bottom faces (Note: a zero clearance insert really helps by providing close, rigid support as the blade exits the bottom of the plywood).
 
If you install a thin kerf blade you may want to realign your miter gauge, particularly if you like to have the miter gauge aligned as close as possible to the blade. If your saw uses a riving knife it likely is designed to work with a standard width blade. Check with your manufacturer to see whether you should use an alternate riving knife with a thin kerf blade. Riving knives are generally slightly thinner than the width of the kerf produced by the blade. Therefore, the kerf produced by a thin kerf blade might not be wide enough for your standard riving knife.
 
If you own an underpowered table saw (under 3HP motor), or you mill a lot of expensive exotic hardwood, and want to get the best cuts possible from your table saw and the maximum value from your saw blade investment, then the Forrest Thin Kerf Woodworker II is, in my view, a sound investment.


KEY FEATURES:

  • 40 teeth in an ATB pattern
  • Double hard, corrosion resistant C4 micrograin carbide teeth hardened to Rc40-42
  • 5 anti-vibration slots
  • 15° top clearance angle, 20° face hook
  • Run out of +/- .001"
  • Laser cut, hand-tensioned and straightened plate

MANUFACTURER:Forrest Manufacturing Co. 
AVAILABLE FROM:Lee Valley
RETAIL PRICE:$112
MODEL #:WW10407100
MADE IN:USA
Carl Duguay, May 2012
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