TS Blade recommendation....riving knife is .90

[George Farra]

Hi Everyone

I recently picked up a Bosch 4100 TS. I'd like to upgrade the blade and am torn between a quality combo blade or a dedicated ripping blade and crosscut blade.

To add technicalities to the equation, the rivink knife is .90 in thickness so the blade needs to match.....how close does it need to be?? Between Freud and CMT I found blades between .91 and .94.....will they work??

Fine Woodworking tested combo blades and the Oldham was thier favorite which is listed as .90 on thier website.

I plan on using the saw to first build shop cabinets, but then move onto woodworking projects....jewelry box, child's toy box, foyer table. From thier I want to start moving into other furniture projects for the wife/house.

Thouhgts and recommendations would be great. Also, which stacked dado set would work best with this saw?

TIA

George

[Prashun Patel]

I have a Freud Avanti 50t Combo. It was cheap, and it cuts fantastically cross and rip. I've used it to excellent effect in pine, eucalyptus, cherry, and birch plywood (although I have to admit that I taped my plywood cross cuts and used a ZCI or sled).

If I had serious coin, I'd get the Freud Fusion.

[Tom Esh]

I mostly use a Forrest WWII thin kerf (3/32 ~ 0.09375) 30-tooth on my Bosch. I started with the 40-tooth, then picked up the 30-tooth on sale when I had a bunch of 8/4 to rip. If I had to choose one, it would be the 30-tooth. Better rip performance and the crosscut quality is nearly the same. I'm happy with the Forrest, but when it needs sharpening I may try a Freud. Of course I also have the usual stack of el-crappo OEM blades for mdf and other junk. No idea on dado sets. I do mine on the RT.

[Richard Magbanua]

Congrats on the new TS!! I like the new riving knife, too. Much safer.
With regards to the knife, someone correct me if I'm wrong, it doesn't need to be the same thickness, just not thicker than your blade. The important part of its operation is that it is flush with the fence side of your blade so that it keep your stock against the fence after the cut. This prevents kickback by keeping your wood from being picked up by the back half of the blade, pinching it against the fence and throwing it toward your face. I have mine adjusted so that it slightly pinches the wood against the fence.

As for combo vs. dedicated blades I chose to get two blades. Mostly because they were on sale (Freud glueline rip and their combo blade). I got the combo blade because It seemed to be good enough for most any cut with regards to joinery or final sizing. I read a review somewhere that a higher-end combo blade could cut close enough to a crosscut blade. This seems true for my standards at least. I later realized I when I was ripping stock for projects I would do most of this at the same time. I got the glueline rip blade to keep the wear tear down on my combo blade as well as my saw. It was a significant improvement in the ease of cutting and the cut quality was ready for glue up as advertised. The freud blades can go on sale for around 50 bucks sometimes so keep an eye out.

[John Thompson]

"With regards to the knife, someone correct me if I'm wrong, it doesn't need to be the same thickness, just not thicker than your blade. The important part of its operation is that it is flush with the fence side of your blade so that it keep your stock against the fence after the cut. This prevents kickback by keeping your wood from being picked up by the back half of the blade, pinching it against the fence and throwing it toward your face. I have mine adjusted so that it slightly pinches the wood against the fence"... Richard
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Actually Richard.. the riving knife has to be a bit thinner than the keft (tooth) of the blade to allow the wood to pass as you mentioned and that is correct. But it's purpose is when you have reaction wood (stock containing much internal stress that releases when you sever it) it doesn't close back and pinch on the rear rising teeth which is the most dangerous portion of your spinning blade.

But... I will add that since it has to thinner than the kerf to allow wood to pass it.... you could still get kick-back if the internal stress is very severe as there is a variance in distance of the knife and keft with the kerf standing proud of the knife. That kick-back is known by some of us that have been using riving knives long before the current attention that has been given to them here in the U.S.

So... it is just one thing of several that can help eliminate kick-back. If internal stress is extreme as mentioned... what happens if the stock spreads instead of closes? What happens is it can hit a long fence and rebound back into the spiinning rear teeth because the knife has to be a bit thinner than the kerf.

That's where a combination of short fence (a fence that doesn't go beyond mid blade allowing a free zone as the cut is alway complete at the end of stock before it reaches that point) and riving knife used in combination eliminates (almost but not entirely) two of the ways kick-back can occur.

So... wise to not be lulled to sleep thinking you have kick-back covered by simply having a riving knife alone. You might be in for a surprise and if you use your saw a lot and get hold of some real reaction wood the chance rises sharply.

Hope that helps you understand the function a bit better...

Sarge..