Second Feather Board

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patlaw

Mike
Corporate Member
Take a look at Gregory's use of the second feather board. If you look carefully at 4:55, it causes the cut to close up around the blade. The riving knife is there, but I have to wonder if it's a good idea to use the second feather board.

[video]https://youtu.be/spotCL6y_7c?t=4m49s[/video]
 

ehpoole

Administrator
Ethan
I never use a horizontal featherboard anywhere behind the leading tooth of the blade — in fact, I usually stop about 1/4” before the blade’s leading tooth specifically to avoid applying any lateral pressure to the kerf or blade as that can cause kickback by either closing the kerf or pushing the stock laterally into the sides of the blade’s teeth.

However, for higher risk cuts or precision cuttIng of very thin or ungainly parts I will sometimes place a vertical featherboard behind the blade, attached to my fence, to ensure that no kickback can occur since it will provide strong resistance to any upward/lifting motion of the stock forcing the blade to cut into the wood, which will relieve the pinching force, rather than throwing the stock if a kickback event were to initiate. Since the vertical featherboard resists the kickback even as it tries to lift and eject the board it stops the kickback in its tracks, and because it does nothing to close the kerf nor applies any lateral pressure to the cut it will not contribute to causing kickback — it solely adds control and a greater degree of safety.
 

Jeff

New User
Jeff
it causes the cut to close up around the blade

That's not correct, it's not the second featherboard. The riving knife is doing its job and that closing up is just stress relief in the board that would happen anyway.

I think the blade kerf would have closed without either featherboard. The riving knife alone is doing its job and I suspect that the kerf that's closing is already past the riving knife while the uncut trailing edge of the board is still engaged with the blade. Mr. Paolini comments on the riving knife doing its job at about 4:51. Note, the long push stick is also helping to hold the board flat on the saw table which not only protects his hands but prevents the board from rising and kicking back.
 
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Mike Davis

Mike
Corporate Member
You can see the kerf close up right when it hits the second feather board. It is open before that.
 

Jeremy Scuteri

Moderator
Jeremy
That's not correct, it's not the second featherboard. The riving knife is doing its job and that closing up is just stress relief in the board that would happen anyway.

Absolutely wrong. It is very obvious, the kerf starts to close up right when the board hits the 2nd feather board. You can easily see this in the video, just look at the timing of the events.
 

Pop Golden

New User
Pop
Yea Mike, I see it closing. I only use feather boards on the table saw when they are needed. I'm far more likely to use a vertical board than a horizontal one. My push sticks handle the lift & fence contact 90% of the time.

Pop
:kermit:
 

Charlie Buchanan

Charlie
Corporate Member
To me burning is a sign of an unsafe condition. The saw is not cutting in alignment or the board has internal stress. The riving knife may prevent a bad accident but that amount of burning means there is a problem somewhere that needs attention.
 

JimD

Jim
Senior User
I agree that bandsaws are better for resawing for several reasons - thinner kerf, greater capacity, etc.. But I don't have one at the moment so I would use the table saw if I were to do it.

I rarely use a feather board on my table saw but if I do, it is in front of the blade, not behind. I agree this is a bad practice. It's hard to tell but I think the burning is primarily on the second cut where the closing of the kerf occurred. It may thus be a direct result of the second feather board.

I lieu of feather boards, I have a wheeled arrangement that applies downward pressure and the wheels are angled a little towards the fence to help prevent the stock moving away from the fence and preventing kickback. But they wouldn't work for a resaw cut (and I'm not sure where they are at the moment - haven't used them in awhile).

I think it was a good practice to use the first feather board but then he got a little overboard with the second one.
 

Mike Davis

Mike
Corporate Member
I have worked on several SawStop table saws. They are high quality, well built machines.
However, they are not always perfectly adjusted from the factory.
I have found blade to miter slot adjustments from .005 inch left at the rear to .015 right at the rear of the blade.
The adjustment mechanism is rather easy and robust, it should stay after you tune it into alignment.
I like to see the blade dead zero to the slots and the fence .001-.002 away from the blade at the rear of the table.
Burn marks are usually a clue that the blade may be out of alignment or the fence is out of alignment.
 

patlaw

Mike
Corporate Member
My miter-slot-to-blade alignment is off by .015" based on my measurements. I have to do some more testing to make sure that some of the error is not caused by the blade, but I'm learning how to do that.
 

Jeff

New User
Jeff
Absolutely wrong. It is very obvious, the kerf starts to close up right when the board hits the 2nd feather board. You can easily see this in the video, just look at the timing of the events.

4:53 the top of the cut is starting to close and the bottom part is still open but it hasn't touched the featherboard yet

4:54 still not to the featherboard (look closely at the end grain), but the top is closing along the top kerf and the bottom is still open

4:56 featherboard is on the edge of the board, the top has closed but the bottom is still open

5:00 ditto

Minor points and minutiae I guess, so just don't use the second featherboard and move on.
 
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patlaw

Mike
Corporate Member
Oops. I should have read the comments to the video. They're all over him for putting in the second feather board.
 

Jeremy Scuteri

Moderator
Jeremy
4:53 the top of the cut is starting to close and the bottom part is still open but it hasn't touched the featherboard yet

4:54 still not to the featherboard (look closely at the end grain), but the top is closing along the top kerf and the bottom is still open

4:56 featherboard is on the edge of the board, the top has closed but the bottom is still open

5:00 ditto

Minor points and minutiae I guess, so just don't use the second featherboard and move on.

It is just so obvious that the most significant change in the kerf occurs when the board hits the 2nd featherboard, I am surprised that this is being debated. It's okay to be wrong. It happens to all of us. :)
 

Jeff

New User
Jeff
Oops. I should have read the comments to the video. They're all over him for putting in the second feather board.

No problem. You started a good discussion for good reasons and the collective view is "don't use the second featherboard".
 
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