Riving Knife questions........

[Roy Wall]

SMC -

I looking into the features of these RK's....... I realize they are a great anti-kickback feature when ripping.....

How often can you leave these things on??? Can you use them on a CC sled? Make shoulders for tenons? Make tenons (upright or series of cuts with 1/8" blade?? Cutting grooves on edge..... etc. etc....

Thanks guys!

[Alan Turner]

Yes as to all of your questions, I beleive, as the knive is tight to the back of the blade, but below it a drop, and goes up and down as the blade is raised or lowered.

[Michael Perata]

Alan

I think a riving knife following the blade is machine specific.

I installed a Bies riving knife on a Jet cabinet saw I had a while back and it was stationary. I believe there are two styles of Delta/Bies riving knives, one moving with the blade and one not.

I have a riving knife on my MiniMax that moves with the blade and it NEVER comes off except when I use a dado setup.

[Sam Chambers]

Michael, that wasn't a riving knife. Biesemeyer doesn't make one. None of the U.S. saw companies makes a saw that can use a riving knife, although I'm really surprised that some mechanical genius hasn't figured out how to retrofit one on a Jet, Delta, Powermatic, etc. In fact, the only table saw made in the USA with a riving knife (although an unusual one) is the Shopsmith. But calling a Shopsmith a table saw is a bit of a stretch.

One of the most appealing things about the SawStop table saws is that they were designed to have a true riving knife, like the european saws have. Much safer, IMHO.

Someone in the tool selling business once told me that he asked his Delta rep about making their table saws safer. The rep said that they could, but the legal department wouldn't let them. Not that the new saw wasn't safer, because it would be. The lawyers were worried that if they changed the design, the marketing guys would want to advertise it as a "safer table saw". If they did that, it would be basically admitting that the older saws still in use were "unsafe", and the owners of the older saws would sue them every time there was an injury!

[roy knapp]

Hi Roy:
A riving knife most definitely should be used when ever ripping. The riving knifes job is to prevent the wood from closing back, up pinching the blade after it has been cut. If a riving knife were not being used an the wood did pinch the blade, most likely a kick back would be the result.
As anyone can tell you this could realy create some bodily damage. If you are lucky maybe the board only went through the shop wall.
Ripping is where the riving knive realy is need and anti kick pawls.
I never use mine with the cross slide sled, as this is a cross cut operation and does not seem to present a problem.
Anytime i have to rip, i change blades and setup the riving and anti kick pawls. I also change from the zero clearance throat plate. this may sound like a lot of extra time, but its alot less time than i would spend in the Emergency room.:)

safety first

[Frank Hagan]

Someone in the tool selling business once told me that he asked his Delta rep about making their table saws safer. The rep said that they could, but the legal department wouldn't let them. Not that the new saw wasn't safer, because it would be. The lawyers were worried that if they changed the design, the marketing guys would want to advertise it as a "safer table saw". If they did that, it would be basically admitting that the older saws still in use were "unsafe", and the owners of the older saws would sue them every time there was an injury!

I work quite a bit with products liability law (although I'm not a lawyer). In many states it is not admissible to introduce a product improvement as evidence that a product was inferior before, unless they already establish that the product was inferior to some industry standard. In any case, in some states "strict liability" applies, so you don't even have to show that the product is unsafe, defective, or that the manufacturer failed to warn the consumer ... if your product hurt them, you are at fault. Doesn't matter how. Now that SawStop has come out, the other manufacturers are probably in a bad position, and ... were I working for them ... I would recommend they come out with a similar system.

I suspect the real reason is that the manufacturer realizes the market for a $2500 table saw is a lot smaller than the market for a $700 table saw.

Anyway, I'm not sure I understand the functional, real-life difference between a splitter and a riving knife. I do understand that the splitter is fixed, and the riving knife moves with the blade carraige and can therefore be positioned much closer to the blade. But what is the advantage of that? Does it do more to prevent the stock from riding up on the back of the blade?

[John Renzetti]

. Anyway, I'm not sure I understand the functional, real-life difference between a splitter and a riving knife. I do understand that the splitter is fixed, and the riving knife moves with the blade carraige and can therefore be positioned much closer to the blade. But what is the advantage of that? Does it do more to prevent the stock from riding up on the back of the blade?
hi Frank, Both the splitter and the riving knife help to keep the cut workpiece from closing up and pinching the blade. The splitter is usually fixed and the ones I've seen are part of the blade guard. The big problem with a lot of splitters is that they can be removed and then never put back. A good riving knife as found on European saws can be adjusted depending on the blade size. (I like mine about 1/8" behind the blade on my Felder Format 4 saw.)
The riving knife also moves in the same plane and axis with the main blade. For European saws without the very large and heavy overarm saw guards, the riving knive is a place for the saw guard with dust collection, to be attached. Except for Dado operations my riving knife stays on the machine at all times. Since it is so easy to re install and adjust I have no excuse for leaving it off.
take care,
John

[lou sansone]

[QUOTE=Sam Chambers]Michael, that wasn't a riving knife. Biesemeyer doesn't make one. None of the U.S. saw companies makes a saw that can use a riving knife, although I'm really surprised that some mechanical genius hasn't figured out how to retrofit one on a Jet, Delta, Powermatic, etc. In fact, the only table saw made in the USA with a riving knife (although an unusual one) is the Shopsmith. But calling a Shopsmith a table saw is a bit of a stretch.


Hi sam
The rockwell delta RT-40 has a RK feature. This is not a very popular saw due to the cost and size, but it is american ( well made in brazil ).
here are the pictures of my saw with one installed.

http://www.sawmillcreek.org/showthread.php?t=18836 the RT-40


http://www.sawmillcreek.org/showthread.php?t=19825 the RK installed

lou

[Roy Wall]

Thanks for the feedback!!!

So, why do you ( or just DO YOU) need BOTH the RK and a splitter w/ pawls?? I see that sawstop comes with a Riving Knife.........and also with a splitter/pawl/blade cover combination.........

Why these combinations.......??? Why not just a RK and that's all you need??

[lou sansone]

riving knife and pawls is sort of like "belt and suspenders". I simply feel that all I need is one of them, not both. In my case I use the RK and that seems to be fine

lou

[Bill Simmeth]

None of the U.S. saw companies makes a saw that can use a riving knifeWell, as Lou already pointed out, American saws have been offered with riving knives in the past. Truly American-made saws such as Oliver and Fay & Egan offered real riving knives years ago. It's not some sort of modern-day European brainstorm. Problem is we, the American consumers, have always just been cheep bah-studs and refused to pay a premium for quality, safety-oriented products -- something I'm I afraid SawStop will learn the hard way...

Cheery Bill in Delaplane, VA

[John Cavanaugh]

None of the U.S. saw companies makes a saw that can use a riving knife

The Laguna table saw has a riving knife, or are they not considered American??

--
John Cavanaugh

[Norman Hitt]

The Laguna table saw has a riving knife, or are they not considered American??

--
John Cavanaugh

All Laguna's tools are Imports, and the saw you refer to, John, I believe is made in Belgium, but possibly another European Country. Different tools of theirs come from different places.

[Frank Pellow]

The Laguna table saw has a riving knife, or are they not considered American??

--
John Cavanaugh
The defination of an "American" saw is not at all clear. I believe that the Laguna table saws are made in Romania.

[Sam Chambers]

Lou and others...

I stand corrected. Now, please excuse me while I pry my foot out of my mouth.... :o

[lou sansone]

hi sam


hey no problem on the correction thing. you were right in a general sense, but we managed to sneak some exceptions to the rules in just for good measure :rolleyes: :rolleyes:
lou