Riving knife design

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Forum topic by Budk posted 02-26-2013 09:09 PM 1434 views 0 times favorited 6 replies Add to Favorites Watch
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8 posts in 1942 days

02-26-2013 09:09 PM

I’ve got a Powermatic 65 saw and I’d like to add a riving knife to it as well as a blade guard. If I understand it right, a riving knife should be the same width as the blade, be mounted as close to the blade as possible and move in tandem with the blade. Correct ?

I don’t think I’ll have any luck finding one that is made to work with my saw… the model 65 preceded the model 66. Anybody else own the same saw and have any suggestions ?


6 replies so far

View PurpLev's profile


8535 posts in 3648 days

#1 posted 02-26-2013 09:13 PM

check out the BORK (bolt on riving knife). it’s a third-party accessory that simulates a riving knife for older built saws that do not have the standard riving knife mechanism built into their saw.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View kdc68's profile


2657 posts in 2277 days

#2 posted 02-27-2013 12:31 AM

+1 on Bork…..riving knife should be slightly narrower than the kerf…(width of tooth + blade runout) and yes it moves as the blade moves , up and down and angles

-- Measure "at least" twice and cut once

View Budk's profile


8 posts in 1942 days

#3 posted 02-27-2013 02:01 AM

Thanks…. not sure why the BORK is so expensive…. seems like it will be easy to fab one up.

View runswithscissors's profile


2752 posts in 2025 days

#4 posted 02-27-2013 05:59 AM

Check out my blog “Riving Knife retrofit for Unisaw.” It’s a quite recent post. I don’t know if your PM has innards similar to the Uni, but it might give you some ideas. I also cite a couple of other bloggers who built their own. Mine is for a right tilt saw, but you could just do a mirror image for a left tilt.

The BORK is not a true riving knife, in that the knife is at the outboard end of a long swing arm. That means that (if you don’t adjust it to the blade height every time you change cutting depth) it’s higher than the blade at full up, and drops below the table well before the blade drops away. Of course some people just set it at an intermediate height and leave it there.

But my main issue with the BORK is that it doesn’t look like a very robust setup. There are a number of posts about the BORK. Use the topic search box at the upper right corner of the window. You might find more info in the “Reviews” section.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View knotscott's profile


8016 posts in 3375 days

#5 posted 02-27-2013 11:18 AM

The BORK is now made from stainless steel and is much sturdier than previous aluminum models. I sure don’t change the height of my BORK everytime I change blade heights….it’s pretty rare that I do, and only takes a few seconds. It could be moot point though….I don’t know if it’ll fit the PM65. Bob Ross could tell you.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View Budk's profile


8 posts in 1942 days

#6 posted 02-27-2013 01:20 PM

Whether or not it fits is moot – I’ll fab my own given the price.

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