# Home made riving knife



## TTalma (Jan 12, 2011)

I have done a lot of searching for info on a homemade riving knife. and I've seen a lot of things people pose as riving knifes, but are just improved splitters. So I have been working one the last few weeks. I just finished my proof of theory prototype the other night. A friend mentioned that I should post this on Lumber jocks. So if anyones interested in following my project I have some posts on my blog. Feel free to check it out and if you have any design improvements please let me know.

http://thewoodenscrew.blogspot.com/

There is even a video of the prototype in action.


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## IrreverentJack (Aug 13, 2010)

Thank you for posting this. I'll be following the updates on your blog. -Jack


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## PurpLev (May 30, 2008)

very cool. looking forward to seeing this produced.


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## jgreiner (Oct 23, 2010)

Amazing design, make me one!


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## IrreverentJack (Aug 13, 2010)

Tim, Nice! Works as good as it looks. Thanks again for posting this. -Jack


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## BillWhite (Jul 23, 2007)

I'll want one for my Grizz 0444Z. Next week be OK?
Good work, and I think that your machining is just fine.
I was wondering when someone would come up with a retro-fit for existing saws. Am I just dreaming?
Bill


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## BorkBob (Jan 11, 2011)

Tim, that is one awesome effort. Having spent a lot of time with my hands and head inside a saw like that, I recognize just how briliant your design is.

Maker the install user friendly for the average woodworker and stand back because they will beat a path to your door.


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## BorkBob (Jan 11, 2011)

Tim, that is one awesome effort. Having spent a lot of time with my hands and head inside a saw like that, I recognize just how briliant your design is.

Maker the install user friendly for the average woodworker and stand back because they will beat a path to your door.


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## tierraverde (Dec 1, 2009)

Tim
Great job and great blog.
You must have a machining background. It shows.
My only criticism is your website. Can you change the black background? Sites like these are really tough on the eyes.


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## Alexdi (Oct 22, 2011)

Very interested, to the tune of polishing my credit card. Nicely done.


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## barrys (Apr 20, 2012)

Beautiful work. Did you happen to keep track of and would you be willing to share some of the critical dimensions of the different parts. I've got a small mill and lathe and I'd be hard pressed to get my parts coming out that nice.

Also, do you think aluminum would work for the round bracket you milled out of that thick steel rod? I have that in aluminum so why not ask. Probably too soft for something so thin.


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## TTalma (Jan 12, 2011)

Thanks for all the nice comments. I do have a sketchup model of the knife. if you would like a copy of it here's a link to it: http://dl.dropbox.com/u/14006061/Riving%20Knife/Riving%20knife%20final.skp


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## gulfislandguy (May 16, 2012)

Hi Tim, I'm new to LJ - I was so impressed with your work on this project - it motivated me to join up! Somewhere in the text you mentioned that someone would have to modify this for a 10" Unisaw - has that been done to your knowledge? Have you ever compared the guts to know how adaptable your design is to the more common saw? I recently acquired a 1973 Guelph ON produced Rockwell Uni and would love to add your riving knife to it. Do you plan to offer this as a commercially available product?


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## Vrtigo1 (Mar 18, 2010)

That is very cool, nice to see someone solving the problem of adding a riving knife to older saws.


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## TTalma (Jan 12, 2011)

Gulf I have checked into the guts of a 10" saw and they are exactly the same (for the older unisaws anyway). They are just a little smaller. If someone has made this for a 10" machine I have not seen it yet. I have no plans to make this into a comercial product. I offer it freely to anyone who wants to make one for themselves!


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## atmartin (Apr 27, 2014)

Tim,

I really like your riving knife design! I was looking at making a similar design for my 10" unisaw. My only question (currently) is how did you remove the blade? Perhaps your saw is different from mine but the castings looks very similar. The Arbor on my saw has flats for a wrench. It appears that if i install the components of the riving knife onto the arm around the arbor, it will stick out enough that i will not be able to access the flats on my arbor. Did you have the same problem?


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## runswithscissors (Nov 8, 2012)

Tim did a beautiful job on his riving knife. I came up with my own approach some time ago, and it addresses the concern you have (being able to use the arbor wrench). The blog is called "retrofit riving knife for unisaw". If I knew how to put the link in here, I'd do it. But you can look it up easily enough. There are 2 blogs, by the way. Use the one with the above title, as it is later and more complete. Follow it to the end, as it evolved over a period of time.


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## hairy (Sep 23, 2008)

Here's your blog.
http://lumberjocks.com/runswithscissors/blog/34688

How old is your older Unisaw? If that's in your blog, I missed it. That looks like a good RK. Thanks!!


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## TTalma (Jan 12, 2011)

My saw is from 1952. Most of the older unisaws are pretty much identical inside. Mine takes a 12 or 14" blade, and is basically just a bigger version of the unisaw. I'm not sure what you mean by flats on the arbor. I remove my blade by putting a scrap of wood across the table so the teeth hook on it, then take the arbor nut off. It sounds like you use 2 wrenches. My design is about an 1/8" from the arbor flange so I doubt you would be able to get a wrench in there.


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## unbob (Mar 10, 2013)

The Rockwell/Delta 12"-14" is no Unisaw, much heavier built machine and shares no parts. Around 400lbs more weight.
A nice feature is the threaded part of the arbor is removable. Though Delta never offered it, a 5/8" arbor can be purchased from Grizzly, the same arbor type was used on their G5959 12" saw. There is no wrench flat on the 12-14 arbor.
Unisaw users tend to over-tighten the blade because it has the wrench flat.
Another difference is the 12-14 uses a base mount motor, instead of the hanger bracket on the Unisaw.
The slick riving knife design here maybe could be adapted to a Unisaw, but, the arbor bracket casting is much smaller and thinner at the bearing location.
Nice job on the design, and you have a really nice metal lathe, in fact its world class.


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## TTalma (Jan 12, 2011)

Thanks, that's a few things I didn't know about my saw. I always assumed the 10" unisaw was the same, just smaller castings. The motor is labeled a 3hp and weighs a ton! it's bigger than the 5hp baldor in my planer.

I wish the metal lathe were mine it belongs to the company where I work. It has a special cross slide on it that makes it more accurate than a a standard lathe. It's from their High accuracy line. The company has the receipt for it. in the late 80's the lathe was about $8k, and the cross slide upgrade was $24k! Then there was all the tooling on top of that. It was used for making rotors for attack helicopters. The mechanical tech has been replaced with digital and fiber-optics, so now the lathe is in the tool room and only used for day-to-day type stuff.


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## PogoCornEater (Dec 12, 2014)

Tim,

I realize the dropbox link is old. Do you still have any files available?

I would definitely be interested in trying to scale down a 10" Unisaw Version. We have a small CNC Job shop and my youngest son is a CAD design engineer for another company. If we had a starting point with a couple of known dimensions, I am confident we could come up with a workable version.

I have had three kickbacks in the past few years, all of which found their target. . . me. I could really use a Riving Knife. Delta clearly isn't interested in retrofitting, as it would negatively impact new sales from people wanting to upgrade their safety features.

I have considered installing a power feeder, but sacrificing the real estate and losing some flexibility is hard to do, when there are riving knife alternatives available. I applaud your willingness to share for those of us looking to achieve the same results you have.

Dave


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## barrys (Apr 20, 2012)

I think I have all the files. I at least have the cad converted to many formats. Send me a pm with your email.


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## drm11981 (Apr 9, 2017)

could you send me a copy of the files as well? I am very interested.My email is [email protected]

Thanks.


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## redheadedwoodpecker (Jan 11, 2019)

I would also be interested in the cad files if you have time, just got a cnc a few months ago I would like to attempt a more complex project. And my 20 year old saw could use an upgrade.


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## barrys (Apr 20, 2012)

I would love to help you. It seems the files I have were widely available and seriously insufficient for a real CAD design accurate enough for CNC toolpath generation. I'm not sure i even still have the files. PogoCornEater was the closest to having real, CNCable files based on the messages I've received. I would consider contacting him. And, I have not added a riving knife to my saw as much as I would love one. I just uses an embarrassing amount of featherboards and protective gear.


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## Veeps (Sep 11, 2019)

Hi. I used to be a member but either my account got deleted for inactivity or I forgot my username/email I use to use. I just picked up a 1983 10" unisaw. It's in great shape. I had to take the top off to transport it home so I figured I should clean it up and go thru everything. I cleaned the inside and lubed everything with boeshield T9, replaced the arbor bearings, and now i'm waiting for new belts. Now I am planning on making a riving knife if possible. Has anyone used this same design. I just saw this other design which I think I will try to replicate, but it's harder to align the mount to be parallel with the blade.

https://www.lumberjocks.com/runswithscissors/blog/34688

There isn't much room around the arbor shaft.



















Both are great designs and I think it's better to build one versus a splitter. 
thanks for any insight.


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