What in the world is a riving knife? Just the one thing that might save you from a very bad day in the shop. But if your table saw doesn’t come with one, fret not — with a little wherewithal you can add a riving knife to almost any table saw.
For those who have never experienced kickback on a table saw, we can assure you that at a minimum it will set your heart pounding. At the worst, it will suck your hand into the spinning blade and send your fingers flying, or perhaps embed a piece of wood in your chest or forehead. Riving knives mitigate such catastrophes by preventing the stock from touching the blade as it rotates up out of the table. Contractor table saws like [Craft Andu]’s little Makita are often stripped of such niceties, so he set about adding one. The essential features of a proper riving knife are being the same width as the blade, wrapping closely around it, raising and lowering with the blade, and not extending past the top of the blade. [Craft Andu] hit all those points with his DIY knife, and the result is extra safety with no inconvenience.
It only takes a few milliseconds to suffer a life-altering injury, so be safe out there. Even if you’re building your own table saw, you owe it to yourself.
For some BS reason we had to remove them from the high school shop table saws.
Come to think of it, table saws belong to the steam and belts age along with bulky motors made for continuous use. I think it makes sense to have two handgrips opposite of the blade with the stock held in place.
I would like to see a hack for a rail guided portable saw and drive. Place stock line under laser line and clamp down. Press run! Table only has to be as big as the stock, not twice as long for safe motion as with a table saw. Balancing the stock and moving it on that table is asking for trouble and sloppy cuts.
Couldn’t agree more, except many of those cuts could be done on a table version of the shown item.
Isn’t that called a radial (h)arm saw? A good miter saw will do that too.
For table saws just use sleds .At a minimum you should have a crosscut and 45* miter sled. Then there’s all the custom jigs for box joints, tenons or less common cuts.
As others have pointed out panel saw are very useful for breaking down sheet goods but cheap ones can be a bit limited in their cuts.
That would be a radial arm saw.
Check out the Mafell Erika, which is a super-nice (German) contractor table saw, basically, except the saw is on a rail so you can either push your work through as usual, or pull the blade through the stationary work. This video, https://www.youtube.com/watch?v=G77IdRXxyyI&t=5m00s for instance. I want one very much. Automating the pull is up to you.
For big cuts, a circular saw on a guide is hard to beat. See Festool, but also Bosch or others. Is this a German thing?
This isn’t about adding a riving knife to a saw without one, something I’ve yet to see anyone do… It’s just about replacing the stock riving knife with a custom one.
It’s kinda like you didn’t actually read the source you linked to.
Agreed, dude modified his existing knife, which isn’t the same thing.
There used to be a product called the BORK (bolt on riving knife) that seems to have gone away when the owner had a health problem.
Here’s a blog entry with somebody modifying a old Delta Unisaw to take a riving knife.
https://thewoodenscrew.blogspot.com/
Yes, bad title, he’s replacing an existing riving knife, not real helpful. I need to add one to my say as it has something similar but its behind the table so too far from the blade to do anything. But to do so I’m going to have to cut a slot in the table.
I was REALLY struggling with understanding how THAT video demonstrated the safety feature. In fact, it seems to REDUCE the amount of safety it provides.
This isn’t really “adding” a riving knife, its more like modifying or replacing a riving knife.
It’s a good idea and a good video. But it doesn’t help me with my saw that is too old to have a riving knife mount.
Ok, I use table saws all the time and there are 2 primary things that will keep your fingers on your hands.
1) throw away all your push sticks and make a pistol-grip style push stick like this (only wider):
http://wwwcdn.popularwoodworking.com/wp-content/uploads/IMG_2850.jpg
This keeps the piece pushed down and forward instead of just forward while you’re cutting,
2) as soon as the cut is done turn off the saw and put your hands behind your back until the blade stops.
Lastly, never ever stand in the path of the piece being cut.
I’m not sure that will keep a piece down during a kickback, it’s not called a-gentle-pushback right?
I mean all the power of the saw is having at it.
Kick back is a multi-step process which starts with the blade getting an unexpectedly larger chunk than the last chunk it took. But that unexpected chunk is just a little more. If it stops there then the action isn’t amplified into a runaway. If the user is paying attention, the push stick prevents that amplification.
The usual kickback cause is a piece of material caught between the fence and the blade. If you let a little cut-off sit there you can watch as it vibrates for a while before suddenly catching and rocketing out. The other cause is the work going crooked or internal stresses pinching the blade so a lot of the exposed blade is suddenly buried in the work. I’ve only had one of those while using a small amount of exposed blade to shave a chunk of PVC. Got a pretty good launch on that, but was standing to the side in preparation.
The worst case is to be in a position where the user’s hands are aligned with the blade and the work suddenly disappears, causing the user to try to press the now gone work harder to stop it from moving, but instead finding the blade where the work used to be.
Link didn’t work for me… this did http://www.popularwoodworking.com/wp-content/uploads/IMG_2850.jpg
I got kicked in the chest once by a 2 by 4. No lasting damage, but man was it surprising.
back in woodshop a fellow student had a saw kickback that jerked the piece out of his hand and tossed it across the shop. he managed to not run his hands through the saw, but absolutely terrifying.
Was ripping down 4by stock into 2x stock for lathe practice material six or so years ago. A riving knife would have been very helpful when the blade decided to lift the piece between the fence and blade up and over, out from underneath of my push stick, to land on top of the spinning blade. 2x2x8 piece of Brazilian mahogany hitting you end on just above the navel at god only knows what speed does NOT feel good. I was lucky I was wearing a heavy cotton t-shirt and buckled with the hit or I likely would have been impaled. Had a 2″ diamond bruise on my stomach for weeks. Finally had the resulting umbilical hernia repaired last summer.
I grew up doing woodwork, and am not a novice with a table saw, or any other large shop power tool. Accidents can happen to the most experienced of us, and when you least expect it, even when you do everything right. I’ve learned the hard way that safety features are not something to skimp on.
This is wrong -and in my opinion possibly dangerous.
The riving knife thickness should be thicker than the body of the blade you are using but thinner than the kerf (resultant cut in the wood).
See HSE UK government safety information on Table saws for correct illustrated explanation at to why this is.
Page 3 of https://www.hse.gov.uk/pubns/wis16.pdf has an illustration regarding riving knife thickness as you describe but it doesn’t explain why.
Here are their pages on woodcutting machinery safety: https://www.hse.gov.uk/woodworking/woodcutting.htm
Adding a riving knife to an old table saw is an easy and inexpensive way to increase safety and accuracy. This guide will provide step-by-step instructions to add a riving knife to your existing table saw, as well as tips for selecting the right type of riving knife for your needs.
A riving knife can be an effective safety feature for a table saw, as it can help prevent kickback and blade-related accidents.