Riving knife with crosscut sled

[ey_tony]

The idea of a riving knife is to stop the gap of the separated ends from closing after being cut to prevent the blade from jamming should the cut ends close. It's similar to using a wedge when making a long cut with a hand saw.
If one is cutting a slot into a piece of wood on a table saw where it doesn't pass through the entire piece then it shouldn't jam so a riving knife isn't essential in that situation and safe if you follow the advice of @Jacob but if not confident with that method then using a router is probable a better option for you.

I personally don't use a sled on my modest table saw and never have used one. Removing a riving knife or blade guard are personal actions. Do whatever you feel is the best option for you to complete the job safely.

 

[Jacob]

Thanks Mike i agree i also cut dados with the router table, i am trying to find a way of using the table saw with a crosscut sled and the riving knife is too high, not comfortable with removing it myself so am on the hunt for a smaller one.

Could make it tall enough to accommodate a slot wide enough to take a riving knife mounted crown guard?
Much better idea: instead of making the cut with the workpiece in front of the fence turn it around so that the work piece is behind it and pressed up to it by clamps or push sticks. That's how I do it with my sliding table. A bit counter-intuitive at first but in fact much easier to handle and safer as your hands do not have to go anywhere near the blade or to reach past it.

 

[matt carpenter]

The idea of a riving knife is to stop the separated end from closing after being cut to prevent the blade from jamming should the cut end closed. It's similar to a wedge when cutting with a hand saw.

Thanks that is my thought on it too, therefore i am thinking that it would not apply on a crosscut sled as the sled is held together by the fences and cross cuts are held against the front fence so can not get trapped or bind on the blade. what do you think?

 

[bryan267]

I have that table saw, I'm always taking the riven knife off to make tenons. I don't like the riven knife as it has a lot of play before you tighten it and can lay on the blade. So be careful when refitting it.
I have bought and not yet fitted the micro jig table saw splitter, might work for you.

https://www.microjig.com/collections/mj-splitter

 

[hlvd]

I bought an additional standard riving knife for my Makita and followed this hack to cut it down to size. Works perfectly.

Sleds are dangerous pieces of equipment and should be avoided at all costs if you value your fingers.

 

[fiveforty]

The way I look at it is you have 3 options:

1. Use the sled without the riving knife

2. Buy a second riving knife and cut it down smaller
Keith Brown did similar -

3. Cut through the sled once without the riving knife, then with either a saw, router, chisels etc, extend the kerf cut in the fence so that the riving knife can pass through. This is what I did (I have a DW745), the extended kerf cut doesn't affect the accuracy as it is higher than the blades max cut height

You do have to make sure that your fence is high enough that there is enough 'meat' above the new kerf line.
If not you'll have to either put on a new taller fence, or go with option 1 or 2

 

[Agent_zed]

Sleds are dangerous pieces of equipment and should be avoided at all costs if you value your fingers.

would you be able to explain why you believe this?

It would seem to me to be less dangerous to have a sled that can only move forward and backwards hold a small workpiece in place whilst cutting, rather than try and push a loose workpiece through with sticks where it can get jammed on the fence or fire backwards if it catches?

 

[ey_tony]

Thanks that is my thought on it too, therefore i am thinking that it would not apply on a crosscut sled as the sled is held together by the fences and cross cuts are held against the front fence so can not get trapped or bind on the blade. what do you think?

My saw table's riving knife is fixed to the blade height so I have no alternative than to use it if I don't choose to remove it. I can see the benefits of a sled but I've never thought it worth my while to use one so each to their own.
If I wanted to cut a non-through slot them I'd use a router or my hand held circular saw but I wouldn't be afraid to remove the riving knife of the table saw if there was no other option or I needed to make many cuts.
Do what you feel happy with. Just like using blunt cutting tools, lack of confidence with power tools is a sure route to getting hurt. Just use common sense and you'll make the right decision.

 

[hlvd]

would you be able to explain why you believe this?

It would seem to me to be less dangerous to have a sled that can only move forward and backwards hold a small workpiece in place whilst cutting, rather than try and push a loose workpiece through with sticks where it can get jammed on the fence or fire backwards if it catches?

It just goes against everything I’ve been taught really, and there’s always a better tool than a sled.

If you had a sled with an open end with space for the riving knife to pass through whilst the crown guard was still attached it might be ok, otherwise I wouldn’t recommend one.

 

[Jacob]

It's easier the other way around. I use my sliding table and fence as per photo - left hand and push stick (or 2 push sticks) pushing workpiece to fence and sliding table. Both hands well away from the blade and no leaning over.
If I needed a sled I'd do it the same way - base plate plus one fence on far edge
You'd then only cut into the base of the sled as far as you needed and not right through as with the designs with the fence on the nearest edge - a very basic design mistake.
Could mock one up if anybody doesn't get it?

 

[Lefley]

Take off the riving knife, cut with workpiece firmly held against a fence, use two push sticks - one pushes forwards (from somewhere between the fence and the blade), the other pushes in towards the fence, do it in one steady move and don't stop until right through.
Have a practice with some small offcuts?

Anybody that tells a complete newbie to a table saw to remove safety features. Well in the USA you probably would lose your house through a lawsuit after the person injuries himself.

next step probably tak3 off the chop saw blade guard so you can see cut better but keep your fingers out of blade.
the guy is asking for help how to modify a safety device to still be safe, not how to cut after you remove it!,,,,,,,!,,

 

[Jacob]

Anybody that tells a complete newbie to a table saw to remove safety features. Well in the USA you probably would lose your house through a lawsuit after the person injuries himself.

Really? American woodworkers are notorious for dangerous practices in video after video. A joke - they've even had to invent the "Saw stop" because the sil ly boys can't keep their fingers away!
I made the suggestion above because people are likely to try it anyway so one might as well suggest safety measures. Two push sticks as ever - they don't seem very fashionable amongst the Yanks

next step probably tak3 off the chop saw blade guard so you can see cut better but keep your fingers out of blade.

Typical American suggestion, but right about keeping fingers out of the way - well done!

 

[Agent_zed]

It's easier the other way around. I use my sliding table and fence as per photo - left hand and push stick (or 2 push sticks) pushing workpiece to fence and sliding table. Both hands well away from the blade and no leaning over.
If I needed a sled I'd do it the same way - base plate plus one fence on far edge
You'd then only cut into the base of the sled as far as you needed and not right through as with the designs with the fence on the nearest edge - a very basic design mistake.
Could mock one up if anybody doesn't get it?

View attachment 163420

It might be easier but you are only using 1 track for the mitre to run along, so you will have movement in your cut.
You are having to hold the workpiece in your hand so it may move when you cut.
the point of it being held at the back of the sledge is you don't get tear out as the back of the wood is supported
If you have a cheap push stick and you hit the blade they can shatter
your hand is just as near as if you were holding to the edges of a sled, if not nearer.
You cannot remove a hand from either position if things start going wrong as the workpiece is not secured to anything.
In this type of cut the riving knife is doing nothing at all to the cut (except being a mount for the guard)

 

[Agent_zed]

Let's be sensible here, table saws are very dangerous and cause thousands of amputations a year. But I cannot see any evidence that a sled makes it in any way more dangerous, if it does please point to the article/research/video. The accidents I've seen or heard about (and I've watched a lot of videos to educate myself) seem to be due to people holding the workpiece and running their finger through the saw, moving their hand into a spinning blade or having a piece of wood catch and fire it at themselves.

If you have a sled that enbles the use of a riving knife (makes zero difference for cross grain cuts), has a guard over the top, has a guard at the back, has clamps to hold the workpiece and dedicated handles to keep your hands away from the blade I would argue that is far safer than manually feeding small pieces of wood through against a fence whilst pushing it with a stick.

I can't see how it can't be safer? I'm always open to learning but I'm not hearing any actual facts to back up that sleds make it more dangerous so far.

 

[Jacob]

It might be easier but you are only using 1 track for the mitre to run along, so you will have movement in your cut.

Mine is a sliding table - I'm not using the track. If I didn't have a sliding table I might use both tracks and a sled.

You are having to hold the workpiece in your hand so it may move when you cut.

Not if I don't move my hand and push stick. You can't really push the other sort of sled through without holding the workpiece one way or another but you might get away with it

the point of it being held at the back of the sledge is you don't get tear out as the back of the wood is supported

Hmm - not really that well supported.

If you have a cheap push stick and you hit the blade they can shatter

Yep. They are usually made of non shatter plastic, or copied made with mdf or ply. These are good and cheap as chips Axminster Workshop Push Stick

your hand is just as near as if you were holding to the edges of a sled, if not nearer.

No it isn't

You cannot remove a hand from either position

yes you can but one at a time

if things start going wrong as the workpiece is not secured to anything.

If that was likely to be an issue you can clamp to the fence.

In this type of cut the riving knife is doing nothing at all to the cut (except being a mount for the guard)

Yes. That is what it is doing. There's nothing else for it to do!

 

[Orraloon]

I think a lot of you are not taking in just what a riving knife does or in fact what a sled does. A riving knife prevents the wood binding against the blade during ripping with the grain. It is not essential for crosscutting or non through cuts. Nobody minds crosscutting or trenching with a miter saw or says that's gonna have your hand off. In fact I feel safer doing stuff like tenons, box joints and small items on a sled on the table saw than using a miter saw. More accurate too. All up a sled especially with a top guard is a pretty safe item. If your saw is modern with a riving knife that goes up and down with the blade then there is no problem but the older fixed splitter arrangements cant be used with a sled that has 2 fences. Its all choices in the end and as they say if you dont like the thought of doing it then dont do it.
Regards
John

 

[L M Joinery]

Never remove the rife, use a router table for this as others have said. You could end up in A&E or worse.

 

[Agent_zed]

Never remove the rife, use a router table for this as others have said. You could end up in A&E or worse.

There seems to be a lot of assumption as to what the OP is doing.

How would you use a router table to make picture frame mitre cuts? It would be the wrong tool for the job.

clamping a picture frame rail into a 45 degree jig on a sled and running it through the saw is as safe, if not, safer than trying to mitre the end of a piece of wood on a router table?!

For the above job it would make absolutely no difference to safety if you remove the riving knife as it is cross cutting.

I do agree though it is best to make/buy one that you can leave on though as it is easy to forget to refit or 'I'll just do that quick job without it' when using the machine in a different way. Understanding what it does and why you need it is key.

A router table is in itself a hugely dangerous piece of equipment. Partly because it is seen as less dangerous, like my little bandsaw that sounds like a sewing machine but would quite happily cut through a finger. I stupidly had a test piece of wood catch and pull my finger into a biscuit jointer on my router table. Luckily I escaped with only a small scar on my finger to remind me not to be an idiot (or at least be a more careful idiot). They are not a danger free alternative!

A sled is no different in essence to a saw with a sliding carridge. Would you tell people this saw will maim or kill you e Charnwood 8" Cast Iron Table Saw with Extension Tables ? That is doing the exact same thing as a sled.

 

[Ttrees]

There's also option to make a positive stop for a sled.
Seen some ideas on YT before, but they don't appear trustworthy atall,
but the idea is there for someone who might be of the opinion that their fingers are more important
than the work, and it's up to them to make things safe, and not just for this week.

i.e, cleats and screws used for something which gets bumped, are likely to come loose sometime.

If I had one of those little ripping machines, I'd be welding up a hefty metal cage around it of sorts,
and I could hang infeeds and outfeeds from it, and whatever else needed,
as I wouldn't feel safe being so close to the blade, especially on something lightweight which could move about.
Probably wouldn't be so mobile thereafter, but would likely be safer.

 

[Agent_zed]

There's also option to make a positive stop for a sled.
Seen some ideas on YT before, but they don't appear trustworthy atall,
but the idea is there for someone who might be of the opinion that their fingers are more important
than the work, and it's up to them to make things safe, and not just for this week.

i.e, cleats and screws used for something which gets bumped, are likely to come loose sometime.

If I had one of those little ripping machines, I'd be welding up a hefty metal cage around it of sorts,
and I could hang infeeds and outfeeds from it, and whatever else needed,
as I wouldn't feel safe being so close to the blade, especially on something lightweight which could move about.
Probably wouldn't be so mobile thereafter, but would likely be safer.

But would you use something like this UJK Precision Mitre Gauge Fence & Flip Stop ?

I am not currently understanding the difference. A sled is just 2 of the above working together? which is surely safer as it is supported by 2 rails rather than the just the one side.