changing my riving knife

[skeetstar]

Fellas, am now getting used to my Axi 10 in table saw, but I was wondering if I would be wise in making some changes;

The riving knife is taller than the blade, and the knife also serves as the mount for the blade guard. This means that I couldn't use the saw to cut rebates or housing joints. I could cut the knife down so that its top sits a fraction below the top edge of the blade. I would have to cut a new slot in the knife to support the blade guard, so that the guard can be reinstalled for normal use.

To be honest I probably won't do it - I'll leave it as it was designed, but would any of you more experienced users ever contemplate such a course of action? Are there some major gotchas that I haven't spotted? Would it still be possible to cut a rebate with the reshaped knife in situ?

Secondly, when I change the existing blade for something better, do I need to check the new blade to ensure that it is OK with my existing riving knife, or should that just be a given?

Thanks in anticipation.

 

[focusonwood]

I've got the same issue with my Axminster saw.

I was contemplating making a new one or getting one fabricated.

 

[slemishwoodcrafts]

If you cut the riving knife to be lower than the blade this would be an ideal time to build an over arm guard for your saw which I found improved visibility and dust extraction


Sent from my iPhone using Tapatalk

 

[woodbrains]

Hello,

You must leave a riving knife on the saw, no matter what you are cutting. Removing it completely is a big no no.
If you cut the existing riving knife to just below the level of the saw blade tip, then you can perform partial thickness cuts, but have no guard mounting point. If you file a new slot to take the guard, for normal sawing, then you limit the depth of cut on the saw and you limit the fall on the blade. In other words you have to have the blade too high for cutting thinner stock. I would not recommend this; the ideal for safety and efficiency is having the tooth gullets set just higher than the material thickness. The guard in a cut down riving knife prevents this. You could make a short knife, and swap from one to the other as the job demanded. The plate thickness would have to be correct, though, there is a fine tolerance on this, for the knife to actually function correctly. And how consistent would you be changing the knife every time? If it is fiddly, it is likely to just get left off, which is not good. The only viable option is to make an overhead guard on a boom of some sort. For a portable saw, this might not be convenient, it depends on your set up. If the saw does not move about in your workshop, it might be the way to go, if you fancy the fabrication job.

However, I would advise using a router table for rebating and leaving the saw as it is. A router table is safer than partial ripping, and will have so many more uses for so many things. I'm assuming you don't have one. Even a small spindle moulder I find safer, more accurate and easier to set up, than rebating on the tablesaw.

Mike.

 

[MattRoberts]

Hi, I cut the riving knife in my aw10 with a jig saw just fine. But as stated, I chose not to use the blade guard (I can hear the gasps!).

It's dead easy to do, but of course you do so at your own risk!

 

[SPSlick]

I simply bought a second riving knife and cut it down so I can swap between the two on my AW12, can't remember the exact price but it was pretty cheap.

 

[woodbrains]

Hello,

Just a word about blade sutability for the riving knife fitted. It should not be taken as a given that a new blade will be suitable. The riving knife must be a smidgen thinner than the kerf, but a smidgen thicker thane the saw plate. If your saw was fitted as standard with a 3.2 mm kerf sawblade then buy one with the same kerf. There are many thin kerf blades about that will not work in this case, unless you get a knife to match, otherwise it will bind. If your saw is fitted as standard with a thin kerf blade, then do not use a regular kerf one as the riving knife will not hold the cut open as it should, if the wood should close up behind the blade.

Mike.

 

[heimlaga]

A low riving knife in combination with an overarm guard has been industrial standard for cirkular saw benches in most of Europe for the last 50 years or so. With this setup it is perfectly acceptable to make various threnching cuts both along and across the grain.

Only lately high riving knives with the guard mounted on top have had a breakthrough. Not because they would be superrior in any way but because they are cheaper to manufacture and can be packed more compact on the ship from China.

I have made low riving knives and overarm guards for two of my cirkular saw benches. My site saw was fitted out like this from factory. A safety feature that never has to be removed in use is most likely to be in place and do it's job when an accident strikes.

The saw on my combination machine is in regular use since several years:

The big rip saw with 24" blade isn't yet in use awaiting some electrical work and a bit of paint:

 

[Eric The Viking]

I simply bought a second riving knife and cut it down so I can swap between the two on my AW12, can't remember the exact price but it was pretty cheap.

They are indeed pretty cheap, and available for the TS 200 -- I think a fiver (or not much more).

I bought several last time, so I could experiment.

E.

 

[skeetstar]

Woodbrains:

'If you file a new slot to take the guard, for normal sawing, then you limit the depth of cut on the saw and you limit the fall on the blade'.

That is a very good point, one that hadn't occurred to me. Looks like if I decide to do this in the future, an overarm guard will need fabrication, per Heimlaga's suggestion. Think I will leave well enough alone for now, and maybe look at ta routed table..

Thanks all for input, really appreciated

 

[geoffshep]

There's a good video on here on the reasons why removing the riving knife is a bad idea. great-video-on-the-importance-of-roving-knife-on-your-ts-t101522.html

I took a bit off the top of mine (leaving the notch for the dust guard) but also extended the slots at the bottom (at the top of each slot) so that the knife could be pushed further down.

I also opened out the bottoms of the slots so that I can remove it without having to completely remove the arbour nut - which I had previously managed to drop down into the dust extraction tube. The intention is not to run the saw without a knife but to be able to change knives easily so that I can switch between tall and short knives.

 

[Steve Maskery]

I also opened out the bottoms of the slots so that I can remove it without having to completely remove the arbour nut - which I had previously managed to drop down into the dust extraction tube.

I feel obliged to point out that that is not recommended. Yes it makes changing the RK easier, but the bottom end is closed off for a reason. If it becomes loose and makes contact with the blade, it can get thrown up at you like a spear. The closed end means that it is retained on the saw
A better solution would be to cut an open slot in the front, between the two ends of the existing slot. You could then just hook it over the fixing bolts but the bottom end would still be closed.

 

[sploo]

Not at home at the moment so I can't post any photos.

I have the TS200, so got a spare knife which I ground (the top) to be just under 1mm below the very top of the blade, then drilled another hole for the guard. I can then use the guard (pretty much as normal - just with a slightly reduced max cutting height).

Removing the guard allows the use of a crosscutting sled, and cuts over the top of the blade (not that I particularly like doing the latter) - it's what a router table is for.

 

[Copes]

I also bought a second knife as i didn't want to potentially wreck my original one, i think they were £3.80 or something from axi for the AW10.