Want to make rebates on table saw (riving knife in the way)

[Gary_S]

Hi, as per the title. I want to cut rebates / rabbets (depending on your side of the Ocean). I know I can route them but my router table is in need of repair, too many for a hand router and I am stubborn and want to use the tool I envisaged using. However, Newtonian physics means that I can't have the wood and the riving knife in the same place. I won't remove the riving knife for obvious reasons so how do you guys overcome this? Sacrificial block the same height as my riving knife was my only thought and that isn't the best I'm sure.

Gary

 

[heimlaga]

I won't remove the riving knife for obvious reasons so how do you guys overcome this?

An overarm guard made from scrap yard materials and a riving knife that doesn't protrude above the blade.

 

[Jacob]

Overhead guards not a good idea unless really heavily engineered - if they catch the blade all hell breaks loose! And they don't tilt with the blade. In any case they don't protect you from anything if the blade is in the wood cutting a slot to start with.
I'd cut rebates without the riving knife. Just needs sharp rip blade, a bit of care and preparation and TWO PUSH STICKS.

 

[Zeddedhed]

Overhead guards not a good idea unless really heavily engineered - if they catch the blade all hell breaks loose! And they don't tilt with the blade. In any case they don't protect you from anything if the blade is in the wood cutting a slot to start with.
I'd cut rebates without the riving knife. Just needs sharp rip blade, a bit of care and preparation and TWO PUSH STICKS.

+1

 

[deema]

Avoid the table saw, it's not designed for this type of operation. Doing this type of thing is a good way to discover the powerful energy of a kick back. Push sticks help stop you loosing bits of your hands, and real good kick back can cause the wood to penetrate vital parts of the body.

Either wait for your router to be fixed of better still, use a rebate plane. As long as your not cutting 10's of linear feet it will faster, more controlled and produce a neat finished surface.

 

[rannndy]

nothing wrong with cutting rebates on a circular saw been doing it for 50 years with and without riving knife. all you need to do is stay focust
john

 

[Jacob]

Avoid the table saw, it's not designed for this type of operation. Doing this type of thing is a good way to discover the powerful energy of a kick back. Push sticks help stop you loosing bits of your hands, and real good kick back can cause the wood to penetrate vital parts of the body.
.....

Dunno I've never read of a bad one happening through kick-back except with big machines and heavy timbers; there is a limit to what can be done hand-fed. Not that it doesn't happen of course but a lot of it seems to be apocryphal. There is a a very simple safety measure anyway - don't stand in the firing line.

On the other hand there are dozens of photos of bleeding stumps, nasty cuts, etc all down to being too near the blade (obviously!)

 

[Sgian Dubh]

As others have indicated, using a saw for this task is perfectly possible, but somewhat frowned upon from a UK regulations point of view, unless you can provide alternative guarding to keep fingers away from the blade, and to prevent kickback. A simple solution that adds a good measure of safety would be to cut a piece of 6 mm plywood or MDF to fit on the face of the rip fence. This is a sacrificial piece to prevent the sawblade damaging the fence later.

Next, drop the blade below the table, place a piece of your wood to be rebated against the sacrificial piece/ saw rip fence and simply clamp a piece of straight edged wood to the fence with its bottom edge set on top of the project piece. The hold down covers the blade and holds the working piece down. Perhaps even better would be to cut fingers in the edge of the hold down that add extra pressure through pressing down as you apply the clamps to lock the hold down to the fence - plywood would be a good choice for both types of hold down. If the riving knife sits above the blade, you'll have to remove it temporarily. And if the rip fence locks only at the infeed end, you may also need to clamp the outfeed end down to prevent any chance of the fence/hold down arrangement lifting in use.

Set the sawblade to the correct height and take out the rebate in a series of steps through moving the rip fence as needed, and use push sticks to add a further margin of safety. Slainte.

 

[mikefab]

I've done this on the saw using two cuts rotating in between (15x35mm rebate for sashes). I used some of the magswitch hold downs and feather boards to guard the cut. I tried using the router table as per accepted best practice but got bored as 4 passes were needed for a clean cut and I had about 30 components to do.

 

[Jacob]

..... I tried using the router table as per accepted best practice but......

Nothing "best practice" about using a router for a job much too big for it (not to mention the noise and the dust!).
Best would be a spindle moulder

 

[mikefab]

Err yup but obviously I don't have one of those.

 

[mikefab]

Err yup but obviously I don't have one of those.

Although of course you are correct!

 

[Jacob]

Err yup but obviously I don't have one of those.

Although of course you are correct!

And your saw set up is better than using a router IMHO.
A bit OTT on the protection perhaps? Too many bits n bobs can get in the way of the push stick and defeat the object.
Personally for a repeated small rebate I'd have just the one feather board perhaps. AND TWO PUSH STICKS.
It means you can poke the workpiece in quite casually with little risk of it going astray.
One "safety" thing to avoid is the gripper. They are seriously stupid - you have to reach past the blade to hold down the workpiece so they shorten your reach. Push sticks lengthen it. Grippers also have your arm over the exposed blade as you pass through. I think they should be banned.

many variations on this theme:

 

[deema]

I fully agree with Jacob about the gripper, there is on uTube a 'lovely' clip of a seriously demented chap creating a kick back on a saw and nearly loosing his fingers doing it. The power and speed of a kick back cannot be controlled and anything that causes your hands to go close to the teeth could be seriously unhealthy.

Looking at the picture of the saw setup for the rebate cut IMO you should never have a fence that supports the stuff beyond the gullet of the leading teeth. This is normally achieved on such a fence by having a sacrificial wooden fence attached at the righ length. However, the saw looks to have a fence that can be pulled back / adjusted to the size of the blade. The reason is that if the fence pinches in towards the blade at all (older quality saws not have a fence than cants c1~2 degrees away from the blade) it is highly likely to cause a kick back

 

[mikefab]

No Grippers here!

You will see to the right of the saw there is a long thin scrap of timber. I was using this to poke the workpiece through the 'tunnnel'.

OTT on the safety? Maybe, but I wanted the workpiece held down and in to the fence as if there were a Shaw guard there. The guard stays in place permanently as per previous discussions but doesn't really form part of this set up. Making the cuts felt like a controlled operation to me but I am quite new to working with machines.

Interesting point about the fence position deema. Yes it is possible to reposition the extrusion and I usually have it correctly positioned as you described for ripping. I can't quite remember why but I deliberately placed it as I did for this cut.... perhaps the theory was that as I was doing a non through cut it was better that the workpiece remained aligned with the axis of the cut rather than having the option of twisting out of line. There shouldn't be a risk of the kerf pinching closed over the saw in this situation?

And by the way, I set the second cut up so that the waste piece was on the outside away from the fence to avoid it being hurled backwards.

Always interesting to hear what other people have to say about the way I do things. .. it's a good way to learn! I know that a spindle would be the machine of choice but as that is not an option I need to find the next safest most convenient way to do what I need to do


Cheers
Mike

 

[Paddy Roxburgh]

If you remove the riving knife be absolutely sure to think about where the wood would go if it kicked back, stand to the side (as you should with all TS cuts). Jacob's dead right about 2 push sticks. One can push the work and the other hold it down, doing the job of both feather boards in Mikes picture. Personally I've never used feather boards on a TS, probably a good method though.
Paddy

 

[Dan j]

How big a rebate are you cutting and what wood?
Kick back isn't usually much of an issue with smaller rebates as the remaining timber normally holds the saw kerf open wide enough for it to not catch on the blade.

 

[Jacob]

....... Personally I've never used feather boards on a TS, probably a good method though.
Paddy

I've used them when doing a repetitive run. That's when you lose concentration but a feather board will hold the workpiece in place even if you let go of it . Or with a long piece where you have to change holding position as it goes through.