Similar to When is it not possible or not practical to use a blade guard?, what types of cuts require the riving knife (and blade guard) to be removed?
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2 Answers
Although there are many instances in which you need to remove a standard or modular table saw blade guard, most cuts can be made with a riving knife installed. However, there are a few operations for which you must (or should) remove the riving knife:
- Raising the blade through a workpiece (e.g., when cutting the slot for a crosscut sled or zero-clearance insert)
- Using a dado stack (the riving knife does not perform its duty and, in fact, will probably block your workpiece; for example, if installing an 8" or 6" dado stack along with a riving knife intended for a 10" blade)
- Cutting coves
Also keep in mind that your riving knife must be approximately the same thickness as your blade. If you use a standard-kerf riving knife with a thin-kerf blade, your workpiece may be blocked by the riving knife or may pinch it, or may be pinched between the riving knife and fence. Conversely, if you use a thin-kerf riving knife with a standard-kerf blade, your riving knife will not be as effective at preventing kickback.
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I think I've seen riving knives that aren't stuck at a fixed height; they are spring loaded and can be pushed down. So maybe you could manage #1 with the riving knife in place.– larsCommented May 5, 2015 at 22:12
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1@lars That would be handy as long as it's safe to use in that manner. I haven't seen a riving knife like that, but I wonder if you're supposed to allow it to retract during saw operation or only while making adjustments with the saw off. You'd have to make sure it retracts in an arc, even with direct downward for applied, to avoid hitting the blade. If you do happen to run across it again, please share the link.– rob ♦Commented May 5, 2015 at 23:08
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1I'dbe interested in that link too. I suspect what you saw was just that the riving knife moves up and down, and tilts, with the blade -- unlike a fixed splitter.– keshlamCommented May 5, 2015 at 23:47
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Googling a little, I did find a Bosch riving knife patent that seems to describe a retractable riving knife, but at a glance it appears that the riving knife is intended to be set at a fixed height via a wingnut or thumbscrew, and is not supposed to retract during saw operation. It also may not have been spring-loaded.– rob ♦Commented May 5, 2015 at 23:56
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1@Ethan48 Why on earth would you need to climb cut on a table saw? I've never heard of such a technique being used. That sounds like a great way to get your hands pulled straight into the blade.– DoresoomCommented Jun 30, 2015 at 16:13
The riving knife on my table saw (Powermatic 2000) extends higher than the blade. This is because it also functions as the mount for the blade guard which I no longer use since I have come to appreciate the safety factor of the riving knife.
It is necessary to remove the riving knife whenever I make any cut that is not a through cut, i.e. a groove. I have frequently thought, though not acted yet, to hacking off the riving knife so that its top is even with the top of the blade.
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That's interesting; I've seen that riving knife/guard and thought it was really slick, but I had assumed the riving knife part only went as high as the blade.– rob ♦Commented Jul 14, 2015 at 23:46
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Before you do that, make sure there isn't a way to adjust it lower. My Ridgid R4512 riving knife sounds to be very similar, and it's got a secondary position that lowers it below the top of the blade for non-through cuts.– DoresoomCommented Apr 13, 2016 at 16:10