How to make riving knife for Delta 36-725 table saw

[@timromano7085]

But shouldn't the riving knife be a little *thicker* than the blade (yet narrower than the kerf) to prevent the board from pinching the spinning blade?

[@namoothewoodprojects]

I think that’s the ideal! But so far it works fine with me. No kick backs yet luckily

[@w9jim]

This should be thinner than the saw cut since it's using just the blade. The teeth on the cutting blade will make the cut wider than the knife.

[@grumblycurmudgeon]

No! You absolutely do NOT water the riving knife THICKER than the blade! It should be a butterfly's eyelash THINNER. This is why you can get away with a thin kerf knife with a full kerf blade, but not the other way around. Think about it: the purpose of a riving knife is to prevent the any stresses that may be present in the workpiece from causing it to clamp down on the blade, after it's passed through it (since that has a tendency to, yanno, either damage your saw's motor, or to turn it into a rapidly-expanding cloud of relativistic splinters). Instead, it clamps down on the riving knife (which is a smooth, low friction surface with nothing to impede the workpiece being pushed through). You want something EVER so slightly THINNER than the blade. We're talking for a think kerf blade (3/32", or 0.09375") you want a 0.09" riving knife (a difference of 0.00375", or about a tenth of a mm), which by the happiest of coincidences, happens to be the precise thickness of 13ga steel. This is to ensure that its wide enough to ensure if the workpiece DOES clamp down, the sheer speed of the blade will BURN (if nothing else) enough breathing space to prevent a bind, but will not impede the ability for the workpiece to push through. Same goes for full-kerf (1/8" or 0.125"): you wanna riving knife of ~0.12" (which, hey lookie there: matches 11ga steel precisely). Were it WIDER than the kerf: you would now be trying to shove the let's call it 3/32" slot you just cut into the piece around a let's say 7/64" obstruction. At best, damn near every cut you'll ker-thunk into the knife and stop, causing burning and chatter. If it's a soft wood, you can likely shove it through, but you'll get crap cut quality (and bend your knife, eventually). If it's HARDwood, that you've just reduced the EXIT PATH BETWEEN THE SPINNING BLADE AND THE FENCE BY 1/128" on, it's gonna fight getting compressed. So, you're going to push harder. And you know what makes for a REALLY bad combination of circumstances...? The reason namoothe's hack works is because he has a blade that's the SAME thickness as the manufactured knife, and has a saw with a knife that's perfectly in-line with the blade, a feat achieved by (and I have a 36-5000, so I know of whence I speak here) dumb luck. Some of them are spot on, some are off by a thou or two. If you replicate this, after shaping the knife, sand all the writing off. Go up to 320, at least (I'd go prolly 1000; you want NO friction if possible). That should be enough to reduce the thickness that eyelash, improving safety without impairing performance. Adding a tiny bevel to the leading edge with a round file wouldn't hurt, but generally the knife is so close to the lee of the blade it's academic.

[@bryanlaurie8129]

Please use some sort of clamp, especially when driling thin steel items. When the drill grabs and turns your part into revolving knife you won't have any fingers left for the saw to remove.

[@ManOnPryor]

Yep. Can’t find one anywhere. Don’t know how I lost mine.

[@namoothewoodprojects]

Time to make one 👍

[@petermead7510]

Is there a copy of that somewhere i can use to print one out?

[@namoothewoodprojects]

Unfortunately I do not.. I looked up on google that has grid background so when i print out i can measure its the actual size. I had to adjust size couple times and print out couple times. Sorry i couldn't help you

[@D13MA]

Where did you find the cut out sheet for this riving knife?

[@namoothewoodprojects]

I forgot which website but I googled it. I believe it was an online tool shop where sells them.

[@xuthnet]

Of course, had I been thinking, I would have quickly found a better quality image: fixcom.azureedge.net//assets/partimages/10332203_1_L.jpg (but this one hasn't been appropriately sized yet)

[@zachc1]

Thanks for this

[@grumblycurmudgeon]

What would it take for to convince you to send me that template!? I lost my riving knife when we moved shops, and NOBODY has them in stock!

[@namoothewoodprojects]

I wish I could.... this video was made about 2 years ago and I don't have it anymore..!!!! I know, NOBODY has them in stock. It's weird bc this table saw is pretty popular