Thread: Causes of Kickback while ripping

If you fence isn't parallel to the blade(in at the end of the rip) it will bind and not be able to pushed through. If you then ease off on the pressure you are applying to your workpiece then it can kick back. I had a discussion about this at the Open Day I worked at on Sunday, someone asked me if I had seen an "anti-kick back blade" and was told that this blade would prevent kick back. I wouldn't like to try it though.
Woody

Some blades are less prone to kick back than others dues to the design, also the rake on the blade should be correct for the type of saw, ie: don't use a tablesaw blade in a SCMS, that is asking for trouble.
I also believe that kick back is a result of the surface of the blade pushing everything back and the teeth at the front trying to lift a piece that is offset.
Are you sure someone wasn't talking about anti kick back pawls, the teeth on those little jaws in front of the blade attached to the riving knife?

In my experience, you're right in that they can be causes for kickback.

I know timber closing on the blade can! Been there, done that, recommend a riving knife when ripping to all'n'sundry. Should start doing it myself one day.

As for the non-parallel fence I think it depends. Too much difference and the blade binds, but I have caught myself having brain-dead moments where I've set the fence with a 1cm difference. Worse, I use a thin-klerf blade which has enough flex that it doesn't bind with that much offset. Last time it wasn't until I'd fought half-way through a 6' rip and the timber started lifting beyond my control that I hit the big red button. Like I said: a brain-dead moment. [sigh]

IMHO, if there had been a hard knot or something, just enough for the back of the blade to make a good catch instead of back-cutting, it would have launched it in an almighty kickback.

Some folks have their fence set permanently off parallel, ie 1mm or so further away from the blade at the far end of the fence.

Skew ChiDAMN

Thanks, that is what I was after.

I didn't want to spend ages in a timber yard looking for timber that would be likely to close on the blade so I could demonstrate.

As for the thin kerf blade, is this for a faster rip or to cut back on wastage?

I am forever trying to explain the need for the thicker blade because of the riving knife width and also the lack of sideways play.

Due to the Japanese hand saws being pull saws, people here expect all blades to be razor thin.

Appreciate your answer. I have been too stingy with my greenies and they won't let me give you another at the moment.

Steve

Steve, I use the thin-kerf blade solely to reduce wastage. For economy reasons I often rip 90x45mm pine studs into 40x20 carcase battens and need a mm or two leeway for dressing.

When wastage is not an issue, IMHO there is no excuse to not use a std. blade and knife for ripping. A thin-kerf blade doesn't cut so much faster that it's worth taking risks.

I have noticed that Sappy timber will kick back more so than completely dry timber stock with any blade at my disposal, but I do not have the answer.

Regards Mike.

Those 3 factors can all cause kickback.

another cause is the operator allowing the leading edge of the timber to be off the benchtop (most likely if cutting a long piece of timber that isnt supported over its full length)