KICKING BACK -- not in a good way

were you cutting with the grain or against? Why use a sled? why not directly on table top? I’m not sure I understand your process..I think your piece might have tipped on the sled, the blade grabbed it and whammo…a thought..I don’t understand the sled & incra positioner in combo…

Mary Anne, From your description, I really don’t see anything wrong with your method.
I am scrathing my head wondering what might have happened. Maybe if you could post pictures of the process someone might offer some help.

Sometimes on smaller pieces, clamping to the sled is a wise choice. I do this all the time.

-- http://shepherdtoolandsupply.com/

Another thought for the future..
I would have chosen a router in a table..and the piece directly on the table…

Mary, I’m glad it wasn’t any worse than it was. Hope you heal quickly. I can’t quite picture what you were doing. I would be interested in a picture of your setup if you have the chance.

It almost sounds like you were ripping the pieces using your TS sled. Unless you have proper blocks set in place that sounds like a problem. Unfortunately, I’m not sure I understood your description. I’m sure I have it wrong.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

One thing that might have caused the blowing apart you described is the wood itself. Hickory is a very hard wood and with hardness you usually get brittleness. Since the side pieces were so thin, you likely got a lot of vibration in the wood (like when cutting a thin piece of plywood).

If that is what caused the problem, you might try clamping a support block made of some softer wood on top of the hickory side piece on your sled. This would allow the vibration to dissipate.

I hope you get to feeling better soon.

I would second the thought of putting in directly on the saw table instead of a sled. You can put pressure over a larger area and the wood would be supported more over the whole piece. I would think it would be hard to put enough pressure over the whole piece on a sled.

The Gripper Ripper would be a good tool to use in an operation like this.

Domer

AAuuch !!
hope you recover fast Mary Anne

take care
Dennis

Thanks for your responses and concerns. I appreciate it! I am fine now but for the last little scab.

To clarify: The Incra Positioner had nothing to do with cutting the dado; I only used it to cut the box joints on the router table. Sorry for the confusing extraneous info.

I was, however, using an Incra Miter Express sled with a Miter1000SE which is a rock solid, zero clearance setup that rides tight in the saw’s (Grizzly G0690) miter slots, no room for wiggle, tipping, or drop off. This setup, at the time, seemed like a good idea for putting a shallow dado in small, thin stock.

Kent, I think you are on track that I should have also clamped the piece to the sled. As secure as I thought everything was, something must have moved. The strange things was that it happened the instant I touched the workpiece to the blade; it just grabbed and blew up.

Dustin, the vibration of the thin wood and the brittleness of hickory also sound like major contributors to what happened. That is something I had not thought of in the last month of second guessing myself.

As for the “coulda, shoulda, why not this way or that?”... as I said, I know there are other ways. When I re-did the project, I dadoed the whole board up against the TS fence before cutting it down into the individual sides. That is my normal practice, but the dado was a design change. I probably would have used the router table for its easier, quicker setup, but I do not have an 1/8” bit. Yep, using the Grrripper would have been another excellent alternative that I could have used with less likelihood of kickback.

What I am asking is if there is something inherently inappropriate or dangerous in using a sled in this way?

I’m sure this could be safe, but I still wonder why you used a sled..direct on table..you are not cutting up thru the piece of wood, so it’s safe to use a pusher of some sort, directly over the piece. One of my rules in the shop is use the smallest blade/bit presentation I can..a 1/4 or 1/8 th bit leaves very little metal above the table top..a dado blade is lots more surface area to catch anything.(was the dado dull? any bad teeth?) Was there a knot? Is your sled on both sides of the blade? no dropping onto the table after cutting? I believe you had a vibration/slippage problem and you had an accident..glad you are ok…If you insist on using a sled for these operations you need to get your clamp right up close to the cut line..as close as you can..keep the vibration down when the dado hits the wood. Or 2 clamps..

michelle
I don’t insist on using the sled for these operations—it is just what I chose to use at that time, and I want to learn from the experience. While I consider myself a rookie at “fine” woodworking, I have owned and operated table saws and every other kind of power tools for nearly 40 years (eek) without incident. When something does happen, I go over it in my head until I ‘get’ what happened. When I understand, it is from there I may or may not use the same method in the future.

No dado blade; it was a sharp, nearly new high end Freud combo blade… can’t remember the exact model. No knots, no drop off. Yes, the sled covers both sides—zero clearance. I believe Dustin got it with the vibration and brittleness issues. And clamps might/probably would have prevented it.

With small stock I personally think it’s dangerous not to use a push block that covers the cut (or holds both sides in the case of a through cut – with a Gripper for instance). I think you could have had the same sort of “explosion” happen on a router or with the table alone. I know a lot of people don’t use them, but they make me feel better.

As to the cause, I’m with Kent. I had a thin piece splinter like that on me once. It was LOUD!! Scared the out of me, but fortunately no injury except to the workpiece.

That’s my two cents.
Sorry you had the accident, but glad to hear you’re okay.

-- Kate, http://www.wooden-box-maker.com

MA .
even with your new explanation
i too have trouble understanding what you were doing .

i am how ever glad that you made it thru this without to much injury .

as i know nothing of the incra tools you used ,
i can’t imagine what you are talking about .
please show us pictures of a mock up as it was happening .
we can understand what happened better
you will be safer ,

and maybe someone else will be too in the future .

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

Thanks, Kate. The annoying thing is that I had a Grrripper hanging on the wall right next to my saw and it is what I usually grab when I am doing the same thing on longer pieces, but for some reason, the sled made sense at the time for the smaller stock. Oops. :/

patron,
It’s dinner time now, David, but I’ll go down and take a photo after… if I don’t fall asleep first.

The whole thing is worthwhile if it prevents someone else from having the same thing, or worse, happen.

The important thing is that you’re ok.

-- Dale West Central Pa. Do it all, before last call.

Mary Anne, sometimes it isn’t what you did. Wood will “explode” sitting on your bench. I may be as simple as that piece of wood was “ripe” and you simply couldn’t have known or done anything to prevent it.

-- .