I recently had a reminder of how important using push blocks can be. I was routing a 1″ slot in in the center of a piece of plywood with a 3/4″ bit. I formed the slot by running the piece though the bit from right to left with one side against the fence. Then I turned the piece around and routed the other side (also from right to left).
By running this second operation from right to left, I was technically performing a climb cut, because the back of the bit was doing most of the cutting. Climb cuts are when you move the wood in the direction the bit is turning instead of against it. They can be dangerous, because you have less control and the wood can be flung from your hands.
It doesn’t always happen, you can perform a climb cut without incident many times, but the potential for an accident is higher. Five years ago I was performing a similar climb cut when the bit caught the board and sent it flying. That time I wasn’t using a push block and it was my finger that went into the spinning bit. After that $800 trip to the emergency room to sew my finger back together, I’ve been using push blocks.
This time the bit caught and threw the board I was routing across the shop. The push block did its job and went into the bit instead of my hand. Even though I wasn’t injured my heart still pounded for quite a while after the incident.
That night I purchased a Grr-Ripper that Stuart reviewed and recommended, and I plan to use it to compliment my damaged push block. I took advantage of a recent MicroJig deal, where I ordered the basic Grr-Ripper and received a free upgrade to the advanced Grr-Ripper push block.
If you don’t need the fancy features of the Grr-Ripper, you can buy an also-strongly-recommended Bench Dog push block for $10 via Amazon. You can find basic push blocks for less.
Push blocks aren’t going always going to prevent injury, but they put more material between you and spinning cutters or blades, and they give you more control over the workpiece. They definitely aren’t an excuse to get sloppy in the shop, but they are one more line of protection when something unexpected happens.
Have you ever had an incident where a push block saved the day? Or perhaps one where a push block would have saved the day?
So true. Not just on the router, but any other tool where you’re hands pass near the cutter. Jointers in particular.
Yes, yes, a million times yes. You never think that kickback on a table saw or the climb-cut rail gun effect is terribly dangerous until it happens. Use featherboards, use your blade/bit guards, and use pushblocks. They’re too cheap and too easy.
Or, we can just survey the audience: raise your prosthetic hand if you think that power tool safety isn’t manly!!
I’ll raise my real hand. This sounds like a testimonial to using tools properly.
Or you could just recognize that safety devices still help prevent injury even when using tools properly since things still happen, especially in wood, a material that changes as its being cut. You don’t have to try and show us how manly you are
But how else will you know?
Koko the Talking Ape
Hoo, scary! I’m glad you are alright, Benjamin.
You made two passes because you wanted a slot wider than the router bit. You did one pass in one direction that cut one side of the slot. Then you did the second pass in the same direction for the other side, but that was a climbing cut.
Could you have made the second pass in the opposite direction as the first, and so avoid a climbing cut?
Yes, if I had been thinking about it, I could have made the second pass in the other direction.
The first two slots didn’t have any issues, the next one slipped a bit and I thought, “hmm I must be climb cutting, I’ll complete the cut and then I’ll set the cut up for the other direction.” Then it shot out from under me.
I stopped after that and haven’t gone back yet to cut the remaining pieces — not because of the push block incident, but because I started some other projects.
Koko The Talking Ape
Sure. I brought it up because I think I read in the Router Handbook (or something like that) that you should visualize that kind of cut as a long narrow rectangle (as if you are routing the inside of a long box) and you want to go clockwise (or counterclockwise) around the entire inside of the rectangle. That would mean one long side of the cut is made in one direction, and the opposite side is done in the opposite direction.
I guess another way to think about it is that you should always be fighting the blade’s rotation. The blade should always rotating against the feed direction, cutting up towards the surface (where it will likely cause some tear-out), not biting down into the surface.
If it helps anyone, this is a handy guide from Lee Valley that I still look at once in a while.
Best of luck with the projects!
I was cutting a slot in a leg for a plywood backing on the table saw so no guard was being used. The blade caught the leg and flung it away from my hand which proceeded to go down on the blade. Luckily it was just four stitches on my thumb and not replanting the thumb onto my hand. Wished I’d used a push block and featherboard.
My rule is that if my hand needs to be within a “hand’s-width” of the blade – then its time for a push stick/push block. Crosscutting is perhaps less dangerous because I’m usually using a miter-gauge or sled (my Unisaw has a sliding table) – but ripping or even cutting slots and dados is riskier. As you say – featherboards can also help hold the work into the fence – but with natural wood’s sometimes internal stresses – binding and a kickback can result anyway. For some cuts using an auxiliary L-Fence also makes things safer.
There are times I wish I had the space in my home shop for a dedicated rip saw – like the Oliver machine we had in the cabinet shop – with a dedicated work feeder. There are other times when I’ve thought of replacing my nearly 50 year old Unisaw with a Sawstop or a more modern European saw (like a Hammer) that has a riving knife.