Kickback

[everettdavis]

I put this in Maintenance because Maintenance and adjustment is the area where mitigation of kick back will occur as you adjust existing equipment or install safety gear. Obviously proper operation is essential as well.

Kickback on a saw is dangerous we all likely agree we need to take steps to avoid it.

There are very good well known practices and safety equipment to mitigate kickback.

Beyond the obvious of The kicked back piece of would striking you, one would do well to envision the piece of wood you are pushing into the blade suddenly disappearing from your hands and your inertia taking your hands directly into the blade.
Blade Guards, push sticks, anti kickback pawls, riving knives, board buddies, JessEm stock guides, fingerboards and other safety devices are available, but have to be on the saw and adjusted properly to protect you.

“I’m just making this one cut” so I’m not using the safety gear likely is cause for many trips to emergency rooms.

I have said many times, I don’t know any safety gear that is more expensive than one trip to the ER even if you come back with all your fingers and recover full use of your hands.

Let’s look at the mechanics of kickback velocity.

Consider a 10” table saw blade which has a 31.41” circumference. That’s how far it would travel in a straight line rotated 1 time.

The saw blade turns 3450 RPM

3450 / 60 seconds = 57.5

57.5 Revolutions per second times 31.41” blade circumference yields:
1806.075 inches per second or 150.5 feet per second.

That’s just over 102 miles per hour, instantly heading toward you, from mere inches away from your head.

You can’t react that fast, and worse the kickback has a random trajectory so even if you could begin to move, you might still move into its path.

Learn what causes kickback and learn how to mitigate it on whatever saw, router, shaper, or jointer you use.

Learn about woodgrain and what Climb Cutting is on a router table which occurs when you feed the stock from the opposite side than right to left. It can create a projectile away from you but towards someone else or ricochet and still hit you.

No I am not going to tell you what causes it and how to remedy it in this document.

I am just warning you that you need to study your equipment and learn what causes it and how to avoid it hurting you or someone or even some thing you love like that classic corvette in the driveway.

Here is a video link to get you started on your journey.

I just picked a random one.

There are numerous ones out there and it does not have to be a short piece of stock as illustrated.

Everett

https://youtu.be/ZUZ8hRm7a8g

[JNewton]

Thanks for a timely reminder. I for one have never used a table saw before, and need to study up on this. I did order the insert for the table so now the saw cover/guard should be useable. Do I get safety points? I think that’s what gets accrued and then all used up that one time “it could have been real bad.”

[RFGuy]

Thanks Everett. Good advice as always. I had seen this kickback speed info before, but I think it bears repeating. So, I appreciate you doing the math and sharing your thoughts on kickback here. I have only had it happen once or twice to me in all of my woodworking, but I can tell you I don't EVER want it to happen to me again. Getting even a small cutoff slung back at you hitting you in the stomach or chest is definitely no fun and can be deadly. I am certainly much more careful now, but I also better understand what causes kickback than I did when I was younger. Maybe I sound like a Jessem commercial by now, but I don't work for them...just really happy with their product. Below is the thread where I talked about installing the Jessem Clear-Cut TS™ Stock Guides on my Shopsmith 520 fence. I feel a lot more confident ripping now using it, but that doesn't mean I am not careful while using it. It is an expensive indulgence though, so if someone doesn't like them or can't afford them, then I highly recommend they always use a riving knife and make sure their rip fence alignment is adjusted so that the stock isn't pinched near the back of the blade as a minimum.

https://www.shopsmith.com/ss_forum/wood ... ml#p255807

[wa2crk]

Everett
Couple of years ago I also computed the velocity of a piece of stock coming off the saw blade during a kickback situation and came to the same conclusion. There other things that can cause kickback when using a table saw. I very often see some of our woodworking club members mark a piece of plywood to make a rip cut and they put a mark on the face and when they start the cut and they see their mark drifting away from the the blade they try to to get back to the line by twisting the stock. FATAL ERROR!!! That will cause the piece to kick back. When I train a new member on the table saw I install the upper saw guide and cover the guide with masking tape. The complaint I usually get is "I can't see my cut line". You don't have to is my reply. You should watch where the stock rides along the fence because the table saw is for straight line cuts. Then they respond with something like "Oh yeah you're right". I also found out that you really can't teach an old dog new tricks. Enough rant.
Bill V