This is what can happen when you stop thinking for just one second —– then you realize what a very stupid move you made and where very lucky that you where not standing behind the bade where I normally stand this one time. STUPID -STUPID-STUPID–The arrow is actually a 1/4″ square by 36″ long piece of beadboard that I was rushing to cut off a small sheet. The piece flew 10′ and pentatrated both skins of a hollow core door and then bridged a 6″ gap and pentatrated the outer skin only of a second hollow core door behind it.
Edited 7/19/2003 11:08:24 PM ET by Z3Coupe
Replies
cool!
Err...I mean...be more safe next time.
It's all fun until somebody puts an eye out, or shoots a cut off through a door.
Safety first! rg
Hi There,
This is the reason why you should always stand off to one side of the saw - I'm glad you were. Never stand behind the board.
As well, please make sure that your fence when ripping is set to be level with the central arbor of the blade - no longer. It avoids to a large extent the forces that cause small bits of stock to be thrown back (kickback), which occurs when the blade rising out of the table catches the stock and throws it back at you.
Also, make sure that the riving knife is set correctly to avoid the kerf closing back onto the blade.
This is "not so cool", but thanks for sharing - I can see your intention was to warn others of the dangerous nature of a kickback.
Cheers,
eddie
eddie
"Make sure your fence when ripping is set to the central arbor of the blade, no longer".
Are you referring to the short fence? Our lingo is a little different north of the imaginary line. ha..ha.. I"m guessing that is what you're referring to. Probably most here will not catch riving knife set center to blade as splitters are the norm. I will post a pic of my home-made short fence (Sgain Dubh inspired). If you look close, anyone interested in the short fence can see what you're reffering to. I made mine to fit over the common long fence we use here. It will slide forward with the twist of two lock knobs on top for adjustment of stock thickness.
If this is not what you're referring too, explain as I'm curious to pick up something new. I think you already know that, though. ha..ha..
G'day...
sarge..jt
Hi Sarge,
I cleaned up your picture a bit so I could see what you were up to and yes, this is similar to any panel saw fence (such as an Altendorf which is adjustable in position in both in/out as well as in front of/behind the blade)
Have attached the brightened up picture as well as another alternative that I was shown which is less permanent and less fancy. I've also seen the same thing done with a cleat to anchor the temporary fence to the table, but I'd hate to see the temp fence launched off the table.
Just for enquiring minds that want to know
Cheers,
eddie
edit: left the large attachment up as it's a full A4 page (8 x 11".) Smaller scans were less clear
Edited 7/20/2003 6:30:09 PM ET by eddie (aust)
eddie
My short fence is a MDF casing with phenolic laminated to it. The two star handles on top are attached to 2 T-nuts that slide in a track on top of the long fence. I can un-screw them an completely remove the short fence in about 30 seconds. I do remove it when I cut larger panels.
I experimented with different thicknesses of wood. I found the exact spot the blade has finished the cut on 1/4, 2/4, 3/4, 4/4, 5/4, 6/4 etc. up to 10/4. The thinner the stock, the closer the short fence rear has to be to center arbor. Added 1/2" or about 10mm an I scribed lines on the fence so I can set it automatically with a given thickness. Works like a charm. Wouldn't be without it except on wide panels.
Yep, the face fence could be added. A lot of the U.S. saws have tracks or can be adapted for tracks. My old junk saw had a riving knife, so I built a removable crown guard to sit on top to counter-act the possible kick from the rear rising teeth. I attached again with T-bolts an nuts. If I unscrew the front one an slightly loosen the rear, the crown can be swung up 90* degrees vertical. Easier to change the blade as I switch frequently between 24 flat rip, 60 cross-cut an 80 finish an laminate.
Back to the shop. I had several friends bring their chisels an plane blades by an drop them off. I wanted to master sharpening free-hand without a jig. About 40 chisels latter and 12 plane blades, by jove I think I have it to a science. I cut my chisel time down to about 3 minutes an plane iron to about 4 or 5. Now, if I can figure how to get all this black-grey metal dust out from under-neath the finger-nails an off the skin. ha..ha..
Take care an pass my regards to the roo's...
sarge..jt
HI Sarge,
Good to hear - sounds like you've got the fence worked out a treat and you're using it as it's meant to be. Neat piece of work, by the way.
Now, if I can figure how to get all this black-grey metal dust out from under-neath the finger-nails an off the skin. ha..ha.. Try lemon juice, the old hands remedy. Over here we have a surface cleaner called "Spray and wipe" - the fluorescent orange antibacterial one takes the iron filings off your hands quicker than the lemon juice. The germs don't stand a chance.
The roos said to say hi -
Take care,
eddie
Edited 7/20/2003 7:59:32 PM ET by eddie (aust)
eddie
You're quick. I just checked messages b-4 heading down to the shop. I will try the lemon juice. Am aware of the orange stuff. It is made from the peel of an orange. Most citric juices are great grease cleaners. With all the nicks an scrapes on the hands, the lemon juice should jolt me awake. ha..ha..
Cheers...
sarge..jt
Those long ripping will really get to humping coming out of the saw - a real spear chucker.
Don't feel alone I did about the same thing a while back I was ripping some 7/16 oak scribe mold 12 ft. long strips by myself with a Ripping blade.
I pushed the strip as far as I could by hand and put my push stick on the molding and began to push it through. Nothing was holding up the other end and as it laid over it bound on the blade .
Those ripping blades will really get a good bite .It Threw that 12 ft. molding 20 ft. hit the wall - went through the 1/2 plywood on the inside and put a real good dimple in the tin siding.
That's not the bad part one of my buddies had walked behind with out me knowing watching- he was standing about 1 ft. away from where it hit the wall.
Can you say Shish- Ka- Chris
Ron,
Forgot to say,
Another way to rip safer when you're doing skinny pieces is to rip 2/3 of the way along the board, then back the board out of the saw, flip the board end over end so that you feed the uncut part of the board into the blade to finish the cut. You are then holding both pieces at all times.
Cheers,
eddie
"then back the board out of the saw, " eeeewwwwwyuck. Never been comfortable doing this. There are proven hold-down/in systems that work great for thin ripping (GripTite is my choice), fast safe and efficient.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
f_g
The saw can be off or on at this point. If you don't feel comfortable, there's nothing to say that the blade has to be spinning.
A bit cheaper than a feed device, which also works well.
Cheers,
eddie
FG
I have used eddie's method. I bump the kill switch on the saw with my knee without releasing the stock. Wait till it comes to a complete stop, then back it out an turn it over. By not releasing, it ensures I don't accidentally move the stock in any manner that will produce a gash in the edge that has already been ripped an initiate a kick-back..
Your grip system is great. This is just an alternative for those that don't enjoy the luxury or if the grips "call in sick" for the day. ha..ha..
sarge..jt
I can vouch for the impact power of a piece of flying wood comeing off a table saw. I got hit in the stomach by a piece about 1.5 inchs wide and 8 inchs long. I did not bleed a lot but left a bruise that lasted a month and a mark thats been there for two months. It was sore for 2-3 weeks.
You and me both. I got hit on the left side of my chest, almost kocked me off my feet actually. The bruise wrapped around and under my arm. Talk about a painful way to reinforce respect.
Does the term "rim speed" mean anything to anybody?
A ten inch circle saw being rotated at 3450 rpm equates to:
And what is the horsepower of the motor turning it?
Maybe someone with more physics background than I can begin to calculate the forces that might be involved!
Some very rough figures: assume the wood is 1"x1"x12" (3.3 lbs approx.), and it goes from 100 mph to 0 mph in approximately 0.08 seconds (a figure I've used for calculating vehicle impacts); then it would hit you with a force of about 200 lbs. That's gotta hurt.
Thanks!
200 lbs of force potentially hitting you over a one square inch area -- gee why don't we just beat ourselves with baseball bats. And the time required to accelerate that piece -- I guess that means that when things like this happen, they happen REAL fast!
The only time I got hit from a kickback was by a 1.5" cube I was cutting from white oak. It hit me at table saw height about an inch to the right of the family jewels. The bruise (black and blued area) was about 6" in diameter. And I never again will do a set up like that.
The rule is to NEVER rip thin stock against the fence (at least not without something to prevent kickback like a featherboard). If that thin strip had hit his gut, I could envision penetration just like that of an arrow.
Reminds me of stories I heard after my first hurricane in Florida, like about a single palm leaf going through a tree because the speed was so high. Who knows if they were true, but the principles applies, I'd think!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I'm sure they're true. I've seen straw sticking out of telephone poles. Granted tornado's generate substantially nore wind than a hurricane but....
At one time I saw a picture of a 2x4 sticking out of both sides of a palm tree as the result of hurricane force winds.
The issue I wanted to raise is that very few individuals understand the concept of rim speed relative to woodworking machining processes. When you start coupling the rim speed of 10, 12 or 16 inch circle saws with 2, 3, or 5 horsepower motors, a blas'e attitude can be very dangerous both for yourself and others.
The additional reality associated with rim speed is the interval between the teeth on a saw. For a saw rotating at 3450 rpm, this equates to having the blade rotating 57.5 times per second (3450/60). If your blade carries 40 teeth that means that every second 2300 teeth are coming at you, or in another way, one tooth every 0.00043 seconds. So how good are your reactions???
If this information scares you -- good! It ought to! Then just maybe, it might raise everyone's level of safety consciousness to a greater level so we don't have to see pictures like those posted and people thinking "Way cool". There are individuals like myself that live in rural areas that were a piece become imbedded in my gut, I could literally bleed to death before help would arrive. And were that not to happen to the extreme, I would still prefer to retain intact things like my kidneys and liver, etc.
I've got a pretty fast reaction time, and lemme tell ya, off a 3hp saw there wasn't time to even notice the chunk of purple heart bouncing off the table, then off my arm before it hit my chest. I didn't really even notice what it was till after everything had happened and it had already bounced off my wifes car as well. The velocity is incredible. Anything that can cause a 3" or so chunk of 1/2" thick wood to cause a 10" or so bruise is moving. In short, I got lucky. Really lucky it hit a major muscle instead of soft tissue or worse.. my face.
If your face is anything like mine, there is great need for improvement. However, I don't think a random hit from a kickback is the best approach.
I've been in sawmills and on the infeed side of splined arbor resaws, there are often bull's eyes painted on walls 50' away from the saws. And there are more than numerous dents and impact marks readily discernible.
Z3Coupe
Ian Kirby has a book "Down to a Line" which is out of print, but can probably be found on line at one of the used book sites. In it he had excellent descriptions of setting up a table saw, and safe use as well as good advice on building rip fence add ons for safe cutting of lumber, sheet goods and milling operations e.g. dados etc. He also describes the proper design and use of riving knives and blade guards. Lots of very useful information. You may have seen articles by him in Fine Woodworking, Wood etc. He recently published an good article on table saw jigs in which he describes a 45 degree sliding jig which obviates the need to tilt the blade for mitering and beveling boards. I built one and it works like a charm.
I too have been belly bruised by the cut off of a piece of hard board which I foolishly tried to remove from the table before the blade had stopped. Nothing more than a bruise, but your experience shows how potentially lethal a table saw can be.
Stay safe from now on.
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