Circular saw safety

[JayJay1978]

Some of you will have seen this and some not, its scary I couldn't even watch it he was lucky.

Be safe..

 

[Deleted member 174758]

He's right about the lack of riving knife and crown guard being at the heart of the issue, but his idea of a good push stick/block is woefully inadequate - you should never use a push stick/block which allows your hands to get nearer to the cutter than about 12 to 16in (I was taught 12in, the modern advice is now 16in) and certainly never use a push block like he does and run it past the cutter.# because those stupid things place your hands far too near the cutter (they are, incidentally, banned from use in industry on H&S grounds). It's maybe worth considering that a 10in (250mm) saw blade has a peripheral speed of over 100mph and that in a kickback that velocity is transferred to the timber - little wonder that I don't believe anyone who says that they can sense a kickback coming and step out of the way.

Thanks for posting, very informative

 

[rsgaz]

a 10in (250mm) saw blade has a peripheral speed of over 100mph

And then some! A 250mm blade at 2950rpm comes to 173mph!

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[big-all]

you will never preempt kickback
but you will by removing all support and drive cause it to happen
especially if you do it in a "knee jerk" jumpy fashion
kickback will only happen when the force holding and guiding is less than the force imparted by the blade in action

 

[Deleted member 174758]

And then some! A 250mm blade at 2950rpm comes to 173mph!

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Great! Another genius using a saw without a riving knife, or a crown guard, and with a rip fence that's too long - at least he's using proper push sticks (even though they are a tad on the short side)! Sorting out that "misalignment" still won't save you from having a kickback, though, a "short" rip fence will get you a lot further. Worst kickback I ever had was ripping some 10 x 2in kilned black American walnut a number of years back: the stuff was so full of stresses that it twisted in around the back of the blade and even with the riving knife and crown guard I found a 12 foot length of walnut being propelled backwards past me at a rate of knots. Fortunately I was standing in the right place, to one side, rather than directly behind the stock so the min damage was to my pride. That was a 16in rip saw with a 7HP motor, so it imparted a fair amount of energy back into the timber - enough to fire it about 20 feet across the shop. I have to say that it was a rare incident, but it's not the only kickback I've had over the years - but I don't have many.

Anyone interested should download leaflet WIS 16 from the HSE website - free, good advice on using table saws

 

[Roger928]

Split 6 foot of mahogany on 3 phase saw and the operative on the out feed side of the saw let one piece fall unto the blade and it came at me like a javelin hitting me on the side of the face and hitting the door behind where it left a big dent.
Woodwork teacher was out of class momentarily and I wanted to crack on with my project. I was 14 at the time as was the operative assisting me.

 

[mwatsonxx]

Good info, should be put in the wiki as warning to everyone.

 

[mattylad]

I have a scar on me left little finger due to using one with no guard on at work when I was 17, now I'm one of the few at work that will go near the big circular saw to cut some MDF as I treat it with the utmost respect and use a long pushy stick.

 

[^woody^]

IIRC there is a yank brand of saw that will cut out as soon as it detects flesh on the blade.

 

[Aquaheat]

IIRC there is a yank brand of saw that will cut out as soon as it detects flesh on the blade.

First thing I thought of when I read this post.

It was called saw stop and the guy put his finger onto it to test it. Works on conductivity.

Jon

Video here:

 

[big-all]

your finger will be very badly damaged even with that system

 

[Roger928]

your finger will be very badly damaged even with that system

Didn't you see the sausage test. It only receives a slight nick.


Unfortuanetly the blade is trashed and the saw imoperable until parts are sourced.
Unless you happen to have spares.
The bosch reaxx might be a better system.
I think bosch and sawstop were lawing each other.

Personally I don't see any use for table saws on site. I can do everything they do and more with my rail saws.

 

[big-all]

in the real world hands move at metres per second not mm per second
it relies on surface conductivity so a wet sausage will give an instant circuit where as a finger will not

 

[Roger928]

where as a finger will not

So you're saying the technology is flawed?
That being the case why did the inventors finger trigger the mechanism in the above video?
The saw stop has been around for about 10 years afaik. So surely the saw stop inventor should have been litigated by this stage by fingerless users?
Aside from the safety gimmekry it looks like a quality piece of equipment.
Similar to the Powermatic machines. That you never see here.
Mebbe now that were leaving the eu we will get those big dado arboured machines released to the diy masses?

 

[big-all]

what i am saying is whilst it will operate several teeth will contact with the finger or hand
in general a hand approaching a blade is due to an accident often from over balancing or may be kickback throwing the wrongly held timber out the way whilst your hand that was pushing the timber now contacts the blade
saws are supplied with guards and if properly fitted and adjusted you cannot come into contact with the blade