table saw safety

[Phil Whitton]

Well for the first time in many years of woodworking, I've had an accident.
Its like the two pilots: the one whose had the accident and the other yet to have one..

Passing a plate of 3mm ply through the sliding tablesaw, and around the back of the blade, the plate caught the edge of the blade and climbed over it, flinging the plate back into my right hand resulting in a jagged tear through the ball of the thumb.

Ive always had a healthy respect of saws as my grandfather lost his fingers in the mill.

Everyone has their own ideas on cutting height settings above the job so I am canvassing a few ideas to rewrite the SOPs for our workshop.

I have the height set at 5mm above to reduce the reverse tearing of sheets.
What do you think?

cheers

[cellist]

Well for the first time in many years of woodworking, I've had an accident.
Its like the two pilots: the one whose had the accident and the other yet to have one..

Passing a plate of 3mm ply through the sliding tablesaw, and around the back of the blade, the plate caught the edge of the blade and climbed over it, flinging the plate back into my right hand resulting in a jagged tear through the ball of the thumb.

Ive always had a healthy respect of saws as my grandfather lost his fingers in the mill.

Everyone has their own ideas on cutting height settings above the job so I am canvassing a few ideas to rewrite the SOPs for our workshop.

I have the height set at 5mm above to reduce the reverse tearing of sheets.
What do you think?

cheers

So sorry to hear of your misfortune. The recommended height is generally considered to be about 1/4 inch (6.2mm), but the 5 mm protrusion should be OK. The kickback problem is always one we have to consider. I recommend using a splitter with spring-loaded anti-kickback pawls (standard equipment). But for many jobs, such as dado cutting and others where the use of the guard is not possible, featherboards and other hold-down methods are worth the effort (as if I need to tell you that now....)

There's a great book by Roger W. Cliffe called "Table Saw Techiques", published by Sterling. ISBN:0-8069-4268-1

Lots of good stuff in there. Recover well and speedily, and thanks for sharing your experience!

Michael

[Alastair]

There is a divergence of opinion on blade height, much debated.

One, much trumpeted in hobby mags, is to keep blade as low as possible, to minimise protrusion, for safety, and ensure that tooth exit from cut surface is shallow, to minimise tearout. Problem with this is that firstly, back of blade is likely to have a "ramping" action, which can tend to lift workpiece. Secondly, above-mentioned shallow cutting angle means that the tendency is for the blade to throw the workpiece in the direction of rotation.

Second philosophy, (incidently the one defined in the wood machining module I completed at TAFE), is to keep the blade at full height except when grooving/dadoing etc. Rationale is that at cutting, blade action exerts a downward force on the workpiece, helping to keep it on the table, and reducing the longitudinal force. Cutting area is also kept out of the cut, reducing heat buildup. Further, if you do get some lifting, it has a lot further to go, before the top of the blade can grab it and throw it at you. Safety of exposed blade, is left to the guard.

I had several painful experiences in the early days, using option 1. Since espousing 2, I have not had a kickback in the last 6 years, despite getting into a few hairy wrestling situations.

You know what my vote is

regards

[silentC]

Yes I am of the opinion that full height is the best for safety.

However, Kelly Mehler says in The Table Saw Book "ask me how high to set the blade and I will ask you how deeply you want to cut your fingers". He also claims that danger of kickback is increased with the blade set high, which runs counter to intuition.

[Skew ChiDAMN!!]

He also claims that danger of kickback is increased with the blade set high, which runs counter to intuition.

I'd say he's technically correct, given a scenario where the fence isn't truly parallel to the blade or the blade has a kink. (eg. a novice woodworkers first TS.)

With the blade fully raised, there's more length of blade in the wood, so any deviation is exaggerated and the back of the blade is cutting a greater thickness on it's upstroke than it would be if the blade was only high enough for the gullets to clear.

Or to put it another way, while kickback is far more likely from a low blade height, the possible severity is a magnitude greater with the blade set high.

I agree that with good technique & a correctly set up TS a high blade is the way to go, but first the novice has to learn how to accomplish both of these...

[niki]

I would recommend reading this article
http://www.waterfront-woods.com/Arti...w/tablesaw.htm

I know Rick from another two forums (Woodnet and SMC), he is an Engineer and wrote Supplemental Owner's Manual for the "Kapex" and other Festool products for the American market.
Good reading for Festool owners...
http://www.talkfestool.com/vb/meet-m...topherson.html


Personally, I like "High blade" but I'm using the blade guard so I don't see any danger in it.

I made an experiment ripping a 30mm thick White Oak once with "low blade" and once with "high blade". With the "high blade" the feed rate was faster, no burn marks and I can use even an 80 tooth blade that gives me very clean edge.

Regards
niki

[justinmcf]

hi, i have two words to answer your question. Saw Stop.

go to sawstop.com.

i am a general contractor carpenter, i will be buying this product, this year.(need to save more money).
if i owned a workshop with employees, i would be buying this product today.

[Old farmer]

Niki, thanks very much for the waterfront link. Very valuable for me and what I need.

[Ian Smith]

hi, i have two words to answer your question. Saw Stop.

go to sawstop.com.

i am a general contractor carpenter, i will be buying this product, this year.(need to save more money).
if i owned a workshop with employees, i would be buying this product today.

Oh dear!! Let's not have that bloody debate again.

Just how exactly would Saw Stop have prevented the injury described by the OP?

Ian

[justinmcf]

you are absolutely right ian. buying saw stop tablesaw would not prevent kickback from the tmber.
but if you pass your hand past the back of the blade, and you get kickback, would you prefer to have a normal saw or saw stop?

i know what i would prefer, and i have employed less experienced people such as labourers, hammerhands, apprentice carpenters in the past.
i know for certain which table saw i would like some of my less experienced employees to be using.

i dont know what debate you are talking about as i am a new member here.
i am trying to look at the bigger picture. after all phil did say he was rewriting his SOP's for his workshop. perhaps part of that is looking at new safer tools.

i used to keep blade 10mm above timber i was cutting, then a mate who runs a kitchen workshop explained to me about the angle of the teeth cutting down into the timber, he recommends blade at 30mm above timber, less teeth cutting into the wood, less friction, less burning. basically same thing old mate rick has wriiten about too.

[Ian Smith]

Justinmcf,
If you do a search of this forum using "sawstop" you'll see what I'm on about.
I realise you are a newcomer to this forum and you may not have seen the previous debates - but it really has been done to death.

My understanding of the sawstop technology is that you have to actually come into physical contact with the blade to trigger it .

You can pass your hand behind the blade, in front of the blade, over the blade and even around the blade, as long as you don't actually touch the blade, so I fail to see the difference between a sawstop fitted machine and non-sawstop machine in the event of a kick-back.

Once a kickback, (which has nothing to do with you coming into contact with the blade, but you might as a consequence) has flung that chunk of timber on its merry way, it's a bit academic as to whether the saw stops, or keeps on spinning I would have thought

Am I missing something?

Ian

[mic-d]

Pushstick, like the ones in this picture keep the work under control, the hands protected. You can push through with them and keep downward pressure on the work. Use them in pairs, one to push, one to keep the work down.

Cheers
Michael

[soundman]

There is quite some debate about all sorts of so called table saw safety issues.

many of the recomendations assume that there is no guard, riving knife or splitter fitted.

So how serious about safety is someone who does not have a guard fitted to their saw.

any way

The blade protrusion thing has been done and there is no simple answer.
Some people are trying to compensate for other problems that should be fixed elsewhere by changing blade height.

Different operations, blades and different materials perform in different ways.

If you are ripping ( solid timber), i believe that balde should be fully raised... because the blade will tend to push the work onto the table at the front of the blade.
there will be a shorter path thru the material.
and
there is a larger portion of blade to tend to keep the work straighter.
The cut quality should be better.

If you are cutting sheet goods, you will be primarly concerned with cut quality......i can definitely tell you different blades work better at different protrusions on different materials..... you will have to do test cuts..... generaly I find that quite a bit more than 5mm is needed for good cuts on laminate.....the blade I use currently works best with about 15 to 20mm of protrusion same blade on radiata ply about 10mm.

For cross cutting heavy stick timber I will generaly have the blade fully raised.

for cross cutting solid timber boards....again it varies with blade and material, but on the blades I currently use i want to see half the gullets.

Personaly i do not consider safety highly ( it is considered) when selecting blade protrusion mostly cut quality, because I believe there are other things that are more important.
I always us an overhead guard and a riving knife unless there is a very good reason otherwise.
I use push sticks and featherboards.
I am very concious of keeping controll of the workpiece

It is just amazing how many safety issues just go away when a proper guard and a riving knife or splitter is used...

I do not like antikick back dogs as fitted to many american saws....I have never seen them on a proper industrial saw...... or a european machine.

Don't get me started on saw stop... eh mic


cheers

[journeyman Mick]

..........However, Kelly Mehler says in The Table Saw Book "ask me how high to set the blade and I will ask you how deeply you want to cut your fingers". He also claims that danger of kickback is increased with the blade set high, which runs counter to intuition.

What a load of tripe! If you followed that reasoning completely the blade would never protrude above the table.

With a properly set up, quality machine, with a functioning riving knife the only chance of kickback comes from operator error. I've spent literally hundreds of hours operating a panel saw and have never experienced kickback. There's been times when ripping stock it's been closing up around the riving knife and jamming up and it definitely would've kicked back without the knife there.
However, if you don't have a quality saw then I'm not sure what the safest option is. When I had a triton workcentre I used to give the back of the fence about 1/2mm extra when ripping solid timber to avoid problems, but I'd still use full blade height.

Mick

[soundman]

I have to agree with mick.....that statement is typical of "American table saw safety"

1. obviously an asumption that is there is no guard
2. why are you fingers that close to the blade
3. the highest danger of kick back may be when the blade is low dependng on the operation. because the work has less distance to rise before getting on top of the blade, particularly thin sheet goods.

I have been reading american books and magazines for over a decade and I have texts that go back 20 and 30 years.

Here in AUS our attitudes toward safety in woodworking have changed incredibly in that time......however the attitudes in the US, at least as published have changed very little, we still see saw benches without guards, ripping without a fence, absence of hearing protection and dust extraction.

When posibly the largest rating woodworking show has regular vision of an old table saw used with no guard and does not get burried in mail about it... there is a problem

I have seen it written and said in videos, how dangerous ripping is on a table saw, and how much safer it is on a band saw.
I can certainly see why the US is so much in love with the band saw.

I have done plenty of heavy ripping on both table and band saw, and I can tell you, If my table saw has the cutting depth I will rip on it every time.
A table saw might take pieces of fingers or a chunk of hand.....but a decent band saw with a proper ripping blade could easily take you hand off at the wrist and not slow down....and that is with all the avaialbel guards in place.

I can see why the yanks are so scared of the table saw.... its because, for a very large proportion of them, there is a blade with nasty big teeth spinning at 5000 rpm staring them right in the face......without the benifit of a guard or a riving knife of any description.

Do not use any american texts as any sort of safety reference particularly those written for and especialy by hobbists



cheers