What is a table saw? A table saw is a very useful power tool to have in your home workshop. Used for fast and accurate ripping, cross, miter and bevel cuts into wood. The beauty of the tool lies in the quality and accuracy of the cut it produces. It does its job and it does it well but if not used correctly it will show no mercy in its retaliation which can result in serious injury or even fatality. In this article we will be looking at the dangers of the incorrect use of a table saw as well as safety procedures and available accessories to limit incidents.
But before we get into that we’ll just take a brief look at the normal operation of a table saw
Ripping: A cut along the grain of a workpiece
Table saw operation
A table saw is essentially a circular saw mounted upside down underneath a flat surface (table) with the blade protruding at an adjustable height. A 10” saw generally being able to produce 3-1/4” thick cuts at 90° and roughly 2-1/2” at 45°. The blade can be expected to run at speeds exceeding 4000 RPM (Depending on the saw model), spinning towards the operator and produces a cut when a workpiece is fed into the blade by the operator. Although table saws can be used to execute a number of different types of cuts, including cross and miter cuts, its main function remains ripping (Crosscuts ideally performed with a Miter Saw).When ripping the operator will set the fence at the desired width with respect to the blade and feed the workpiece through the saw using the fence as a guide.
PHOTO: Workpiece being fed into blade using the fence as a guide.
NOTE: Safety accessories removed only to illiterate sawing.
REMOVING IS NOT ADVISED.
The dangers of using a Table saw
Some people would consider the table saw to be one of the most dangerous power tools in a home workshop. With the two major causes for injury being kick back or contact with the blade.
What is kick back?
When using a table saw to saw wood you are pushing a stock through a blade spinning at 4000+ RPM in the direction of the operator (Blue arrow). With the blade effectively sawing through the workpiece in a downward direction (green arrow). But while the sawing side of the blade is spinning downward the back of the blade is spinning upwards (red arrow). As you saw through your work piece the wood will move over the part of the blade that is spinning upwards and if the blade gets hold of the wood it will throw the piece of wood in the direction the blade is turning i.e. in the direction of the operator. Now imagine the potential damaged done when a stock gets launched by a blade spinning at 4000 RPM. In short, kickback on a table saw occurs when the wrong side of the saw blade grips the stock.
Preventing kick back
At this point I can imagine a few people thinking, “Nope, not for me thank you”, but the point of the article is not to serve as a deterrent but instead motivate safe operation by creating awareness of potential dangers when using a table saw.
Correctly setting the fence will be your first defense against kick back. Ensuring the fence runs parallel to the blade will lead to the workpiece moving through the blade in a straight line and so limiting the chances of the back of the blade getting hold of the wood. If the fence is set incorrectly (skew with respect to the blade) it can lead to the stock being pushed into the side of the blade by the fence effectively pinching the blade.
In addition, most modern day table saws come fitted with a riving knife. Riving knives minimize the possibility of kick back by serving as a barrier to prevent the stock from pushing skew into the blade.
Preventing contact with the blade
“Freddy four fingers use to have 5 until he took up woodworking“
At this point, I wouldn’t think it necessary to explain why you don’t want any part of your body or clothes getting in the way of the blade when the saw is running.
Most table saws have some sort of blade guard mechanism covering the blade. This is a very important safety feature and should always be used where possible.
Flesh detecting table saws – The ultimate table saw safety device
In the 1999 a man with a vision developed a mechanism that would lock up a saw blade on a table saw when any flesh came in contact with the blade. The idea was revolutionary and SawStop was born. The idea incorporates a spring loaded alloy brake that engages instantaneously when flesh contacts the blade. This is achieved by loading the blade with a small electrical signal which is monitored by an electronic control circuit. When in contact with flesh, which is conductive, the signal is distorted which in turn activates the safety brake. The only downfall is the process completely destroys the blade.
Much more recently Bosch Power Tools launched the Bosch REAXX table saw also with flesh detection on the blade. Their aim is to spare the blade incorporates small explosions to retract the blade to a position underneath the table when flesh comes in contact with it. To reset the blade the activation cartridge would need to be replaced (At a cost of $85.00).
These technologies do however come at a price as you can expect to pay from $1399.00 for a SawStop saw and $1499.00 for a Bosch REAXX.
How to use a table saw – The correct way – The safe way
So you have your workpiece that needs to be cut to size.
Start by unplugging your table saw to avoid unwanted start-up’s while setting up the saw. (This happens more often than you’d think). Set your fence to the desired width with respect to the blade making sure it is straight to avoid the stock pinching the blade. After this, you will set your blade height. Normally accomplished with the turn of a knob. The distance the blade should protrude above the stock is a matter up for debate as different opinions on this topic have been expressed. I feel you should set the blade at least double the height of the stock where possible. In this manner, the blade will be pushing the stock down onto the table when sawing.
Others feel, to limit the amount of blade exposed, the blade should be set to a point where it is only slightly higher than the piece of wood you’ll be sawing. But when doing this the blade will be pushing the stock back, needing more force to push it through the saw. And with a blade guard in place, the blade won’t be exposed anyway.
When the saw is set up plug it back in and position yourself slightly of to the side behind the saw so you are not standing in line with the blade. Rest the stock firmly against the fence with one hand and with the other, with a steady constant pace, feed the workpiece over the blade. Using a push stick is advised where possible.
- Don’t use gloves when operating a table saw – the glove can get caught in the saw blade.
- Don’t wear loose clothing and tie up long hair – Lose clothing and long hair can get caught in the spinning blade.
- Avoid cutting wet wood – This can increase the likelihood of kickback.
- Avoid using blunt blades – A blunt blade can cause kickback.
- Don’t stand right behind the blade when cutting – If kick back occurs you are not in the direct line of the projectile.
- Don’t use a warped or in anyway damaged blade – Not only would it result in a poor cut but greatly increase the chance of kickback.
- Always ensure after adjusting the saw that all relevant components are fixed – You would not want the blade to drop or the fence to slip while sawing
A table saw is a useful tool to have. Instead of a time-consuming setup with planks and clamps to set up a fence for your circular saw a table saw sets up fast and produces a neat cut. The convenience comes with the responsibility to practice safe working procedures. So be responsible, work safe and GO OUT AND BUILD SOMETHING.
Like most power tools, table saws are not toys. If used incorrectly a table saw can cause serious injury or lead to fatality. It is always important to use a table saw as instructed by the user manual and never to alter or modify the saw in any way. Always use eye protection.
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