Safety

[echnidna]

This site has good sound advice
http://www.customwooddesign.com/loweringtheodds1.html

[silkwood]

Good site, but it strongly contradicts the general rule I have been told over the years and have just had confirmed by a senior lecturer in wood machining (this doesn't necessarily make him right, just that it makes me trust his judgement a little more).

Having the blade produde only just enough to clear the workpiece, in direct contradiction to the "Lowering the Odds" article" is a very direct invitation to kick-back.The blade should (according to those who I have faith in) ALWAYS be as high as practicable.

I realise their are conflicting viewpoints, as I said I base my perspective on experience and advice. More though, I have been observer in a number of demonstrations where the wood was permitted (actually encouraged) to kick back with the blade in high and then low positions. Through observation it appears (and is backed up by simple theory) that in a high position the wood will kick back, but will usually the catch the top of the blade and be forced back down, repeating the process. This often results in a still dangerous but more likely merely scary event. Some times not, it can still be deadly.

Each time I have seen this repeated with a lowered blade the wood shoots back out at terrifying speed. I have not seen an exception to this.

I would be interested to hear other opinions.

Cheers,

[journeyman Mick]

Gotta agree with you there Silkwood, not only does a lower blade create a more dramatic kickback it will actively cause kickback. A high blade creates high down force, a low blade creates little downforce but plenty of force back against rotation. This makes timber less stable and more likely to vibrate or move around. This means it is more likely to have the blade jam in the kerf or the timber pinch between the blade and the fence. His idea of having the blade low so as to minimise injury due to contact with the blade supposes you are going to touch the blade. If you minimise the risk of kickback, you will also minimise (to an extent anyway) the risk of contacting the blade. If you have a guard fitted then it will make it fairly hard for you to come into contact with the blade anyway. The only time the guard should be removed should be during operations where the blade is going to be mostly covered by the stock anyway.
I also didn't like his method of cutting badly cupped boards, cup side down. Personally I prefer cup up with the stock flat on the table between the fence and blade and the waste cupped up on the other side of the blade. If neccesary you can put a piece of scrap ply on the table to support the cupped side. If the board is twisted as well or really badly cupped I think it much safer to rip with a power saw and then run the timber over the jointer until you have something that is safer to work with.
Most of his other stuff (I didn't read it all) seemed good, commonsense stuff, especially his housekeeping which is all too often forgatten or overlooked.
When it comes down to it the most important safety equipment is your brain. Understand what you are doing, understand the forces at play and understand that if you can't concentrate on what you are doing (because of drugs, alcohol, fatigue or distractions) then it's only a matter of time till you have an accident.

Mick