Holistic Safety

Holostic, from ὅλος (holos), the Greek concept that the properties of a system cannot simply be determined or explained simply by looking at the individual component parts. Aristotle summarised it particularly well – “The whole is greater than the sum of its parts”.

Safety is a system, and it too is greater than the sum of its parts.  You cannot just take a push stick, a dust mask, some hearing protection (etc) and be able to declare “Now I am Safe”. Only when everything is working together seamlessly is the system complete, and greater than the individual safety steps employed.

Instead, look past the individual components of a safety system and look at how and why our workplace may, or may not be safe.

What I am proposing is looking at the dangers and risks overall, and the finding a system to manage them.

When you walk in the door of your workshop, let’s assume at least until that point you are healthy, and safe.  The objective is to therefore leave the workshop in at least a good a condition (if not better, after all, any shed time always improves my sense of well-being!)

Let’s also assume that the workshop is relatively safe to be in – the atmosphere is not polluted with contaminates, walking around isn’t causing clouds of dust etc. So we are still safe.  So what changes?  When does the workshop go from being in a safe to unsafe condition?  When things are moved and/or started and/or used and/or opened. In other words when we do things in the workshop, so our actions create an unsafe workplace.

If things are stored correctly (timber stacked properly on woodracks, sharp edges not protruding, trip hazards removed or controlled etc) they we should be free to move about the workshop without incident.

Already we are starting to build up a safety system concept.  Everything has a place to be stored, our working environment has a degree of separation from the tools and materials.

When we decide to use a tool, whether it is a sawhorse to hold some timber, a handsaw, chisel, plane, clamp, tablesaw, powered hand tool etc, it needs to be in sufficient condition that it operates as intended, and designed.  Tools meant to be sharp need to be sharp, surfaces that timber is meant to slide on easily should slide easily and so forth.

So the next concept to be integrated into the system is maintenance.

Add another concept – knowledge/experience.  You’ve sufficient knowledge of the machine from past experience, and/or have read and understood the instruction manual to the point that you know how to use the machine as it was intended and designed.

So let’s then focus on an example – using a main workshop machine (such as the tablesaw – after all it would be fair to say it is regarded as one of the more dangerous workshop machines).  It would be fair to say that a machine that was designed correctly, if used as designed, will work safely.  So where is the danger, the risk? By not using the machine correctly.

Set the fence with the tail towards the blade, you get a choke point, and kickback.  Use the saw without a fence, and you are likely to twist the material, get a jamb, and kickback.  Use too much force (and slip) or incorrectly position your hands, and there is a major injury.  A saw won’t cut you unless you present it with something to cut, it won’t throw something at you unless you give it something to throw, or bind on the blade.

A tablesaw is designed to do one thing – spin a bunch of tiny chisels in one plane, and pare away timber causing it to be severed in that plane.  What does it need for that?  A tabletop to support the material and a motor driving a blade. Everything else is used to improve the safety of the operation, and ensure the machine can only do its primary function.  A tablesaw fence? Safety equipment. Mitre Gauge? Safety equipment.  Splitter? Same. Guard? Same again, and so on.

A tablesaw can be used by turning it on and pushing material into it without any other item being bought into play.  But it isn’t safe to do so until you start to utilise the safety system.  Supporting the timber with either a fence or a mitre gauge, extracting dust, setting a proper blade height, extracting dust are all safety steps.  As is the use of featherboards, push sticks, anti-kickback devices.  But the system fall down if components are left out.  A featherboard is useless without the fence.  A fence isn’t as good without a splitter.  Splitters not as useful if material is not properly supported into, out of, and through the blade area.  A 6″ exclusion zone for fingers around a blade.  All this is make sure the machine only does its primary function – cut the timber in two.  Not create a missile (kickback), cut you, catch clothing/hair, jamb, splinter, smash and/or burn (rather than cut) The safety system is more than a sum of the components.

There is the primary function, and result from a machine, but there is also a secondary effect.  A saw may cut boards in two, and if you used enough of the safety system you can do so without incident, but only if you deal with the consequences.  The consequences of cutting timber in two include: relieving internal stresses in the timber so it potentially twists and warps, turning the kerf-width of timber to dust and throwing it into the air, creating larger particles to fly off, and noise.

So the safety system now includes (not limited to, nor necessarily requiring one, more, all or even any of the following) dust mask, dust extraction, eye protection, hearing protection, leather apron, dust filtering and collection.

So don’t look at safety devices as being optional, or secondary to the woodworking operation – they are an integral part of what makes the woodworking experience enjoyable, and ensures that you leave the shed in at least as good a condition as when you entered it, if not better.  Look at the collection of safety items you use, and safety practices you employ as an overall system – as that system is greater than the sum of its parts (and that also works in reverse – leave out a part of the safety system, and the system as a whole suffers more than the subtraction of that part).  Approach safety holistically, not individually.

A system does have to work for, and with you.   It may be practical safety to wear every bit of safety gear, buy every safety item on the market.  Practical, but not necessarily practicable. And that is the subject of tomorrow’s discussion.  Safety Practicability in the Workshop.

Safety Week

Safety Week for the Woodworking Blogosphere begins again (with a slight delay), so from Monday, for 5 days, there will be a post a day specifically focusing on different aspects of safety. Not only here on Stu’s Shed, but across a significant proportion of the woodworking bloggers websites. I will be contributing my own entries, and will provide links to others that surface during the week, all summarised on the Safety Week 2010 tag above.

At the end of Safety Week 2010, my entries will be amalgamated into this site’s Safety Page.

Safety Week 2009

The first complete week in May is again Safety Week for Woodworking Blogs, so over the next 5 days I will be covering a number of safety related topics.


These posts will also be consolidated under the “Safety” tag at the top of the page, as are the previous safety posts, so for an every-growing collection, that is a reasonable place to start.

Hope they prove to be of value to you!

Safety Week 2009

Well Safety Week is rapidly rolling around once again in the Woodworking Blogosphere, where collectively we address a number of safety issues in the first full week in May.

I’m starting to pull together a few ideas of what I will cover, and so far the list looks like:

MagSwitch Featherboards

Air Flow in Dust Extraction Piping

Fire fighting with immediate response devices (eg fire extinguishers)

That’s about all I’ve come up with so far.  More to come I’m sure.

2008 Safety Week Wrap

So that was safety week on the Wood Whisperer Network. Hope you got something out of it!

It seems from reading around, it is the same mistakes being made over and over and over…..and over and ov… (alright, enough)

What is it, that it takes a personal experience before we often will start doing the right thing? Advocates of pushsticks are often those who copped a massive kickback, machinery guards by those who have been cut, electrical safety by those who have been stung, material handling by those who can no longer lift without pain and so on. The whole OHS movement (if I can call it that) is constantly berated for being too pedantic, for making things too hard, for being too over zealous. It doesn’t do itself any favours because that is true to a certain extent, but the principle behind it is harnessing the collective wisdom to prevent injury before it occurs.

What I was talking about in the first video at the start of the week touched on this topic. Sure, safety devices are wonderful things, but they have to work for, and with the individual. If they make the job harder, less safe, are too cumbersome etc, then they will be abandoned. I don’t want myself or others to not use safety equipment, I want safety equipment to be designed to work with the activity, rather than hinder it.

Safety glasses and ear defenders are not too bad in their design and implementation, but dust masks are still poor. Perhaps the concept is too hard, or the thinking is “if you need it, you’ll put up with the poor design”. They are generally not comfortable (especially in hot weather), there are straps everywhere and more often than not it becomes a fight on the face between the mask, the glasses and the hearing protection.

There are ways to alleviate the situation…somewhat. Dust collection on the machine and dust filtering the workshop air all decrease the hazard posed.

Air cleaners such as this from Carbatec for around $370 are worth considering

To quote from their site “Once you’ve finished cutting and sanding operations and have turned off your dust extractor and protective mask, you might think you’ve been sufficiently safety conscious about protection from dust inhalation. However when you see a ray of sunlight come through window you can see that that a lot dust remains suspended in the air.” I know for a fact the same is true in my workshop, and by the end of a good day’s woodworking, my lungs are not so contented. So this is part of my workshop poor practice that I want to address.

So what else is there that suffers from the same “either the safety solution is perfect or I won’t use it at all” mentality? I’ll leave that to you to think about for your own workshop. What guards do you leave off, what safety gear do you not wear, what safety aids do you ignore because of the extra time, and hassle it is to include them? Give some thought to why this is so. If it is because they make the job harder, even increase the risk? Then don’t abandon the concept – find a better device! If your saw guard annoys the hell out of you, find a different design, if your safety specs make it harder to see what you are doing, get some new ones.

Don’t become a safety zealot only once you’ve suffered an injury. There are enough of them already (and good on them for raising people’s awareness), but let’s not continue recruiting to their ranks. Safety is much better as a preventative, than it is as at preventing a re-occurrence!

Work smart, work safe.

Safety Devices

This is a topic I wanted to cover as part of the Safety Week 08 as a video, but I don’t have a good enough range of devices yet to really do the topic justice. So I’ll write a bit about it instead!

What I’m talking about here are on-tool safety devices, and onces that we use to improve our material handling (primarily keeping things we want to keep away from the cutters!)

There are a whole raft of devices: push sticks, holddowns, featherboards, splitters, riving knives, guards, anti-kickback pawls etc and so the list goes on.

There are two primary things all these safety devices are trying to achieve: keeping your bodyparts away from the cutting things and/or stopping the cutting thing throwing the material at you at very high speed.

Before I go on, there are some rules. (In fact it seems many of the rules and instructions provided with machines can be generalised into stopping the tool biting you, or incorrectly eating the material it is being fed. I guess the code violation of reading the instruction manual may have to be overlooked if you want to be safe!)

The rules are: no loose clothing, hair tied back (unless your haircuts are as short as mine!!), no jewelery, no rings, no gloves. There are lots of don’ts. If you look at the list, it can also be generalised. Don’t provide the machine anything that it can snag on and pull you into it. It happens a lot – don’t become a statistic.

The first category of devices are ones designed to stop you getting cut. These include pushsticks, machinery guards and techniques. The first two are obvious – keeping your hands away from the cutters so you can manipulate the workpiece from a distance, and blocks so if you do stray too close there is something there to impede you from getting to the cutter.

Techniques though? Perhaps not the best term, but I’ll explain what I mean. There are a number of things you can do to reduce the likelihood of an accident occurring. Keep the blades sharp (????!!!!!), keep the machine lubricated, especially the contact surface between the machine and the material, operate the machine at sufficient speed, don’t over-tighten the material holddowns (ie so they are not pushing too tightly onto the work). All these will achieve one thing – preventing you from being tempted into applying too much pressure when feeding the material into the tool. The more you push, the more likely you are to slip, and fall into the blade. On the other hand, the easier a piece of wood slides nicely into the tool and out the other side, the safer it is, the finer the finish, and the more enjoyable the whole woodworking experience. What would you prefer – having to fight to get the material in and through the machine, or have it glide on past?

Back to the other two – guards are obvious. Well, so are pushsticks, but they get avoided so often. I think the reason they are is because of that loss of feeling and control for you as the operator. If you are physically holding the material you can better control where it is going, and how hard it is to get it there. We recognise the need for a pushstick, but are concerned about loosing control of the workpiece. So get a better pushstick! And use some of the anti-kickback devices so the concern does not have to be there in the first place.

The basic pushsticks consist of a handle, and a small notch to push on the work. Sure they do that, but there is nothing stopping the workpiece skewing and getting caught (and thrown). They are also a point-contact, so for example the back of the blade of a tablesaw can start to cause the workpiece to lift (and potentially be thrown again).

As much as they keep the hands clear, they are a poor design. Pity so many of the commercial ones are just this type.

Instead, how about ones that not only feed the work into the device, but also hold the work down on the table?

This (from Taunton’s Fine Woodworking) is just one design, but you get the idea- it pushes from behind and still holds the work down.

Couple this up with some sort of featherboard, and the workpiece is controlled, unlikely to float (what I call it when the rear of the blade lifts the work up – it looks like it is floating on a jet of air), and pushed through with your hands clear of the blade.

You can also have featherboards holding the work down, as well as against the fence, as seen here with the MagSwitch version of a featherboard.

There is no reason why you can’t make your own pushsticks and featherboards – the important thing is to have them, and use them!!

So now we are moving onto stopping the work being thrown. Commonly called a kickback, the tools, such as a tablesaw, can propel your project towards you at speeds approaching 200km/hr. Believe me, they hurt when they hit! Never mind what you were working on is probably wrecked in the process.

There are all sorts of reasons why a kickback occurs, but it all boils down to one thing – instead of cutting, the tool somehow managed to get leverage on the workpiece. It could be that the kerf on the wood closed at the back because of forces inside the wood that were relieved during the cut, causing it to close on the blade, or you slightly skewed the piece so the back of the blade got a good purchase. It could be a misaligned fence, or (such as with a router) you fed the material in the wrong direction.

There are devices to try to prevent these occurring, such as splitters and riving knives, anti-kickback pawls, featherboards and board buddies (a kind of wheeled featherboard, where the wheels can only rotate in one direction)

I’m getting a bit of track here, so let me drag it all back to this:

To be safe during a cut, you want to keep yourself from being machined (to not split hairs here), nor do you want to be hit by self-made missiles.

By using guards, pushsticks and holddowns, combined with correct techniques, your chance of a mishap occurring is greatly reduced.

Safe woodworking.

Main Machinery Operating Noise

As discussed in the previous post, I took a sound meter around the workshop to get an idea of the different machines and the amount of noise they generate.

To qualify these figures, the machine in use was out-of-spec, so the readings should not be taken as gospel.

A reading of 85dB or above means there is a risk of permanent hearing loss.
100dB gives a max allowable exposure of 15 minutes
110dB – hearing damage likely after 60 seconds.

Remember that the time is cumulative. I don’t know over what time period (probably in 24 hours)

A 3dB increase in volume represents a doubling of the sound energy. Because the scale is logarithmic, a 10dB increase in volume represents 10 times the amount of sound energy, which will sound twice as loud.

Shed Ambient Noise: 58dB

Tablesaw: no load 85dB
With a non-noise limiting blade that had a resonance with the TS, 105dB
During a cut: 95 – 100dB

SCMS: no load 110dB
During a cut: 120dB – 125dB

Thicknesser: no load 106dB
During a cut: 110 – 120dB

Lathe: no load 62dB

Jointer/Planer: no load 80dB
During a cut: 100dB
Forcing the cut: 110dB

Drill Press: 85dB

Bandsaw: no load 70dB
During a cut: 100dB

Router: 100dB

Circular Saw: 115dB

Nail Gun: firing 126dB
During disconnect: 124dB

These figures are not as accurate as I would have liked (limitation of the equipment), but it gives a pretty fair idea that thicknessers, brushed motors (SCMS and circular saws) and in general during an actual cut on other machines, hearing protection is mandatory.

The screaming motor of a thicknesser which is often used for quite long jobs, multiple passes will leave you with permanent loss every job.

The sound a nail gun produces may not last more than a fraction of a second, but that instantaneous sound will lead to a hearing loss that is less temporary.

Some interesting findings out of all that: Increasing the pressure during the cut can increase the sound energy ten-fold. This can move a sound from needing 15 minutes to damage your hearing to one that will take 60 seconds to do the job.

Brushed motors are bad news (my thicknesser, SCMS, circular saw)

If something sounds loud, and particularly louder than something else, the amount of sound energy required to achieve that increase in volume is huge. If something sounds loud, be sure that your hearing needs your intervention!!!!

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