Episode 104 Stop the Saw!


Wood Shop Safety

c/o a link sent to Marc (The Wood Whisperer) that he then shared on Facebook.

Anyway, enjoy!

SSYTC057 1st Hands-on Experience of the SawStop

At the wood show last weekend, I got to set off the SawStop mechanism, not once, but 3 times.

Funnily enough, I was quite tentative about it the first time – we are talking about an extremely violent reaction at massive speed.

However, in practice it was a lot quieter and more gentle than I was expecting (but just as fast!)  It was amazing just how easy it is to do something stupid, and how capable the SawStop is in allowing you to be able to get away without permanent disability.

You don’t change your work practices (you remain working as safe as ever) – noone wants to set it off even so.  Like airbags in a car, you’d not want to ever see them deployed, but if you did, you would be most grateful they were there.

So here is the video of the very first time I got to set off the SawStop brake.

SSYTC057 1st Hands-on Experience of the SawStop

Thanks to the guys from Gabbett Machinery / I Wood Like for letting me give the machine a workout!

Fence or Ambulance

I could have also titled this “Source or destination”

Would you prefer a fence at the top of the cliff, or an ambulance at the bottom?

Following on from the previous article, there is one thing that has been annoying me with heavy construction, specifically in occupied buildings. Unlike the precautions I take in my workspace (shed), there is so little (as in “none”) control of dust at the point of origin – the construction industry appears to rely on cleaning up afterwards rather than dust minimisation techniques.

While sanding down some of the walls in my home (part of the whole fix-up – I’m getting better at plastering), I’m using the Festool ETS 150/5, with a Cleantex CT36 and Oneida cyclone.  Just on startup, if you don’t wait for the vac to kick in, you can physically see the cloud of plaster trying to billow out, before being sucked straight back into the various ports on the ETS.  The rest of the job, there is no dust, nothing to clean up, even when sanding in the walk-in wardrobe – there was no dust on the clothes at all.  Let alone in my lungs.

Something like the industrial sized Microclene unit for a worksite

Microlene MC3000

or a small unit suitable for a workshop


This is one decent step towards capturing dust that is produced before it fills the room and settles on all the surfaces.

You can improve the collection further by adding a shield to the collector

mc1000-2or even place the unit right at the source of generation.

micro-3Whether that be an air filtration unit nearby, or on-tool dust collection, or a combination of both.

One way or the other, the results are always better when you actively mitigate dust production at the source, rather than cleaning up later.  What would you prefer – using and cleaning a filter, or using your lungs as that filter?

Wearing pleats in the workshop

As a general rule, wearing pleats in the workshop is not the best idea. Other than being just a little too frilly to be shed-like, you’d get a lot of really weird looks from visitors!


Of course, there is a place for pleats in the workshop, and that is in the cartridge of the dust extractor. So why would something frilly be a practical accessory in the workshop?

Many dust extractors use a cloth bag. Cloth bags are great. They are cheap, which is great. They are easy to clean, which is great. And they are great at spreading as much fine dust as you’d ever not want to see around the workshop. Sure, the large stuff gets captured, but that is stuff you can sweep up with a broom and shovel, so one way or the other it is easy to dispose of. The fine stuff will get you every time. In Australia, all wood dust is regarded as carcinogenic.

Many cheap dust extractors would have a cloth bag at the top and bottom. Awesome – two cloth bags to let the dust fly!

sealey-dust-extractor-2hp-240vIt is probably not fair to badmouth cloth bags too much – reasonable ones are running 5 micron, which isn’t much worse than what a pleated filter can achieve anyway.

So what is the advantage of a pleated filter?

A dust extractor pushes through a certain quantity of air. And what goes in, must come out. If you have a cloth bag, the air that leaks through the holes in the cloth to equal the amount of air that is sucked in the hose. As the holes clog, the total amount of air that will flow will decrease. So a filter that is easy to clean is an important consideration. Cloth bags can be banged out, blown out with compressed air, even washed in the washing machine. The limiting factor though, is the total surface area of the filter (the bag).

If you increase the surface area, the total amount of air that will need to pass through doesn’t change, so as the surface area is bigger, the holes can be smaller and still achieve the same through-put of air.

Where it comes to cleaning, pleated filters have a system where you wind or move a handle, that causes the internal baffles to be impacted, dislodging dust and allowing it to fall into the lower half (collection) for the extractor.

Pleated filters used to be only available on expensive dust extractors, but these days you can pick one up to retro-fit to your machine for under $180.

Considering a cloth bag replacement is around the $80 mark, this is a viable, and a superior option.

Even so, in saying that, any dust extractor that is allowing particles back into the workshop environment is not ideally placed. I get a bit of flack on here about my preference in not having the dust extractor in the main shed, but then I’m not breathing air that has been filtered to allow the lightest particles to remain. Once the dust-ladened air is removed, it doesn’t matter how fine the filter is.

However, when used in combination with a good air filter you can get the dust collection, and the air quality you are looking for, or at least closer to achieving the ideal.

So if you have a cloth-bagged dust collector, consider the pleat as a desirable fashion accessory, that is also a desirable feature improvement!

Shed Gremlins

I have been carefully studying these elusive creatures, although as always they are only ever seen slipping into the shadows out of the corner of your eye.

It is their antics which are a dead give-away when you have an infestation.  Tools disappear in plain sight (and just when you have given up completely, the gremlins slip the tool back just where you have looked 3 times already!).  The gremlins are particularly attracted to safety equipment, but are not restrictive – taking squares, pencils, and pretty much anything small, or large.  They really love taking pieces of timber you have just cut and hiding them in your offcut or scrap pile, so you use it as a test piece and then discover you have just hacked into part of the project.

Normal gremlins may come from feeding Mogwai after midnight, but Shed Gremlins need no encouragement.   So long as they have their favourite environment – chaos and mess.  You have to particularly careful as they find sawdust an aphrodisiac, so the more there is spread around the shop, the more likely you will have a full hoard of Shed Gremlins.

This has been a community safety message from Stu’s Shed.

Warning Signs

Hindsight is so much clearer than precognition I must say.

Back when I got my Nova lathe, I mentioned I was getting some small shocks from it.  Annoyances really.  I raised it with the Australian supplier, and that didn’t raise any warning flags either.  As it happened, I saw some tweets from Teknatool (the manufacturer) recently which promoted me to get in contact again, and they immediately responded. That was pretty impressive.

Back to earlier: in hindsight, I, or the supplier should have taken more notice of those little shocks.  You shouldn’t get shocks from an earthed machine.  I know that.  They should have.  But for some reason, I didn’t, and it went through to the keeper.

So fast forward to the present.  As soon as Teknatool heard, they got straight into contact with me, even to the extent of one of their senior engineers ringing me directly from New Zealand to get more information, and to help problem solve it.  Impressive.

Now back in time again, I had tested just how much current was passing from the lathe to the shed (and therefore what was giving me a jolt).  Now if only I had instead tested the earth at the same time, a big red flag would have gone up.  The machine was not earthed.  It is not a double insulated machine (and many of those don’t even have an earth pin): it needs a functioning earth.

I’m not criticising Teknatool / Nova here.  As I will show in the following photos, it is so easy for it to happen.  Perhaps Teknatool should actually glue the earth wire to the earth pin.  Perhaps the tester in the Chinese plant wasn’t as diligent as he should have been.  Who knows, but at some stage in transportation of the lathe, the connector came off the earth, and the tool became dangerous.

Other manufacturers could just as easily experience exactly the same problem.  And all it takes is a very quick check with a multimeter to ensure there is continuity between the earth pin on the flex, and part of the tool itself.

If it wasn’t for an idiosyncrasy of the DVR motor that caused the slight jolt I was feeling when I happened to touch the lathe and the shed (or another tool), I would never have known to even test if the earth was connected.  In the workplace, we regularly (annually) get everything tested and tagged.  Rare to do that at home!

I happen to have access to an actual megger meter so I was able to take the test one step further than simply testing the earth, and that there is no continuity between active and neutral, active and earth and neutral and earth. (All can be done with a mulitmeter.)

Under the specific guidance of the company engineer, I removed the cover from the lathe.



Bit dusty in there!  Before going any further, and it is a bit dusty, check out the awesome indexing wheel! (Sorry about the image quality – iPhone rushed shot)

Once the cover was off, time to work out where the issue is.

Well there’s your problem!  The earth wire from the chassis connection point to the back of the plug is not connected. Once I fitted it, it was obviously tight enough that it shouldn’t have come off easily.  A Chinese Friday on the Superbowl weekend perhaps?

Whatever the reason, this demonstrates that we tend to trust a tool that is new is right, especially when it works without actually checking for ourselves.  I am not condoning opening each new tool to check the wiring inside, but a simple check with a multimeter that the earth is working correctly before plugging it into the shed for the first time is simple, quick, and could potentially highlight a problem easily missed otherwise.

It is a shame basic PATs (portable appliance testers) are so expensive (around $1000).  There is no justification for them to be this much, after all they are not much more than a glorified multimeter, and a basic multimeter can be picked up for $30.  They do test other things – namely the quality of the insulation, but it shouldn’t cost an additional $970 to achieve that!

What I suggest is get yourself a basic multimeter and actually test the earth of your machines.  You may want to consider actually getting one of those testing and tagging guys to visit the shed and test and tag your machines.  Not sure what they charge at street rates – at my work I bring in external companies, and they charge between $2.20/test and $2.80.   If you consider how many tests your shed would represent, that is a pretty small number, and therefore a pretty cheap annual check that everything is still as it should be.

In this case I did have the megger meter, so ran a proper earth and insulation test. 2 ticks, 2 passes.

After all, insulation ages and cracks, rats & mice can eat through insulation, wires inside your cables can flex and break, machines vibrate, and nuts holding earthing straps on can come loose, and we do play with things that can cut cables, or have sharp edges and break a cable pulled over said edge.

Whatever the mode of failure, the older the shed, the longer it has been since things were checked, the higher the chance that something important could have been nicked, cut, snapped, worked free or perished.

Food for thought?

Safety Week Friday (Cost)

Safety costs.  There is no doubt about that – you cannot do it for free.  You can perhaps do it cheaply, for example you can make a reasonable air filter if you buy the correct filter material, and pass air through it, air will be filtered.

Some people can make something like this very easily, and have it work well.  Others may not be so confident, or be time poor, or just simply want a commercial version.  That is often what I tend towards.

Irrespective, safety costs.

Not being safe costs so much more.

When I was first getting my motorcycle licence so many years ago (I was 15 at the time, so that makes it…uh, something approaching 30 years ago) there was a simple line in the guide to getting your licence.  If you cannot afford the safety gear (helmet, gloves, boots, leather jacket & pants, or riding suit), you cannot afford to ride.

Pretty hard lesson.  The motorbike at the time cost me about $300.  The safety gear to ride it would cost over $1000.  So I didn’t start off with the whole lot, and got what I needed to mitigate the most risk.  A helmet, welding gloves, solid footware.  A heavy jacket and jeans: although that would not have been sufficient in a real accident.  Fortunately for me I got away with it, and by the time I had a couple of significant accidents a few years later, I had invested in the gear I needed.  So I broke some bones, but the gear did its job.

In a workshop, a similar concept applies: all the safety gear is needed without question, but there are some safety items that you shouldn’t enter your workshop without.

Where you draw that line is really case by case – I don’t know how you use your workshop to be able to give a definitive answer.  However, some items should be:

dust mask (disposable or otherwise)

eye protection

hearing protection

solid footwear

—————- this is a line.  This is the minimum I have when I go to work in someone else’s workshop.

push stick


—————- now I can use a tablesaw or router table with a minimum of safety (this is assuming the saw has all the normal fittings, guards, fence, mitre gauge etc)

And so on.  When you get sick of always cleaning up the mess, add a dust extractor.  You may be able to not use a dust mask if you have a really good dust extractor, and air filtration.

So to the final surveys: just what has it cost?  Measured two ways: total dollar figure, and percentage of shop value.  For something like a SawStop, count the value as the difference in cost between that machine, and the nearest equivalent without.  My saw is a pretty good one, worth around $2400.  The quality of it is not dissimilar to that of the full SawStop, worth around $7000.  So I’d say the safety mechanism on the SawStop costs about $4500.

Safety Week Thursday (Miscellaneous Shop Safety)

Some good points came out in the comments for the PPE, and although I wouldn’t count them as PPE, they deserved their own category.

So today we ask: what other safety equipment do you have in your workshop?  (And you will have to help me out here, I’m sure there will be lots that I’ve missed!)


Safety Week Wednesday (PPE)

Today is PPE day (personal protective equipment), so let’s see what you’ve got (and use!)  BTW, the answers below (such as not bothering with glasses in the workshop) are not my personal answers, I am just surmising what someone who ticks that box would say!

Again, comments to expand your answers welcome.  Any PPE I missed?

Any other PPE related poll you think I should have included?

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