Safety First!

Last year the school where I teach replaced an older Delta contractor's model saw with the nice table saw shown above.  It is a SawStop brand table saw.  Before we go any further with this post, I wish to mention that I have no financial interest with anything to do with this product.  We chose the SawStop saw for several reasons.  First, it was a high-quality product and was we felt it was a good value.  Second, it's price was very competitive with similar saws in it's class for size and power.  Third, it has the SawStop's patented safety feature.

What is this special feature?

It has a safety device built inside that detects conductivity through the blade.  If something conductive - metal, wet wood, or the operator - is detected, the SawStop's safety device engages.  If you do actually wish to use the saw to cut something conductive, you can determine if what you are going to cut is conductive (before making the cut) and you can dis-able the safety feature if you so desire to make the cut.  (With a key - using instructions provided in the manual.)  When the safety device engages, a perforated aluminum shoe which is part of an expendable cartridge is pushed up into the bottom of the spinning blade by a spring, stopping the blade's rotation and causing the arbor assembly to drop the blade below the surface of the table.  This takes place in literally thousandths of a second.  Check out the time lapse video below:



We've had the saw for over a year now and it has been used without incident by students with a wide variety of experience. Until last Wednesday.

I received a call at about 8:30 in the evening on Wednesday from a fellow instructor to let me know that there had been an incident in his class and that the SawStop safety feature engaged. A student was making a cross-cut on the saw using the miter gage. We're not entirely certain of what happened, but we suspect that the piece of stock that she was cutting was a bit short and not well supported by the miter gage - it should have been backed up with a longer piece of sacrificial stock screwed to the miter gage. At any rate, we believe that the stock pivoted around the corner of the miter gage causing the piece to jam and kick back, taking the piece the student was cutting and her hand into the rotating blade.

A loud "BANG!" was heard by the class (...and likely everyone else in the building!) and the stunned student was standing at the saw trying to figure out what had just happened. The piece the student was cutting was damaged and a small nick was in one fingernail - no blood was drawn. The saw had performed as advertised and likely saved this student a serious injury. The student was shaken, but unhurt and (wisely) chose to head home for the rest of the evening. The cartridge and blade were changed on the saw and after some refresher information about safety in the shop from the instructor, the class continued.

We are all very pleased and relieved that this student was saved from what could have been a debilitating and life-altering injury. Plain and simple.

There is apparently legislation being introduced by the Federal Trade Commission (FTC) to require a device which functions similarly to the SawStop on all table saws. I think the time has come.

There has been quite a bit of discussion by both amateurs and professionals of late about these saws that was spurred by a lawsuit that was filed against Ryobi (I'm not picking on Ryobi - I'm sure there are other lawsuits against other manufacturers, but this one has been quite prominent in the news.)  People who are complaining about the judgement and the FTC requirement say that they are concerned that these safety devices will make people complacent about proper, safe use of these saws.  I've not found that to be the case, personally - when the blade spins up, it's still a 'gut-check' for me.  Students that I've watched working with these saws still treat them with the respect that they deserve.

I strongly urge you to go look at this previous post.   Everything in this post bears repeating and there are probably things that should be added, too.  There is an image in the post which is a bit difficult to look at, but I think it is a good reminder of why you need to be safe in your shop and why these safety features on table saws are important.

Tech Tip Tuesday

On the WoodenBoat Forum, a member posted a thread titled "Boat Building Safety". Ostensibly it was about about the canoe that he plans to build with/for his father and was discussing a picture of Ted Moores in his Canoecraft book. The thread was intended to discuss the WoodenBoat Hat as a "safety item". It brought to mind some safety items that are all too often forgotten in woodworking in general and building canoes in particular.

Wood dust has been noted as a potentially carcinogenic material. Some types of wood are toxic, some can cause allergic reactions, and airborne dust is both a potential fire and explosion risk. If you don't believe me, take a look at this MSDS sheet from JG Architectural Supply, a wood floor vendor from Maryland. After reading it, you'll wonder why the government hasn't recalled every bit of wood grown.

For the reasons noted in the MSDS, you should always have a good dust mask with appropriate filtration to protect your lungs, nose and mouth. Also, to prevent other hazards, a good dust-collection system to deal with dust and shavings created by power tools and a circulation filter to remove airborne dust are really great ideas. They not only help to keep the shop clean, but also help to keep the shop safe. A clean shop is a safe shop.

If you don't believe me that this is an issue, consider the following scenario from the building of a Wee Lassie canoe using three 8" wide, 12' long boards, nominally 1" thick (24 board feet of stock):

• If you start with S4S boards that are nominally four-quarters of an inch thick (really 3/4"), and use a 1/16" thick saw blade, you will turn 3.5 board feet worth of stock into sawdust ripping the stock into strips. (You turn 1 strip to dust for every four strips you cut!)
  
• When you mold cove and bead features on the strips, you will turn another 4.7 board feet worth of stock into dust and shavings. (You turn another strip to dust for every three that you mold!)
  
• Finally, when you fair and sand the hull before glassing, I figure another 2.2 board feet into curly plane shavings and sanding dust. (About 1/16" of thickness removed from the whole hull!)
  

That's a total of about 10.4 board feet that have been turned into dust or shavings in the process - a really amazing statistic considering that you started with 24 board feet of stock in the beginning of the process.

While we are discussing wood dust, don't forget that you want to be protected from all types of dust including from sanding epoxy, fillers (Like fumed silica, glass fiber, micro balloons, etc.) and varnish. When sanding the epoxy before varnish and between coats of varnish, remember that wet sanding works well and keeps the dust to a minimum.

Fantastic Plastic : Redux

A few weeks ago, I put up a post about plastic kayaks. (see here) Matthew Housekeeper from Soundbounder made the following comment:

You make some good points. The plastics introduce many people to the hobby.

This is undeniably true, however, I do have some problems with this. I hate to make a generalization, but people who tend to buy the small, cheap, "cute" rotomolded kayaks, usually have very little training or backround with small boats before they buy them. On the water, these tend to be the people that I see out without a PFD on. They are also the people who can be found in the way of other craft that may have the right-of-way on the water. Sometimes, they are drinking large quantities of alcoholic beverages on the water. They also seem to be the ones who are out in conditions that may exceed their abilities. I doubt most people in these tubby little craft ("But it's as stable as a rock!") have ever deliberately tipped the boat and tried a wet exit and re-entry under controlled conditions, let alone poor conditions.

This is not to say that all people who are out in plastic boats or even these little plastic boats that I describe above are poorly prepared or have little skills. I'm just making an observation based on what I've seen. There are also popular sea-kayaks, whitewater, and whitewater touring boats that are plastic and are paddled by those with excellent background, skills and abilities.

The point here is that these small, inexpensive boats, bring boating to pretty much anyone who wants to paddle. But you should still learn what you are doing out on the water before you venture out and become a danger to yourself and others.

To be equally fair, the same can be true at the other end of the spectrum with the fanciest, most expensive wood or fiberglass boats - paddle, sail and power. They have the money to buy the boat, but not the skills to deal with the situations that may arise out on the water.

Bottom line : if you're going to be operating a boat out on the water, please know what you should be doing, and do it safely.

Tech Tip Tuesday

Today's Tech Tip Tuesday post is about safety. Unfortunately, safety gets glossed over in many woodworking/boatbuilding circles.

This past week the issue of safety hit a bit too close to home. A former co-worker, good friend and student of mine had an accident while using a table saw. Perversely, I consider him to be very fortunate as this was an accident that he will recover from and he is all in one piece. Below are two pictures of this person's hand. They are not pleasant, but they are an excellent reminder to pay attention to safety.


Before the accident, he'd been to woodworking class and had lost a pair of glasses in the parking log at the school. He returned to get them and found them damaged on the ground in the leaves. He arrived home to do some more woodworking in the garage where his tools are. Before he could do that, he had to move the truck that he keeps in the garage. The truck didn't start and he first tried charging the battery. It didn't start. He then added some gas and fired the truck up. At this point, he's tired, and distracted thinking about the glasses and the truck.

This is his view of the incident from the email he sent me:

Basically I was rushing and didn't take the time to make the necessary safety components to make a safe cut and tried to wing it. Well I "winged" it when the part bound up and flipped over dragging the back of my ring and middle fingers. The index got a little cut too but that was a nothing cut.

Safety is the most important concern in the shop.

If you didn’t get that, I repeat - Safety is the most important concern in the shop.

Be sure to read and understand the manufacturer’s instructions and safety recommendations for any equipment that you use. Use common sense and proper safety equipment, clamps and fixtures when working. You’re going to want to be around in one piece to use your canoe after you finish it!

You want to protect yourself from the inherent dangers of the boatbuilding process – there are many of them. You need to protect your eyes from debris, your ears from loud noises, your body from the tools, chemicals and particulates that you will be exposed to during the building of your canoe. Also, do not work when you are tired, angry or distracted – these are some of the most likely reasons for accidents and mistakes. Work when you are well rested, focused and are not rushed. Never, never, never use tools while under the influence of alcohol or medications that may impair you.

• Wear appropriate eye protection, ear protection, gloves and a dust mask as necessary.
• Wear gloves or respirators as necessary.
• Do not wear loose fitting clothes or dangling jewelry.
• Wear sturdy shoes or boots.
• Don't work in a messy shop.
• Don't start a power tool with loose items nearby.
• Don't expose more of a cutter than absolutely necessary to do the job.
• Don't put a portable power tool (i.e. router) down while the cutter is still spinning.
• Make sure you know where others are when you working with tools.
• Communicate.
• Plan ahead before you make your cut.
  
• Don't work with damaged cutters/blades/bits.
• When passing a tool, make sure the recipient has a firm grip.
• Retract blades or tools below the table after use when practical.
• Don't make a cut with an "iffy" set-up. If it makes you uncomfortable, it's probably "iffy".
• Disconnect power when changing bits or blades.
• Hand tools can be as dangerous as power tools.
• Use the right tool for the job.
  

I could really go on and on and on... If you have good, specific suggestions to add, I'd love to include them here.

Please, be careful.

Safety

I had someone comment on the picture below because of safety concerns:

Let me elaborate a bit - the table saw's insert has been deliberately removed. (the big opening with the spinning saw blade is the area we're talking about) By no means is this a standard procedure. You should use the equipment's safety attachments and follow the manufacturer's instructions about proper use of the equipement you are handling.

In this operation, the sliding jig that is clamped to the saw table is being used to cut tapers on the ribs and the by-product of this cut is some long (10") wedge shaped pieces (~3/8" at the thick end) With the table saw's standard insert in place, these wedges get caught very easily and are thrown back at the operator - a big hazard. Without the plate in place, these pieces of scrap simply fall into the saw. This was done at the recommendation of the instructor based on his extensive experience with this process.

In terms of operator safety, you are well away from the blade. The operator's hand sits on the table in front of the opening to guide the ribs and the other hand holds the ribs well back from the table feeding them.

In the future, I'd like to try that operation with a sliding jig that has the handle placed a bit further back so that you are not reaching past the blade when you have to re-set the sliding jig. Also, I'd like to see if a zero-clearance insert would help or hurt the jamming and kick-back of those little wedges. Still, I think I'd want a full face shield, kevlar apron or maybe some armor.

Safety first.

Always.