Handheld rotary saws are great for cutting straight lines, but they have trouble making radius cuts. That can be a problem, because the real world wasn’t laid out with a straight edge.
This video by Mike Sheehan may help whenever you need to make radius cuts in concrete pavers. Sheehan’s technique has four steps:
- Lay out your pavers to cover an area greater than the area you want paved.
- Use a guide, like a length of PVC pipe, to mark your cut on the pavers.
- Make a shallow cut along your mark to score the pavers. This score will help you to guide your blade during the final cut, says Sheehan.
- Make your final cut along your score.
This is a fairly quick and easy way to make radius cuts. So, how do you make these kinds of cuts?
We’ve covered cutoff saw safety on this blog before (like here, here and here). This handout sheet, from Missouri Employers Mutual‘s Worksafecenter.com, is yet another resource in that vein. What’s nice about this one, though, is that it sums up a lot of major cutoff saw safety issues on one page.
Worksafecenter.com’s sheet has five different categories of safety tips:
- Training: Read your cutoff saw’s training manual and get trained in how to use it. Always remember that a cutoff saw is different from a chain saw, so your training on one kind of saw may not apply to the other kind.
- Hazards: Always keep in mind the numerous ways in which a cutoff saw can injure or kill you or affect your health, such as noise and vibration during cutting, silica dust when cutting concrete and other high-silica materials, shattering abrasive blades, flying debris and pinch points along unguarded drive belts.
- Personal Protective Equipment (PPE): Wear your PPE, which will give you some, but not total, protection from the above hazards. PPE should include eye, hand and hearing protection, filter masks or respirators and work boots or shoes that can protect your feet if you drop your saw.
- Inspection: Inspect your blade for wear, cracking, chipping and warping. Make sure your blade guard and belt are installed and properly adjusted. Refuel your saw while it’s cold; don’t take a chance dumping gasoline on a hot engine.
- Best Practices: Make sure your blade matches what you’re cutting and that your saw doesn’t exceed your blade’s maximum RPM. Try wet-cutting concrete to reduce dust and increase cutting speed. Don’t remove the blade guard, and only adjust it while the blade is running. Start your saw properly, while it’s resting on the ground. Never set down your saw or hand it off to someone else while it’s running. And the list goes on from there.
This sheet isn’t a complete list of safety precautions, especially in the Best Practices section, but it can serve as a good reminder after you’ve been properly trained. Just remember what Worksafecenter.com says on this sheet: “A tool with the capability to cut steel or concrete can most definitely injure an operator.” We really can’t add anything to that.
Worksafecenter.com, “Cut-off Saw Safety” (PDF)
We’ve talked about the dangers of silicon carbide fibers emitted by abrasive blades during cutting. There’s another source of breathable silica, though, and you can generate it no matter what kind of blade you use. This silica is generated by what you cut.
According to the Centers for Disease Control and Prevention (CDC), you can generate respirable crystalline silica (RCS), another kind of breathable silica, by cutting materials with high concentrations of crystalline silica, including brick, concrete slabs, block and pavers. The bad news is that RCS can cause silicosis, an irreversible lung condition that can lead to death, as well as lung cancer. (See this Occupational Safety and Health Administration leaflet (PDF) for more information) The good news is that you can lessen your RCS exposure.
The best way to lower your exposure is to wear a respirator or mask while cutting. If you can’t, then the CDC recommends that you attach a wet-cutting kit or vacuum attachment to your saw while cutting high-silica materials. This CDC link includes video of how these two accessories can dramatically lower your RCS exposure and increase your worksite health.
Centers for Disease Control and Prevention, “Engineering Controls for Silica in Construction“
Michael DeLuca at the Baltimore County, MD Fire Department asked us to have more articles about forcible entry. This one’s for you, Michael.
Some firefighters think that forcible entry begins and ends with brute force. That thinking goes something like this: As long as you have enough oomph behind your tool or your kick, you should be able to batter down any door. Makes sense, right?
Not so fast, says Jason Hoevelmann, deputy chief and fire marshal with the Sullivan, MO Fire Protection District. Technique and control are just as important, and probably more important, than strength when you’re forcing doors. His article over at FireRescue1 doesn’t have any new forcible entry techniques, but it does lay out four pragmatic reasons for why you should focus more on skill than muscles when forcing doors.
- Prevention of Firefighter Injuries: Kick a door, and you might break your leg, ankle or foot, Hoevelmann says. Bash it with your shoulder, and you might break your arm or dislocate your shoulder. Any of these injuries can take you out of the fight and cripple your team’s effectiveness.
- Prevention of Victim Injuries: Victims are often found right behind doors during a fire, says Hoevelmann. Smashing down a door can injure adult victims and possibly kill children on the other side.
- Greater Fire Area Safety: Crashing through a door can hurtle you into whatever’s behind the door, like a hole in the ground or fire, before you have a chance to react or regain your balance, says Hoevelmann. That’s a good way to get yourself killed.
- Ventilation Control: If you break down a door, you can create a ventilation hole in the structure that can lead to flashover, a backdraft, or the spread of fire and smoke, says Hoevelmann. On the other hand, using tools and some restraint can keep the door intact and under control, so you can close it and regulate ventilation.
Bottom line: Learn how to use your forcible entry tools, and leave your boots for walking.
FireRescue1, Jason Hoevelmann, “How firefighters can force doors with control“
We’ll be in Booth 943 at Firehouse Expo 2013 from 10:30 a.m. to 3 p.m. tomorrow! Stop by for a look at the Fire Rescue Safety Blade, the fastest fire rescue blade that you can buy, and our other fire rescue tools!
Vladimir Dolezal asked us yesterday for more posts like Monday’s post on forcing padlocks. And then we remembered that we haven’t given our partners Brotherhood Instructors, LLC much love lately…
This video from Brotherhood Instructors shows a fast and easy technique for defeating key-in-the-knob locks. It not only minimizes damage to the door, making it appropriate for medical and similar calls, but it also doesn’t require specialized tools like saws and Rex tools. Just carry a flathead screwdriver in your pocket and you’re ready to go.
Vladimir, this one’s for you.
Remember, we’re in Booth 943 at Firehouse Expo 2013 today and tomorrow from 10:30 a.m. to 5 p.m. and on Saturday from 10:30 a.m. to 3 p.m.! Make sure you stop by while you’re there!