Got Grinders? Get Safeguarding

Safeguarding Standards for Bench and Pedestal Grinders

Grinders are one of the most frequently cited machines during OSHA machine-safety inspections. This is frequently due to improperly adjusted work-rests and tongue-guards on bench/pedestal grinders, as well as a lack of ring-testing for the grinding wheels.

OSHA 29 CFR SubPart O 1910.215 is a “machine specific” (vertical) regulation with a number of requirements, which if left unchecked, are often cited by OSHA as violations. ANSI B11.9-2010 (Grinders) and ANSI B7.1 2000 (Abrasive Wheels) also apply.

Work-Rests and Tongue-Guards
OSHA specifies that work-rests must be kept adjusted to within 1/8-inch of the wheel, to prevent the workpiece from being jammed between the wheel and the rest, resulting in potential wheel breakage. Because grinders run at such a high RPM, wheels actually explode when they break, causing very serious injury, like blindness and even death.

In addition, the distance between the grinding wheel and the adjustable tongue-guard (also known as a “spark arrestor”) must never exceed 1/4-inch. Because the wheel wears down during use, both these dimensions must be regularly checked/adjusted.

“Grinder safety gauges” can be used during the installation, maintenance, and inspection of bench/pedestal grinders to make sure the work-rests and tongue-guards comply with OSHA’s 1910.215 regulation and ANSI standards. Wait until the wheel has completely stopped and the Grinder is properly “Locked Out” before using a “grinder safety gauge”. Grinder coast-down time takes several minutes, which tempts employees to use the “grinder safety gauge” while the wheel is still rotating. This practice is very dangerous because it can cause wheel breakage.

Where grinders are concerned, personal protective equipment (PPE) usually means a full face-shield, not just safety glasses. You cannot be too careful with a machine that operates at several thousand RPM.

Remember, you must DOCUMENT any and all safety requirements set forth by OSHA, as that is their best evidence that safety procedures are really being followed.

Ring-Testing
OSHA says that you must “ring-test” grinding wheels before mounting them to prevent the inadvertent mounting of a cracked grinding wheel.

Ring Testing
Ring-Testing involves suspending the grinding wheel by its center hole, then tapping the side of the wheel with a non-metallic object. This should produce a bell tone if the wheel is intact. A thud, or a cracked-plate sound indicates a cracked wheel. NEVER mount a cracked wheel.

For larger grinders, grinding wheels are laid flat on a vibration-table, with sand evenly spread over the wheel. If the wheel is cracked, the sand moves away from the crack.

To prevent cracking a wheel during the mounting procedure, employees must be very carefully trained in those procedures. This starts with making sure the wheel is properly matched to that particular grinder, using proper blotters and spacers, and knowing exactly how much pressure to exert with a torque-wrench, just to mention a few things.

This OSHA-compliant “Wheel-Cover” allows no more than 90 degrees (total) of the wheel left exposed. (65 degrees from horizontal plane to the top of wheel-cover)
Never exceed these wheel-cover maximum opening dimensions. Larger wheel-cover openings create a wider pattern of flying debris should the wheel explode. A well-recognized safety precaution on bench/pedestal grinders is to stand well off to the side of the wheel for the first full minute before using the machine. Accidents have shown that grinding wheels are most likely to shatter/explode during that first minute.

There is an OSHA Instruction Standard #STD 1-12.8 October 30, 1978 addressing the conditional and temporary removal of the “Work Rest” for use only with larger piece parts based on the condition that “Side Guards” are provided. If this may apply to your grinder(s), make sure that you read the entire thing on OSHA.gov.

Safety Information
Grinding Wheels are Safe… Use but Don’t Abuse

Do

  • Do always Handle and Store wheels in a careful manner
  • Do Visually Inspect all the wheels before mounting for possible damage
  • Do Make Sure Operating Speed of machine Does Not Exceed speed marked on wheel, its blotter or container
  • Do Check Mounting Flanges for equal size, relieved as required & correct diameter
  • Do Use Mounting Blotters when supplied with wheels
  • Do be sure Work Rest is properly Adjusted on bench pedestal, and floor stand grinders
  • Do always Use Safety Guard that covers a minimum of one-half the grinding wheel
  • Do allow Newly Mounted Wheels to run at operating speed, with guard in place, for at least one minute before grinding
  • Do always Wear Safety Glasses or some type of approved eye protection while grinding
  • Do Turn Off Coolant before stopping wheel to avoid creating an out-of-balance condition

Don’t

  • Don’t use a wheel that has been Dropped or appears to have been abused
  • Don’t Force a wheel onto a machine Or Alter the size of the mounting hole – If a wheel won’t fit the machine, get one that will
  • Don’t ever Exceed Maximum Operating Speed established for the wheel
  • Don’t use mounting flanges on which the bearing surfaces Are Not Clean, Flat And Smooth
  • Don’t Tighten the mounting nut Excessively
  • Don’t grind on the Side of conventional, straight or Type 1 wheels
  • Don’t Start the machine Until the Safety Guard is properly and securely In Place
  • Don’t Jam work into the wheel
  • Don’t Stand Directly In Front of a grinding wheel whenever a grinder is started
  • Don’t grind material for which the Wheel Is Not Designed

Source: Grinding Wheel Institute

Rockford Systems Can Help
Rockford Systems offers a wide variety of safeguarding products for grinders.

Grinder Safety Gauge

Bench Grinder Safety Gauge
The bench grinder safety gauge is laser-cut, Grade 5052 aluminum with H32 hardness. The safety yellow, durable powder-coated gauge has silk-screened text and graphics. The bench grinder safety gauge measures 2 3/4-inches wide by 2 1/4-inches high by .1000-inches thick and has a 1/4-inch hole for attachment to the bench grinder.

Standard Mount Grinder Shields
These standard mount grinder shields are available in various sizes for protection from the swarf of bench or pedestal grinders. The frames are constructed of reinforced fiber nylon or heavy cast aluminum. Each shield is furnished with a threaded support rod. The transparent portion of the standard mount grinder shields is made of high-impact resistant polycarbonate to minimize scratching and provide durability.

Direct-Mount or Magnetic-Mount Bench Grinder Shields with Flexible Arms

Double-Wheel and Single-Wheel Bench Grinder Shields
Double-wheel bench grinder shields provide protection for both wheels of the grinder with one continuous shield. The durable shield is made of clear, 3/16-inch-thick polycarbonate and measures 18-inch x 6-inch. A special shield bracket adds stability to the top of the shield. The single-wheel bench grinder shield is made of clear, 3/16-inch-thick polycarbonate and measures 6-inch x 6-inch. This sturdy, impact-resistant shield is designed for use when a single wheel needs safeguarding. These shields have a direct-mount base that attaches directly to the grinder table or pedestal.

Electrically-Interlocked Grinder and Tool Grinder Shields
Electrically Interlocked Grinder and Tool Grinder Shields
These electrically interlocked grinder and tool grinder shields are ideal for single- and double-wheel grinders. When the heavy-duty shield is swung out of position, the positive contacts on the microswitch open, sending a stop signal to the machine control. The safety microswitch electrical wires are furnished with a protective sheath and connect to the safety circuit of the machine that switches off the control to the movement of the grinding wheel. All safety micro switches are mounted in an enclosed housing with an enclosure rating of IP 67. The multi-adjustable, hexagonal steel arm structure allows easy mounting on the most diverse grinders. A versatile clamp allows horizontal and vertical adjustment of the shield. All electrically interlocked grinder and tool grinder shields consist of a high impact-resistant, transparent polycarbonate shield with an aluminum profile support and provide operator protection from flying chips and coolant.

Single-Phase Disconnect Switch

Single-Phase Disconnect Switch and Magnetic Motor Starter
This single-phase unit is designed for motors that have built-in over-loads. Typical applications for these combinations include smaller crimping machines, grinders, drill presses, and all types of saws. The 115-V, 15-A disconnect switch and non-reversing magnetic motor starter are housed in a NEMA-12 enclosure. Enclosure size is 8″ x 6″ x 3 1/2″. It includes a self-latching red emergency-stop palm button and a green motor control start push button. It can be used on machines with 115-V and is rated up to 1/2 HP maximum. The disconnect switch has a rotary operating handle which is lockable in the off position only. This meets OSHA and ANSI standards. For machines with 230-V AC single-phase motors, a transformer is required to reduce the control circuit voltage to 115-V AC in order to comply with NFPA 79.

Danger Sign for Cutting and Turning Machines
Don’t forget to post the appropriate danger signs near all machinery in the plant. The purpose of danger signs is to warn personnel of the danger of bodily injury or death. The suggested procedure for mounting this sign is as follows:
1) Sign must be clearly visible to the operator and other personnel
2) Sign must be at or near eye level
3) Sign must be PERMANENTLY fastened with bolts or rivets

Please call 1-800-922-7533 or visit www.rockfordsystems.com for more information.

Calculating a Safeguarding ROI

In the United States, workers operating or maintaining industrial machinery suffer more than 18,000 amputations, crushed fingers and other traumatic injuries each year. While these injuries vary greatly, the majority of cases do have one thing in common: the injury was largely preventable if machine safeguarding equipment had been in-place, or would have been far less severe.

Many employees, unions and worker advocates may well ask, “Why do we need a safeguarding business case?” “Don’t employers have a responsibility for providing a safe and healthful workplace for their employees?” Although U.S. organizations understand that machine safeguarding is the law and that protecting human life is socially responsible, each company must answer the return on investment (ROI) question their own way. Where does safeguarding fit into a business strategy? Can safeguarding be quantified by using cost-benefit financial analysis? To get to those answers we need to look at both sides of the ledger, comparing the cost of an accident versus the cost of preventing it.

WHAT DOES A MACHINE ACCIDENT COST?
Insurance studies indicate machine safeguarding provides an opportunity for businesses to reduce bottom-line operating costs by eliminating both the direct and indirect costs of an accident, while improving productivity and employee morale. But just how much can be saved? Liberty Mutual reported in its annual Workplace Safety Index that U.S. employers spent $48.6 billion for wage and productivity losses, medical expenses and administrative expenses for workers hurt on the job. This is roughly equivalent to the annual sales of Cisco, Pfizer or FedEx. A study by Colorado State University set the total direct and indirect cost of workplace injuries at a staggering $128 billion.

Safeguarded Press

Direct costs of an accident refer to out-of-pocket expenses like hospital and medical bills. They also include the loss of a worker’s time because of the accident, the lost productivity by the machine involved in the accident being idled or requiring repairs, as well as the other machines further down the production line being shut down. Costs continue to cascade throughout the company with overtime required to make up the lost productivity and new workers who need to be hired and trained. The National Safety Council (NSC) estimates that lost time alone associated with the average injury costs nearly $30,000.

However, costs related to an injury do not end there, as an accident will influence indirect costs far outside company walls. Analysis of most accidents reveal that the actual total cost can range from four to ten times the visible, direct cost stated by an insurance company. For example, a single accident can result in OSHA fines up to $100,000 per machine or more if the violation is found to be willful. In 2010, 24 percent of OSHA’s Top 10 citations for manufacturing dealt with machine guarding violations, resulting in more than $6 million in proposed penalties. In addition, insurance rates can rise dramatically or coverage can be dropped entirely. Investments targeted for company growth may need to be diverted to cover the costs of the accident, while employee morale and productivity can experience a significant drop, and the company’s brand and reputation will likely be damaged by negative publicity. Finally, there are the legal fees, plus management time spent dealing with regulators and attorneys.

Safeguarded Mill Drill
And while it is not calculated as an indirect cost, a poor safety record can make the difference between a company winning and losing bids, especially with government contracts. A plant with a singularly bad reputation for safety may also find itself unable to attract workers at all or may have to pay wages well above market value to do so. Also, if the machine where a serious accident occurred is unique and is locked out for investigation or until the safeguarding deficiency is abated, the company may need to outsource the work at a much higher cost. It’s also possible that the work is so specialized that it’s impossible to outsource and therefore the company loses the business.

DO THE MATH
OSHA’s $afety Pays website (www.osha.gov/dcsp/smallbusiness/safetypays) makes it easy for organizations to calculate direct and indirect costs of an accident. As an example, let’s assume a fictional company with annual sales of $5 million and an 8% pre-tax profit margin has an accident involving an employee whereby his hand was entangled in a drill press.

By using insurance company claims data, $afety Pays can calculate that the crushing accident will cost that company, on average:
• Direct Cost: $56,557
• Indirect Cost: $62,212
• Estimated Total Cost: $118,769

Safeguarded Lathe
By entering profit margin information, $afety Pays will also project the additional sales required to recover the costs of the injury. In this instance, additional sales revenue necessary to cover costs is $1,484,612 based on the 8% profit margin or approximately one third of annual sales. If pre-tax margins are less, the sales impact is even greater.
On the other side of the ledger is the cost to safeguard the machine involved in the accident. For the purpose of this discussion, let’s assume that the same fictional company had an onsite risk assessment performed by a reputable firm that surveyed ten machines on the plant floor at a cost of $5,000, or $500 per machine. Next, assume that the drill press had been safeguarded per OSHA regulations and ANSI standards at a total cost of $1,000. Adding in its prorated share of the risk assessment, total cost to safeguard the drill press would be $1,500, a figure that compares very favorably to the estimated $118,769 cost of the accident.

HUMAN CAPITAL AS ROI
A poll by Liberty Mutual Group insurance showed that the majority of executives surveyed (61%) reported that for every one dollar spent on safety, three dollars is saved. And nearly all (95%) said workplace safety had a positive effect on financial performance. OSHA estimates a 6:1 ratio for saved dollars for every one dollar invested in safety, twice Liberty Mutual’s 3:1 ratio.

Of course, if a company could be guaranteed a positive return on their safety investment, more than half the machines in the United States today would not be operating unprotected. Convincing upper management to commit tens of thousands of dollars on machine safeguarding when a return may not be seen for years can be a hard sell. In this situation, safety professionals should stress that although cost savings are a motivator, safety’s biggest ROI comes in the form of human capital. Money savings from fewer injuries, increased productivity, and higher morale are all additional benefits.

CONCLUSION
Whether driven by the law or social responsibility or the need for a positive ROI, most organizations embark on a quest to make their workplaces safe. The business case for machine safeguarding is solid. By comparing the installation cost of safeguarding over the productive life of a machine versus the direct and indirect costs of even a single accident, it becomes clear that safeguarding makes sound business sense and should be a cornerstone of an organization’s safety goals and objectives.