Heavy-Tonnage Heavy-Weight Standard Safety Blocks
O.S.H.A. says, "The employer shall provide and enforce the use of safety blocks whenever dies are being adjusted or repaired in the press."
Many materials are available for use in blocking the ram and upper die of a press. However, 6061-T6 or T651 aluminum offers much higher extruded strength per cubic inch of material than other known press safety block materials on the market such as magnesium.
When static load capacity of material is compared, aluminum becomes the clear choice.
Available in many different capacities and in four sizes | Lengths are available from 4" to 92"
Determining Standard Safety Block Length
1) Find stroke of the press.
2) Depending on how block is to be used: With die open (stroke up), measure either the space between the upper and lower die OR the space between the slide (RAM) face and the bolster at the point where the block(s) would be placed.
3) Add (1) and (2) together ~ TOTAL (Also when measuring, consider that the slide is adjustable.)
4) If wedges are to be used, subtract 1½" maximum.
(This is allowance for variation in the stopping point of the crank shaft.)
5) If end caps are ordered, subtract the end cap allowance for the desired size of block.
SB-1 1¼" - SB-2 1¼"
Add/subtract as directed and the result will be the safety block length to order.
Engineering Data ~ Adjustable & Wedge Style Press Blocks
A.) Determine the Safety Block Length
(1) With the die open (top of the stroke), measure the space between the upper and lower die plates or (2), alternately, measure the space between the slide (ram) face and the bolster plate. "Top of the stroke" generally refers to shut height plus stroke. This provides the maximum height of the safety block.
(2) The shut height will generally provide the minimum height of the safety block to be used.
(3) These measurements can often be used for the upper and lower limits on and adjustable block.
B.) Determine the Static Load that is to be Supported by the Safety Block (either standard or adjustable screw blocks)
(1) Add the total weight of the slide (RAM) assembly plus upper die and all components.
(2) Multiply this number by two (2) for a safety factor.
(3) The resulting figure is the amount of static weight that the safety block(s) will have to support.
C.) If static load of the ram and top tooling is unknown, calculate an approximated static load using the following formula. This method contains a built-in safety factor of two (2).press bed area (square inches) X shut height (inches) = total static load (in tons)
1728 (cubic inches in  cubic foot)
D.) Refer to the size safety block that should be used for load by using the product data sheets.
- Many materials are available for use in blocking the ram and upper die of a press. 6061-T6 aluminum offers much higher extruded strength per cubic inch than any other know press safety block material on the market. When static load cpacity of the material is compared, aluminum becomes the clear choice.
- Use only certified material, preferably aluminum. Aluminum is malleable, and will deform. Magnesium is supposed to fracture at a 45 degree angle, but can fracture and cause shrapnel. Steel should never be considered due to potential shrapnel issues.
- .250" of daylight. Under no circumstances should there be more space between the top of the Die Safety Block and the die, or between the top of the Die Safety Block and the slide if the die is absent. It is absolutely critical to accurately calculate the needed Safety Die Block length. An opening greater than .250" changes the force of a moving slide from static to dynamic.
- If two Die Safety Blocks are needed, they should be placed at diagonal corners.
Canadian and U.S. Applicable Standards for Presses
CSA (Power Press) 7. Machinery Requirements
OSHA (Power Press) Standards-29 CFR Part 1910
Canadian and U.S. Applicable Standards for Presses CSA (Power Press)
7. Machinery Requirements OSHA (Power Press) Standards-29 CFR Part 1910
Building Safety Blocks Since 1995
P.O. Box 1149
New Smyrna Beach, FL 32170