PDFWAC 296-806-43006

Use safety blocks on hammers and presses.

(1) You must use safety blocks on hammers and presses when dies are being changed and maintenance or repair work is being done on the machine.
(2) You must provide safety blocks or wedges that meet or exceed the specifications and dimensions shown in Table 430-2.
Table 430-2
Strength and Dimensions for Wood Safety Blocks or Wedges
Size of timber inches using actual
dimensions
4x4
6x6
8x8
10x10
12x12
 
Square inches in cross section
16
36
64
100
144
 
Minimum allowable crushing strength parallel to grain, p.s.i.
5,000
5,000
5,000
5,000
5,000
Note: Adapted from U.S. Department of Agriculture Technical Bulletin 479. Hardwoods recommended are those whose ultimate crushing strengths in compression parallel to grain are 5,000 p.s.i. (pounds per square inch) or greater.
Maximum static load within short column range
80,000
180,000
320,000
500,000
720,000
Note: Slenderness ratio formula for short columns is L/d = 11, where L = length of timber in inches and d = least dimension in inches; this ratio should not exceed 11.
Safety factor
10
10
10
10
10
 
Maximum recommended weight of forging hammer for timber used
8,000
18,000
32,000
50,000
72,000
 
Maximum allowable length of timber in inches
44
66
88
100
132
 
[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060. WSR 15-24-102, § 296-806-43006, filed 12/1/15, effective 1/5/16; WSR 04-14-028, § 296-806-43006, filed 6/29/04, effective 1/1/05.]