BACK to
USE and CARE
GAGE BLOCK HEADER PAGE
How to Select Gage Blocks for Use
in Combinations
Gage block selection is a process that starts by examining the last or smallest decimal place
 of the desired combination and eliminating it while subtracting it from the remaining length of
 the desired combination as you proceed.  The process is repeated for each remaining decimal
 place until the total combination has been selected.

As an example:  A desired combination is to have a length 3.9762 in.

1)   Look over the available blocks in the set for a block that has a "2" in the fourth decimal
      place.   Most likely it will be a .1002" block.  (Some sets will have a .0502" block.)

2)  Subtract the selected block from the total length of the desired combination to eliminate the
     last decimal place.
81 piece set
36 piece set
.050 series set
3.9762
- .1002
3.876x
3.9762
- .1002
3.876x
3.9762
- .0502
3.926x
3)  Now examine the next smallest decimal place.  (In this example, it ends with a "6".)  Find
     the blocks in the set that have a "6" in the third decimal place:
81 piece set
36 piece set
.050 series set
.106
.116
.126
.136
.146
.106



.
.056



.
    If you are using an 81 piece set, choose the block that will leave either a "0" or a "5" in the
    second decimal place when you subtract this block from the result in Step 2.    (In this
    example, it would be the .126" block.)

4)  Subtract the selected block from the result in Step 2.
5a)   If you are using an 81 piece set, the selection is about done.  It can be seen from the
        remainder in Step 4 above that a .750 and an 3.000 inch block will complete the
        combination.  Proceed to Step 10.

5b)  If you are using a 36 piece set or a .050 series set, you must continue to examine the
      smallest remaining decimal place of the result.   Choose the block in the set that will
      eliminate the last non-zero decimal place.  (In this example, the last decimal place
      contains a "7".)
36 piece set
.050 series set
Choose:  .170 block
Choose:  .070 block
6)  Subtract the chosen block from the remaining result in Step 4.
36 piece set
.050 series set
3.770
- .170 
3.6x   
3.870
- .070 
3.8x  
7)  Examine the last remaining non-zero decimal point.  Smaller sets do not usually have a .600
     or .800 inch blocks.   These sets usually contain these sizes:

                         .100
                         .200
                         .300
                         .400  (May or may not be included in the set)
                         .500
8)  Choose blocks from the series of blocks listed in Step 7 above that will add up to the
     remaining decimal place calculated in Step 6.  In this example, the choices would probably
     be:
36 piece set
.050 series set
Choose:  .100 block
              .500 block
Choose:  .300 block
              .500 block
     Note:  Other choices could be made as shown below.  But, it is recommended to keep the
     number of blocks in the combination as small as possible.  
36 piece set
.050 series set
Alternate choice:
(Not recommended)
Choose:  .100 block
              .200 block
              .300 block
Choose:  .100 block
              .200 block
              .500 block
9)  Now that all that remains is the whole number of inches in the combination.  (3 inches in the
     example.)  If the set has a single block of the desired length, choose it.  Otherwise, a
     combination of blocks will have to be selected.  In our example, it is more likely that the
     3-inch size will have to be built up from 1-inch and 2-inch blocks. 
36 piece set
.050 series set
Choose:  1.000 block
   and      2.000 block
Choose:  1.000 block
   and      2.000 block
10)  Double check the combinations by adding together all the selected blocks.
81 piece set 
36 piece set
.050 series set
.1002
.126  
.750  
3.000   


           
3.9762  
.1002
.106  
.170  
.100  
.500  
1.000    
2.000    
3.9762  
.0502
.056  
.070  
.300  
.500  
1.000   
2.000   
3.9762

Metric gage block selection is performed in the same manner.  Always start with the last or
 smallest decimal place and eliminate it with your choice of blocks while you subtract it from
 the remaining length of the combination as you proceed.  Repeat this procedure until the total
 combination has been selected.

Example:  Desired combination length of 150.932mm

1)  Examine the blocks in the set that have a "2" in the third or lowest decimal point.
112 or 88 
piece sets
45 pie
ce sets
1mm base set
2mm base set
1mm base set
2mm base set
1.002 block   
2.002 block  
1.002 block  
2.002 block  
Choose: 
2)  Subtract the chosen block from the size of the desired combination.
112 or 88 
piece sets
45 pie
ce sets
1mm base set
2mm base set
1mm base set
2mm base set
150.932  
- 1.002 
 149.93x    
150.932  
- 2.002 
 148.93x    
150.932  
- 1.002 
 149.93x   
150.932  
- 2.002 
 148.93x   
3)  Choose a block to eliminate the next smallest non-zero decimal point.  If using an 88 or 112
     piece set, choose a block that will leave either a "0" or a "5" in this decimal place.
Choose: 
1.43 block
2.43 block
1.03 block
2.03 block
4)  Subtract the chosen block from the remainder in step 2.
112 or 88 
piece sets
45 pie
ce sets
1mm base set
2mm base set
1mm base set
2mm base set
148.93  
- 1.43 
 148.5x    
148.93  
- 2.43 
 146.5x    
149.93  
- 1.03
 148.9x   
148.93  
- 2.03 
 146.9x   
5)  Choose block to eliminate the next smallest non-zero decimal point.  If using an 88 or 112
     piece set, choose a block that will eliminate the first whole millimeter decimal place as
     well.
Choose: 
8.5 block
6.5 block
1.9 block
2.9 block
6)  Subtract the chosen block from the remainder in step 4.
112 or 88 
piece sets
45 pie
ce sets
1mm base set
2mm base set
1mm base set
2mm base set
148.5  
- 8.5 
 140.x    
146.5  
- 6.5 
 140.x    
148.9  
- 1.9
 147.x   
146.9  
- 2.9 
 144.x   
7) Choose blocks to equal the whole millimeters left in the combination.
 
45 pie
ce sets
112 piece set
88 piece set
1mm base set
2mm base set
 100.0
25.0
15.0
100.0
40.0 
90.0
50.0
7.0
90.0
50.0
4.0 
8) Verify that the combination of chosen blocks equals the desired length. 
112 or 88 
piece sets
45 pie
ce sets
1mm base set
2mm base set
1mm base set
2mm base set
     1.002
   1.43
  8.5 
100.0  
   25.0    
   15.0    
 150.932
     2.002
     2.43  
     6.5    
 100.0    
   40.0     
             
 150.932  
     1.002
     1.43  
     1.9    
   90.0    
   50.0    
     7.0    
 150.932
   2.002
     2.03    
     2.9      
 100.0      
   25.0       
   15.0       
 150.932   
BACK to
USE and CARE
GAGE BLOCK HEADER PAGE
GB49
©2008, Webber Gage Division, The L. S. Starrett Co, Cleveland, Ohio , 44145
INDEX