hannes69
ArboristSite Operative
Here some numbers showing why gauge type 2 is mathematically ( ) a good amount better than type 1 (using the Stihl 3/8 RM chain):
Let´s assume a default hard wood setting (a hard wood setting can be used with soft wood without a problem, vice versa maybe not). The new chain is prepared for hard wood, it has a raker depth of 25 mil and a cutting angle of 6.3°. To maintain the hard wood setting, the gauge tool should limit the cutting angle to 0.3° extra but nothing more, so a maximum of 6.6° (set by me in this example like that).
Type 1 gauge is designed with the software´s defaults (47 mil thickness, 566 mil pvot length).
Type 2 gauge is designed with 49 mil thickness to achieve the 6.6° maximum criteria.
So these two designs are comparable now.
Type 1 has a mean value for the cutting angle of 5.8° during the chain´s life, type 2 6.2°. So type 2 maintains the initial cutting angle as mean value to 98.5%, type 1 only to 92%.
Compared to its mean value, type 1 has a variation of +13 % and - 24%, type 2 a variation of + 6 % / -12%. That means half of the relative error! So type 2 has more 'stable' values.
When looking at the relation between aimed value and lowest value, type 1 achieves a minimum of -30%, type 2 only -12%.
Of course both types will work well in reality, but type 2 has a remarkable lead compared to type 1 I think.
Leaving alone the 'small' problem of realizing a 49 mil material thickness (at least for me)
The working principle of type 2 seems better (at least in this case)
Here the numbers for this default hard wood setting type 2:
BTW, if someone wonders about the odd value of 5.9° in between 6.3° and 6.2° for a cutter wearing of 20 mil (comparable 'glitch' in other examples):
This is due to the initial raker depth of 25 mil for a new chain. For 0 mil wearing = new chain this leads to a cutting angle of 6.3°. Because the chain already has this depth. If the chain would have a higher raker, the gauge tool in this example would lead to a raker depth of 21.7 mil and a cutting angle of 5.5° fo the 0 mil wearing point, if we would have to file the raker down from a higher point to our initial value.
The default value of 25 mil helps us at this point
When looking at the numbers of this default hard wood setup type 2 gauge, I consider it and name it "constant cutting angle raker depth gauge", it meets my definition of 'constant' .
Let´s assume a default hard wood setting (a hard wood setting can be used with soft wood without a problem, vice versa maybe not). The new chain is prepared for hard wood, it has a raker depth of 25 mil and a cutting angle of 6.3°. To maintain the hard wood setting, the gauge tool should limit the cutting angle to 0.3° extra but nothing more, so a maximum of 6.6° (set by me in this example like that).
Type 1 gauge is designed with the software´s defaults (47 mil thickness, 566 mil pvot length).
Type 2 gauge is designed with 49 mil thickness to achieve the 6.6° maximum criteria.
So these two designs are comparable now.
Type 1 has a mean value for the cutting angle of 5.8° during the chain´s life, type 2 6.2°. So type 2 maintains the initial cutting angle as mean value to 98.5%, type 1 only to 92%.
Compared to its mean value, type 1 has a variation of +13 % and - 24%, type 2 a variation of + 6 % / -12%. That means half of the relative error! So type 2 has more 'stable' values.
When looking at the relation between aimed value and lowest value, type 1 achieves a minimum of -30%, type 2 only -12%.
Of course both types will work well in reality, but type 2 has a remarkable lead compared to type 1 I think.
Leaving alone the 'small' problem of realizing a 49 mil material thickness (at least for me)
The working principle of type 2 seems better (at least in this case)
Here the numbers for this default hard wood setting type 2:
BTW, if someone wonders about the odd value of 5.9° in between 6.3° and 6.2° for a cutter wearing of 20 mil (comparable 'glitch' in other examples):
This is due to the initial raker depth of 25 mil for a new chain. For 0 mil wearing = new chain this leads to a cutting angle of 6.3°. Because the chain already has this depth. If the chain would have a higher raker, the gauge tool in this example would lead to a raker depth of 21.7 mil and a cutting angle of 5.5° fo the 0 mil wearing point, if we would have to file the raker down from a higher point to our initial value.
The default value of 25 mil helps us at this point
When looking at the numbers of this default hard wood setup type 2 gauge, I consider it and name it "constant cutting angle raker depth gauge", it meets my definition of 'constant' .