Originally Posted by
megafiddle
Not sure why the hammer would have to cock further. The escape edge hasn't changed from that of a 90 degree primary. The tips of the hammer hooks do not have to move up any further to clear the rear edge (the escape edge) of the 87 degree sear. And the front edge of the 87 degree sear is at the same height as the escape edge. Both front and rear (escape) edges are the same distance from the sear axis.-
It will cock further if the hammer hook tips overhang, because the hook tip face plane is not on the hammer pivot enter. So the tip is below the sear. If the tips land say in the center front to back of the sear they will cock further as the center of the primary plane is closer to the pivot as you have changed the geometry from a right triangle to an isosceles triangle.
Pythagoras theorem, is easily used here. a2+b2=c2, a can be the distance from the pivot center .404" for instance and b is then the distance from the escape edge to where the hammer hooks land, say .012", considering the sear is .030"and with shorter hammer hooks is actually a lot. So that means c is the distance from the point the hook tips land on to the pivot center. So, c is .404178178, which means the hammer hook tips are landing on a spot that is .000178178" higher than the escape edge.
Originally Posted by
megafiddle
Yes, the real change is in the engagement polarity as the sear rotates. With a 90 degree .030" sear face (no secondary relief cut), the engagement polarity is negative at the beginning of disengagement, and drops to neutral at the end of disengagement. When a relief angle is added, the sear escapes before ever quite reaching neutral.-
Not really relative as if the hook tips are on the escape edge it can only be neutral as the escape edge and spot the hooks are on is one in the same. Negative will always be negative and positive will always be positive. Note the hammer hook face plane is not in line with the hammer pivot, the hook tip is comparable to a claw.
Originally Posted by
megafiddle
With my 87 degree sear face, the engagement polarity is very slightly negative at the beginning of disengagement, and very slightly positive at the end of disengagement. -
No it is positive, vice the frame and use a dial test indicator on the cocked hammer and you will see as soon as all the tolerances are used up the hammer further cocks, its just the geometry of this arrangement.
CAW
“If it ain't broke, don't fix it' is the slogan of the complacent, the arrogant or the scared. It's an excuse for inaction, a call to non-arms.” Colin Powell
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