Originally posted by xma:
Although no engineer, I would advise against making the adapter too long. Under the simple principles of leverage, any shearing force would transfer down the added length of the adapter to translate into easier bending and increasing the potential for weakness.
i'm not sure i agree.
consider this- the broadhead is the part encountering the resistance and it is being pushed along by the center of gravity of the arrow (the balance point) which is behind the broadhead. the closer you can get the back of the insert to the balance point the better. this gives the center of gravity less leverage against the back of the insert.
the closer the load (broadhead) is to the fulcrum (back of insert) the easier it is for the force (arrow center of gravity) to act upon the load. and if the fulcrum is weaker than the load it gives way, which is what i want to avoid. i suspect that breakage at the back of the insert would be significantly reduced if the back of the insert was behind the balance point. though i'm not sure that is practical.