I have been watching YouTube videos again as I am highly interested in creating and checking and improving flat surfaces. And a question that has been bothering me for a while came up again.
The classic repeat-o-meter design features a base with three feet and an arm that is attached to that base with a "hinge" that is made of a thin section of metal. That arm has a fourth foot on the bottom, near the end away from the hinge and a highly sensitive DI has it's tip resting on the top of the hinged arm, approximately above that fourth foot.
What I can not figure out is why do they use that arm? It seems to me that the arm simply transmits the movement from the foot on the bottom to the DI's tip on it's top in a one-to-one fashion. There is no amplification of the amount of movement. The foot on the bottom is very much like the tip on the DI and even if it weren't, every DI that I have from the cheapest to the most expensive and most sensitive all have changeable tips. So if a different type of tip is needed, it would be easy to just buy or make one and screw it on.
There is a fine adjustment that can raise or lower the arm (sic: it actually moves the DI) to zero the meter or zero the instrument, but it would seem that could just as well move the arm that the DI is attached to and accomplish the same thing.
Then there is usually a mechanical stop that limits the downward motion of the arm, but that is just to prevent the hinge from being bent beyond it's elastic limit.
So, can anyone tell me why they use that arm? There must be some logical reason.
The classic repeat-o-meter design features a base with three feet and an arm that is attached to that base with a "hinge" that is made of a thin section of metal. That arm has a fourth foot on the bottom, near the end away from the hinge and a highly sensitive DI has it's tip resting on the top of the hinged arm, approximately above that fourth foot.
What I can not figure out is why do they use that arm? It seems to me that the arm simply transmits the movement from the foot on the bottom to the DI's tip on it's top in a one-to-one fashion. There is no amplification of the amount of movement. The foot on the bottom is very much like the tip on the DI and even if it weren't, every DI that I have from the cheapest to the most expensive and most sensitive all have changeable tips. So if a different type of tip is needed, it would be easy to just buy or make one and screw it on.
There is a fine adjustment that can raise or lower the arm (sic: it actually moves the DI) to zero the meter or zero the instrument, but it would seem that could just as well move the arm that the DI is attached to and accomplish the same thing.
Then there is usually a mechanical stop that limits the downward motion of the arm, but that is just to prevent the hinge from being bent beyond it's elastic limit.
So, can anyone tell me why they use that arm? There must be some logical reason.
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