At no time have you stated that when you measured one pound on the prony brake that the circuit yielded a voltage that can be verified using Ohms Law and Your statement of the passive resistance of the sensor out of the circuit on an ohmeter as 60k ohms.
By Ohms Law you should be able to obtain the correct voltage (about 2.5 V or 520 ANALOG COUNTS) . Nothing you have have stated comes anywhere close. Your statement that 50 counts or so was ok makes no sense. The math is very clear cut with Ohms
Law. You should be reading about 2.5V using the Fritzing circuit setup with a 1 Meg resistor. You don't have anything near that.
Nothing you have said indicates that you can obtain a correct reading at 1 lb force on the Prony brake. Show me your data that proves your circuit is working (or ever worked). I don't see it unless you have not been completely forth-coming which I have no reason to suspect. Put 1 lb of force on there and take a photo of a multimeter reading approx 2.5V AT THE ARDUINO ANALOG INPUT PIN and I will be convinced. Otherwise, the way I see it , you got nothing.. (that works)
Also, post your code so we can see what your doing.
BTW- I caught a minor mistake I made on my last post with the calculations and I corrected it.