This is an Excel spreadsheet that calculates the buckling force on the bottom rod due to flow through the plunger. The spreadsheet is protected so that only the data input cells can be changed. The results do not include friction in the pump from any other source save flow through the plunger. So, the results represent the minimum buckling force acting on the bottom rod. A liquid viscosity calculator is on the bottom of the spreadsheet that can be used to estimate the liquid viscosity. A table on the bottom shows the force necessary to buckle a rod of a given diameter. If the buckling force is more than the critical force necessary to buckle the bottom rod, sinker bars should be used to offset the buckling force as described in Chapter 7.