Bolster Rivet Press

The goal of this project is to create a test fixture and associated calibration methods to measure the required force to optimally compress and seat rivets in the production of knives. Also to Provide assistance to both designers and machine operators that improves the quality and consistency across a spectrum of knife families.

Problem Statement
Design a force calibration tool comprised of a load cell and digital display to aid in the calibration of rivet presses in operation

Background Information
Buck Knives currently produces several common knife models that are held together with bolster rivets. Last year, Buck Knives supported a senior design project where the team was tasked with creating a machine that inserts pins into three locations in the knife. This year we started out re-creating a bolster rivet press to press these pins to hold the knife together. Initially Buck Knives thought they wanted there old bolster rivet press for there 110 and 112 models replaced. Later they realized that having precise force measurements and a calibration device would be more beneficial. The calibration device would not be for the one press but all that they currently are using for manufacturing knives.

 Knife Models 

Design Specifications

 * Device is of universal design
 * Fits all presses in operation (required)
 * Compatible with a standard laptop (desired)
 * Produces accurate readings
 * Measure force (required)
 * Measure displacement (desired)
 * Control load w/manual actuation
 * Readouts
 * Built in display or
 * Displays on laptop (desired)

Completed Task List

 * Data analysis of required force on pressing of single rivet
 * Comparative analysis between nickel and brass knife models
 * Analysis of addition of compliant materials during pressing process
 * Research on load cells and associated equipment
 * Purchasing of load cell and associated equipment
 * Assembly and testing of portable force calibration tool
 * Design and fabrication of portable enclosure for calibration equipment
 * Detailed report on rivet analysis and material findings

Deliverables

 * A detailed write up and report on our analysis and findings pertaining to the compression of a single rivet taking into account the different materials (brass and nickel) and the addition of the compliant material to the pressing process.
 * A force calibration tool comprised of a load cell and digital display allowing for the reading of a specific

SATEC Testing


Before starting testing we determined there were four critical conditions that had to be met. The pins had to be press hard enough to hold the knife together well and to keep the knife blade stable but not pressed to the point that it will hinder the knife's ability to open and close. Also the knife could not be physically damaged by the pressing process. Though testing with the satec machine we have discovered the optimal force to be used one each rivet is in the range of 2000-2200lbf. In this optimal range all four conditions and were all satisfied.

Testing Apparatus
This testing apparatus was designed and built to mimic the hydraulic presses being used by Buck Knives on their shop floor. This device uses the same anvils that all the presses at Buck Knives use. Using this device in the SATEC machine, data was produced and collected to determine the optimal force it takes to properly seat a rivet.

Charts
 Click Charts for Larger View 

Sponsor
This Project is supported by

Buck Knives

660 S. Lochsa Street

Post Falls, ID 83854-5200

Design Documents
 Test Apparatus: Drawing Package 





 Top and Bottom Plates: Drawing Package