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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Hand tight switch barrel accuracy?
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<blockquote data-quote="ntsqd" data-source="post: 2005004" data-attributes="member: 93138"><p>Lubrication of the thread has a HUGE effect on the result. Have a look at this chart: <a href="https://www.portlandbolt.com/technical/bolt-torque-chart/" target="_blank">https://www.portlandbolt.com/technical/bolt-torque-chart/</a> and notice the different torque requirements needed to achieve the same tensile loading in the bolt. That is just the first such chart that I found, there are many like that.</p><p></p><p>In highly critical assemblies even a torque spec is not good enough. On fasteners like racing connecting rod bolts best practice is to measure how much the fastener stretches as the nut is tightened. Their "torque spec" is related as being ".009 stretch" and similar. Some German engines were the early adopters of torque to some low setting plus an angular measurement of further thread rotation. So a spec for one of those bolts would be "23 ft-lbs + 45°"</p><p></p><p>I don't see the former being terribly practical in firearms, but the latter method has some merit & may be worth some investigation.</p></blockquote><p></p>
[QUOTE="ntsqd, post: 2005004, member: 93138"] Lubrication of the thread has a HUGE effect on the result. Have a look at this chart: [URL]https://www.portlandbolt.com/technical/bolt-torque-chart/[/URL] and notice the different torque requirements needed to achieve the same tensile loading in the bolt. That is just the first such chart that I found, there are many like that. In highly critical assemblies even a torque spec is not good enough. On fasteners like racing connecting rod bolts best practice is to measure how much the fastener stretches as the nut is tightened. Their "torque spec" is related as being ".009 stretch" and similar. Some German engines were the early adopters of torque to some low setting plus an angular measurement of further thread rotation. So a spec for one of those bolts would be "23 ft-lbs + 45°" I don't see the former being terribly practical in firearms, but the latter method has some merit & may be worth some investigation. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
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Hand tight switch barrel accuracy?
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