# How many pounds does everyone think it will take to fail the disco pinning ??

Joined: April 28th, 2010, 12:23 am
Last edited by robnewyork on February 11th, 2012, 5:22 am, edited 1 time in total.

Joined: September 23rd, 2002, 6:16 pm
what does the math say about it?

I may get a chance to do it this weekend....

Joined: April 28th, 2010, 12:23 am
Last edited by robnewyork on February 11th, 2012, 6:49 am, edited 1 time in total.

Joined: June 15th, 2004, 11:49 pm

Joined: April 28th, 2010, 12:23 am
Last edited by robnewyork on February 11th, 2012, 2:42 pm, edited 1 time in total.

Joined: September 25th, 2006, 2:19 pm
This is an electricians tool which can shear off screws to proper length stop I do not have one but have used one stop I believe it will shear a screw size up to 10-32 stop Anyway, the force to shear a 10-32 with such tool is not all that great as even a scrawny caveman can to it stop

Soooo, IF I had one of these tools, I would extend the handles about 18 inches by sliding two lengths of tubing over them stop To determine the force required to shear the 10-32, I would place one handle on a bathroom scale and push down on the other handle so as to get a scale reading when the screw shears stop Then I would back figure the MA to determine the actual shear force stop

Joined: April 28th, 2010, 12:23 am

Joined: November 22nd, 2002, 10:41 pm
This is an electricians tool which can shear off screws to proper length stop I do not have one but have used one stop I believe it will shear a screw size up to 10-32 stop Anyway, the force to shear a 10-32 with such tool is not all that great as even a scrawny caveman can to it stop

Soooo, IF I had one of these tools, I would extend the handles about 18 inches by sliding two lengths of tubing over them stop To determine the force required to shear the 10-32, I would place one handle on a bathroom scale and push down on the other handle so as to get a scale reading when the screw shears stop Then I would back figure the MA to determine the actual shear force stop
Gun fastening, the more meaningless the test becomes. A huge part of the ultimate shear limit of an assembly is the actual details of the fastening parameters, such as tube/body clearance, thread condition (fit/finish) screw quality, preload torque from factory, hole clearance/alignment etc.

I suspect any test not using an actual production line gun is going to give only rough approximations, and a test such as use of a bolt cutting tool to measure shear forces only tests bolt cutting tools and the screws used in the test.

One may just as well simply look up the shear limits of 10-32 screws, since its easily found online. That said, the range varies around 100%, based on screw alloy, type etc.

Joined: September 25th, 2006, 2:19 pm
Of course that would be a good start. BUT. I have searched and found no real commitments insofaras a chart.

Probably no hard and fast formula for the reasons that you explain. Most shear applications really need to be emperically determined.

Although I did once come upon a "rule of thumb" for shear which was a perentage of tensile. But I cannot seem to get back to that page on the net.

Joined: April 28th, 2010, 12:23 am
Gun fastening, the more meaningless the test becomes. A huge part of the ultimate shear limit of an assembly is the actual details of the fastening parameters, such as tube/body clearance, thread condition (fit/finish) screw quality, preload torque from factory, hole clearance/alignment etc.

I suspect any test not using an actual production line gun is going to give only rough approximations, and a test such as use of a bolt cutting tool to measure shear forces only tests bolt cutting tools and the screws used in the test.

One may just as well simply look up the shear limits of 10-32 screws, since its easily found online. That said, the range varies around 100%, based on screw alloy, type etc.