ptonsparky
Tom
- Occupation
- EC - retired
Anyone with a idea to the max torque for a 1/4 x 20 thread rolling screw or bolt? Goes into a Seimens distribution panelboard.
thread roller
- Thread starter ptonsparky
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gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
120907-1622 EDT
What is a thread rolling screw? Is this a self tapping screw that does not cut the material, but just reforms the material in the hole it is going into? In other words the equivalent function of a form tap.
I have done form tapping, but in a machine and I have no idea of the torque. The tap hole has to be larger than used with a cutting tap because the material is being cold formed into the valleys of the tap. I do not hand form tap because of the higher torque than a cutting tap and the lower rigidity of hand holding compared to a machine.
The torque required will be a function of the material hardness and coefficient of friction. It is possible to form tap in prehard 4140 steel. This is a roughly a Rockwell 30 very tough high alloy steel.
.
What is a thread rolling screw? Is this a self tapping screw that does not cut the material, but just reforms the material in the hole it is going into? In other words the equivalent function of a form tap.
I have done form tapping, but in a machine and I have no idea of the torque. The tap hole has to be larger than used with a cutting tap because the material is being cold formed into the valleys of the tap. I do not hand form tap because of the higher torque than a cutting tap and the lower rigidity of hand holding compared to a machine.
The torque required will be a function of the material hardness and coefficient of friction. It is possible to form tap in prehard 4140 steel. This is a roughly a Rockwell 30 very tough high alloy steel.
.
cadpoint
Senior Member
- Location
- Durham, NC
The answer is on the web with your favorite search engine, using "max torque for a 1/4 x 20 thread"
Depending on the exact spec of the metal that composes the bolt it can be anywhere from
60 in-lbs to almost 78 in-lbs.
Quoting from this page http://www.engineersedge.com/torque_table_sae.htm
From this search Google
I'm going to assume that all nuts or plates are machine bored. There are formula's to determine more things, I made no assumption on how many threads are engaged to make the in-lb statement.
Depending on the exact spec of the metal that composes the bolt it can be anywhere from
60 in-lbs to almost 78 in-lbs.
Quoting from this page http://www.engineersedge.com/torque_table_sae.htm
From this search Google
I'm going to assume that all nuts or plates are machine bored. There are formula's to determine more things, I made no assumption on how many threads are engaged to make the in-lb statement.
ptonsparky
Tom
- Occupation
- EC - retired
That is close 75+- k found for SS.
Going into copper buss bars and yes they roll the thread vs cutting them. We had to settle for something close.
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