What torque settings for accessory screws.

As a newish teacher I am trying to get students to fix things with the correct amount of torque.

Tightening brass screws like they are wheel nuts does not give materials much of a lifespan.

So I bought a couple of torque screwdrivers, so they can quickly get a feel for how tight things should be.

However now I look at data sheets I can't seem to find Torque info for anything smaller than a a miniature circuit breaker.

The data sheets now often include other everyday information like Altitude.

Does anyone have some guidance for smaller brass screw torques, or know of a manufacturer that publishes such data?

Parents
  • I agree with the above posts. Where items need to be set to critical torques, there are a whole set of instructions for the assembly, everything to thread lubrication with a specific lubricant, or even met5iculous cleaning of both parts, and certainly small screws will very rarely have a torque specification. The "modern" way to set torques is mpre complex, first the bolt is torqued to a fairly low value, then a higher one and then a further rotation of so many degrees is applied. This technique does need a reasonable length of bolt which is not engaged in a thread to stretch (actually to be like a very strong spring) but is much more reproducible. I am not a great fan of torque settings themselves, it depends far too much on everything else being specified as well, particularly the conductor size and makeup wires, and breaking brass screws is a serious hazard. Note that many screws are now made of steel for this reason! It is a matter of practice, as tight as "is reasonable" for the screw size works quite well. learning with a steel tapped bar and a selection of small brass screws would be an interesting exercise.

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  • I agree with the above posts. Where items need to be set to critical torques, there are a whole set of instructions for the assembly, everything to thread lubrication with a specific lubricant, or even met5iculous cleaning of both parts, and certainly small screws will very rarely have a torque specification. The "modern" way to set torques is mpre complex, first the bolt is torqued to a fairly low value, then a higher one and then a further rotation of so many degrees is applied. This technique does need a reasonable length of bolt which is not engaged in a thread to stretch (actually to be like a very strong spring) but is much more reproducible. I am not a great fan of torque settings themselves, it depends far too much on everything else being specified as well, particularly the conductor size and makeup wires, and breaking brass screws is a serious hazard. Note that many screws are now made of steel for this reason! It is a matter of practice, as tight as "is reasonable" for the screw size works quite well. learning with a steel tapped bar and a selection of small brass screws would be an interesting exercise.

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