Torque screw drivers

Status
Not open for further replies.
wwhitney said:
Could someone explain how overtorquing a device screw can cause a connection failure? I understand that you can overtorque it enough to cause the screw to fail or strip out, but that would be obvious at the time of making the connection.

Thanks, Wayne
Click to expand...

You can crush the wire so severly it distorts it and the connection between the conductor and the lug/screw can be compromised. On a simple device such as a switch or receptacle, you can physically break the parts.
 
wwhitney said:
Could someone explain how overtorquing a device screw can cause a connection failure? I understand that you can overtorque it enough to cause the screw to fail or strip out, but that would be obvious at the time of making the connection.

Thanks, Wayne
Click to expand...

I have seen a few lugs broken in half by over torquing and a couple (Murray) that broke before the specified torque was even met.
There is a local AHJ that requires you to have the T-wrench in hand for final at the panels, I personally find this idiotic because if you have ever torqued large wire then come back later and torqued it again (and I don't believe this is required) it will tighten more. All the inspector will see is the wire is not loose there is no guarantee that it is not over torqued.
 
acrwc10 said:
I have seen a few lugs broken in half by over torquing and a couple (Murray) that broke before the specified torque was even met.
There is a local AHJ that requires you to have the T-wrench in hand for final at the panels, I personally find this idiotic because if you have ever torqued large wire then come back later and torqued it again (and I don't believe this is required) it will tighten more. All the inspector will see is the wire is not loose there is no guarantee that it is not over torqued.
Click to expand...
A T-wrench but not a torque wrench? Sure, I can see that happening. That's the point of using a torque wrench, it slips or releases at the point that you wouldn't! It tightens to the exact same point every time, do you??
 
wptski said:
A T-wrench but not a torque wrench? Sure, I can see that happening. That's the point of using a torque wrench, it slips or releases at the point that you wouldn't! It tightens to the exact same point every time, do you??
Click to expand...

NO I meant torque wrench when I "abbreviated" to T-wrench.
So let me say this again, I have seen lugs break BEFORE reaching maximum torque as "specified by the manufacturer" this happened more then once in Murray panels. I don't know if it was an incorrect spec. from the manufacturer or the wrong lug was installed in the panel , either way it busted before it should have, Well before !
 
Two questions for all you torque-wrench and -screwdriver users now:

1. How many of you dial your tools back to zero (or lowest setting) when you're done using them?

2. How many of you have your wrenches & screwdrives calibrated periodically?
 
480sparky said:
Two questions for all you torque-wrench and -screwdriver users now:

1. How many of you dial your tools back to zero (or lowest setting) when you're done using them?

2. How many of you have your wrenches & screwdrives calibrated periodically?
Click to expand...

every time.
 
480sparky said:
So when you torque a lug, you must reset the dial every time?
Click to expand...

Sorry Ken, I misunderstood the question. I thought you were saying the wrench needs to be set to zero between operations.

Yes I zero mine out for storage. Never understood why, but thats in the instructions for both of mine.
 
480sparky said:
Two questions for all you torque-wrench and -screwdriver users now:

1. How many of you dial your tools back to zero (or lowest setting) when you're done using them?

2. How many of you have your wrenches & screwdrives calibrated periodically?
Click to expand...
I dial back every time. A 3/8" drive Proto that goes down to 10 lb/in which nobody makes anymore was calibrated about a year ago, only because it wouldn't release at 15 lb/in and I sent it in. My 1/2" drive Craftsman, never!
 
acrwc10 said:
NO I meant torque wrench when I "abbreviated" to T-wrench.
So let me say this again, I have seen lugs break BEFORE reaching maximum torque as "specified by the manufacturer" this happened more then once in Murray panels. I don't know if it was an incorrect spec. from the manufacturer or the wrong lug was installed in the panel , either way it busted before it should have, Well before !
Click to expand...
I shall have to experiment with that a bit.

I hope that your using a constant steady pressure and no jerky motion when using a torque wrench? If you jerk on it, it will always move again. When your torquing something with a dozen bolts at over 100 lb/ft, it's tiring to do it correctly!
 
wptski said:
I shall have to experiment with that a bit.

I hope that your using a constant steady pressure and no jerky motion when using a torque wrench? If you jerk on it, it will always move again. When your torquing something with a dozen bolts at over 100 lb/ft, it's tiring to do it correctly!
Click to expand...

Hey I'm not heading up a team of mules, just tightening a lug or two. :D
 
wptski said:
When your torquing something with a dozen bolts at over 100 lb/ft, it's tiring to do it correctly!
Click to expand...

I used to have to torque a large bearing (slewing ring really) 400 ft pounds and at least 50 bolts I bet closer to 75. The wrench was almost 4' long but the work had to be done from a bucket truck.
 
iwire said:
I used to have to torque a large bearing (slewing ring really) 400 ft pounds and at least 50 bolts I bet closer to 75. The wrench was almost 4' long but the work had to be done from a bucket truck.
Click to expand...

I'll bet that got the bucket swaying back and forth.
 
Status
Not open for further replies.
Top