Torque

You forgot to tell us (among other things) the plate material. SS? tungsten? polystyrene? zinc? It makes a difference, you know!

The material nor any lubrication doesn't matter unless one wants the screw to be installed or extracted. I realize that this seems like an assumable concern but cutting threads will require more torque than extraction. Then a galling incident happens. Then there is the head tightening process and the undesired bolt damaging torque level.

While it might be an interesting class assignment to tell a group of mechanical engineering students to predict the required torque (show all work) I see no other value in doing this analysis. Many manufacturers will provide this information from measured results if one needs to know.

I disagree that the material or lubricants do not matter.

There is a significant difference in torque required to tap soft materials verses harder materials.

There is also a significant difference in allowable torque when installing screws or bolts into soft or hard materials.

Using standard torque chart values that do not take into consideration the hardness or softness of the material when installing self-tapping or threaded fasteners will result in damage or failure of the threads and failure of the fastener and/or the material.

Example: You cannot use the same torque value on a grade 8 bolt when installing it into aluminum as you can when installing a grade 8 bolt into hardened steel. The same applies when soft materials are being sandwiched between harder materials.

Aluminum "Isophase" electrical buss conductors utilize threaded buss connector fasteners that are grade 8 and if the fastener bolts are tightened to standard torque chart values they will be pulled through the aluminum causing serious damage to the buss.

Read my comment again. The material matters only if one will be moving the screw. Our OP did not even say if they will be installing or removing this screw. We know so very little about this screw that we do not even know if it is supposed to move. That is my point, not that the material is irrelevant to tightening, self tapping, extracting or stripping this screw. There are at least four different modes of operation this screw might be in that require torque to be applied but from the information provided we do not even know if torque will be needed at all.

A phone call to the manufacturer is all it takes.

1. I Googled this "torque for my M6 self taping screw"
2. and got this:
3. www.fasnetdirect.com/refguide/Metthreadroll.pdf
METRIC FASTENERS self-Tapping screws. METRIC - TRIlobulaR ThREad RollIng SCREwS. DIN. 7500-1. Nominal. Size &. Thread. Pitch. C. B. P. Test Plate.
4. Learn how to GOOGLE!

Your question is not clear.

Do you mean insertion/tightening torque?

Thread pull-out/failure torque.

Twist-out torque?

Tensile failure torque?

Yes, all of this and many other questions posed here can be answered by a simple search.

Try it next time.

You have forgotten to ask:

What is the color of the test plate?
Should the torque be quantified in henway or duckdo per radian?

Correct. The test plate can take on many hues. Or hews. Or, even Yew if wood.

It could be steely colored, aluminumy colored or some other flavor.

I prefer henway as it gives a cleaner result.

How much does a henway?

Does your response mean you already know the answer to:

What's a duckdo?

You take these, please.

My shift ends in 5 minutes.

Talk to the people who make the screw.

I don't rate that answer as off topic at all.

There are so many possible variables to the answer that a query to the manufacturer is the only correct course of action.

Most manufacturers will readily state that their screws are some special alloy composition, but few will give out particulars of that alloy. So a torque chart for one particular alloy may be way off target for the actual one being used.

Lyn is right - Talk to the people who make the screw.

A few seemingly contradictory views have been expressed, and I believe that both are correct in their ways.

The Material type, lubrication and thickness is important if we are talking about thread forming torque, ie. the torque required to cut the thread, as that will vary with the density and thickness of what is being threaded. That data can often be obtained from the manufacturer. Thread pitch will also affect required cutting torque.

The material, lubrication and thickness is unimportant if we are talking about the failure torque value of the screw, and this data will definitely need to be obtained from the manufacturer.

It's also important to note that other torque values such as "assembly torque" and "first removal torque" may need to be considered.

Hole diameter also has a bearing as the degree of thread engagement will be less with an over size hole. For instance, in your case, the 6mm screw (with say a 1mm pitch) in a 5.5 mm hole will give a thread engagement of around 75% whereas a 5.35 mm (#4 drill) hole will produce 100% thread engagement. Obviously, more forming torque will be required for the deeper cut.

Assuming that your material is mild steel, then reasonable figures with the 5.5 mm pilot hole may be 1.5 N m forming torque - 0.4 N m First removal torque - 4 N m assembly torque.

Personally, I think these figures are way too low for satisfactory performance and you should consider reducing the pilot hole size.

Wow.

Perhaps a review of ISO 965 is in order, as well as a review of a tap/drill chart from just about any reasonable source.

http://www.physics.ncsu.edu/pearl/Tap_Drill_Chart.html

I'm not sure of your point here.

Remember that we are talking about a self tapping screw where the pilot hole size will need to be slightly larger than it would for a standard threading tap.

I would normally use a number 8 or 5 mm drill for a 6 x 1 mm thread, but larger for a self tapper.

A 5.5 mm hole will produce a pretty ordinary fit with only 2 full threads at 75% engagement in 2.5 mm thick material.

I would expect that most manufacturer's specs would concur with that.

What does that guy on Mythbusters say... "I reject your reality, and substitute my own."

Yeah, looks like I'm answering the wrong question.

Looks like DIN 7500 is in play here.

5.46-5.4 mm hole max-min is specified for 2.5mm material, max torque to drive is listed as 8 Nm by these guys:

http://www.fasnetdirect.com/refguide/Metthreadroll.pdf

While not certain. I would suspect the information given in the link posted in #22 is an average of direct measure.

As pointed out in this discussion, the parent material will have an impact as will the condition and size of the hole (pierced and deformed, punched, drilled (a trilobular form itself) rusty/corroded...).

You are really quite helpless, aren't you!

Read these:

These FIRST:

5 Ways to Ask a Question Intelligently - wikiHow

How to Ask Intelligent Questions | eHow

Then this:

TAPTITE II - REMINC & CONTI

If you think you provided sufficient information for an informed answer, you may have come to the wrong place.

Being a good poster you should know that those who hid behind the curtain of anonymity have no right to criticize anybody!

There were any number of requests for meaningful information from the OP, all without any worthwhile response!!!!!!!!!

Try helping the hapless requester of information next time instead of spouting useless drivel.

Yes exactly try helping rather than criticize, but your comments are nearly the same every time, mostly negative. I dropped out of the post several years ago because of these negative answers. As I hinted to: are there any engineers that can answer questions and narrow down what the problem is. As far as being anonymous, what is the difference when the truth is revealed.

Hi

i wanted to know the torque for my M6 self taping screw having Trilobular thread rolling screw. Some useful Dimension i have given below

Major Diameter=6mm

test plate thickness=2.5

hole diameter = 5.50

I have never heard of a "self taping screw". It sounds like it involves motion detectors and cameras so I will opt not to comment.

Good how you read things literally. So many people cannot spell and have really very little grasp of the English language these days. It pains me (a little anyway) when I read posts where spelling and grammar are out the window. If poster has english as a second language, I can partially understand, but for anyone that has english as their native language, no excuse.