Screw tightening

N

Nocturnal13

Joined
Apr 18, 2017
Messages
199
Hi guys.

You all will probably think I'm an idiot for making such a big deal out of this and you are probably right, but I do really have OCD and am struggling with getting over an issue.

Last year I stripped some threads on my Protech TR3 where the one screw only went in the aluminum handle about 3 threads because the pocket clip screw goes in the other side. Protech has helped me however since then I started to be very careful with screws going into aluminum as well as titanium.

After a while I heard people say any threads can strip if over tightened. So now any screws I tighten I will use 2 fingers to tighten but will always obsessively loosen it and tighten again thinking it's too tight or too loose. After disassembling a knife I will literaly loosen and tighten the screws for days afterwards being afraid I made it too tight or too loose.

Again you are probably right, I am retarded but I still can't help it. So I just wanted to hear how tight is too tight which can cause a problem and what is the standard way I can use not to overtighten or not tighten enough? How do you do it?

Sorry to bother you with this as I know it sounds stupid but it is starting to make knives more of a negative thing in my life than a positive thing and that sucks 'cause I love knives.

Thanks guys!
 
OCD is something you'll have to work on getting past. You can do it if you put your mind to it.

Until then, put a little dab of purple Loctite, (222 or 222 MS), on the threads, tighten until snug and leave 'em alone until you need to remove 'em again.
 
Don't beat yourself up for OCD. It's not a choice, it's an affliction that takes serious work to overcome or live with. So I totally agree with Loctite, I just want to add that if you have never used it before, color is EXTREMELY important. Red is essentially permanent, don't use it if you think you might want to disassemble or adjust. Blue is breakable if you want to take the screws out at a later date, particularly if you heat the screw with the tip of a soldering iron. Same with purple. So pay attention to the color of the tube to avoid future heartbreak. Or you can also raid somebody's nail polish clear coat--it works in a pinch, but make sure you put it back in the right place or you might be in for a few choice words.
 
Leave the screws alone.
Those screws are there for ASSEMBLY. There is little to no reason for you to take a knife apart.
More modern knives are damaged by disassembly than any other "maintenance" issue.
 
I hardly take any of my knives apart and I'm a mechanic by trade.
I tend to go with Mr DeShivs on this one.
The loctite and leave it is great advice as well.

I will add that properly cut threads in aluminum with full thread engagement isn't going to strip at the threads from over tightening such fine screws.
Titanium is so much more tough than MOST aluminum that it is a non issue.

Some quantifiers or is it qualifiers :
What is full engagement ? Five threads or the full thickness of the material.
I have seen screws that do not fully engage the liner or frame they are screwed into . . . on critical anchors such as pocket clips . . . on highly regarded brands here in the forum. I've nearly stripped them out but felt the thread beginning to go and stopped and put in a longer screw.

Is this where you are having trouble ? ^

Look before you give it that last bit of torque; is the screw going all the way to the other side of the liner or is there at least five threads of engagement ? If not light torque, locktite and prayer to your deity of choice is in order . . . or what I find to be more reliable : A longer screw.
People complain about screws going so far through the liner that they stick out the other side. I say better that than too short . . . every time ! ! !

Properly threaded what does that mean ? The screw just fits and doesn't have play and doesn't wobble about. Now if the liner is really thin then there is going to be bit of wobble and again you got to go light or change the design. I mod the heck out of my knives all the time. So far I have not had to threw bolt the thing or add a spacer to thread into to prevent screw thread damage.

If you really want to get into this you could get a tap or two, thread some material; first drilling it to the correct size and then thread some screws in and over torque them to see what happens.
I think you will find the fastener rounds out at the socket first and or the torx bit or allen twists / spirals. If the tool holds up you will snap the head off the screw. Oh look . . . the threads are still not stripped.

If they strip then there is a problem with the threads being cut with dull taps, the hole cut with dull or damaged bits and getting enlarged.
And finally that old bugga boo the cross threaded fastener.

Now ! ! !
That one will serve to demonstrate the strength of aluminum as a strong enough material to accept fasteners.
I have on many, many, many, many occasions removed a cross threaded fastener from an aluminum part. Even where the part had been cross threaded by a LEFT HAND fastener where a right hand fastener belonged or visyversy . . . I then run a correct threaded part in from the back side . . . often there is a thread there that has not been distorted thus molding the threads back into good enough shape to thread the fastener back in correctly (not cross threaded) . . .
Taken the torque PAST the recommended spec and the thing held up for years afterward. This was on a highly stressed area of the machine; any time it was in use the fastener was being given HELL !

That was a steel fastener in a heat treated aluminum part. A specific problem I see customers screw up and screw up badly (no pun intended) that I have to fix for them on regular basis.

Or :
you could put the screws in lightly and check them weekly to see if they have come loose.
Depends on how far you want to get into this. :)
 
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Well for female threads in softer material like aluminum, try to get a higher thread engagement. Even in steel you want at least 4 or 5 threads engaged. If you have more threads engaged it's tougher to strip the material.
 
I don't know if this will help, but screws don't strip from being too tight, they strip in the process of being over-torqued. So if it survived tightening it's OK, leave it alone!
 
Nocturnal13 said:
Hi guys.

You all will probably think I'm an idiot for making such a mccffddrrrr ig deal out of this and you are probably right, but I do really have OCD and am struggling with getting over an issue.

Last year I stripped some threads on my Protech TR3 where the one screw only went in the aluminum handle about 3 threads because the pocket clip screw goes in the other side. Protech has helped me however since then I started to be very careful with screws going into aluminum as well as titanium.

After a while I heard people say any threads can strip if over tightened. So now any screws I tighten I will use 2 fingers to tighten but will always obsessively loosen it and tighten again thinking it's too tight or too loose. After disassembling a knife I will literaly loosen and tighten the screws for days afterwards being afraid I made it too tight or too loose.

Again you are probably right, I am retarded but I still can't help it. So I just wanted to hear how tight is too tight which can cause a problem and what is the standard way I can use not to overtighten or not tighten enough? How do you do it?

Sorry to bother you with this as I know it sounds stupid but it is starting to make knives more of a negative thing in my life than a positive thing and that sucks 'cause I love knives.

Thanks guys!
Click to expand...

Yes screws that thread directly into titanium or aluminum tend to strip. The harder steel screw tends to damage the softer ti/al threads.

You’re actually bringing an even higher risk of stripping by overtightening and then loosening. The damage is done by overtightening. If you back off the screw abit after you already overtightened it that will do nothing to help.

The potential damage isn’t that a scew will sit in a knife being overtightened. Rather it is the act of overtightening in the first place that has the potential to cause damage.

What one should do is tighten until you feel resistence then stop.
 
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