How would you tighten these threads?

M

Makintrax73

H-M Supporter - Silver Member
H-M Supporter - Silver Member
Joined
Jun 20, 2022
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Thoughts on how to tighten threads? Made a pen with a screw in plunger to extend the ball point. Problem is I had to remake parts several times due to breakage at threaded areas, so I sized then a few thou loose to make tap and die work easier. Now I see I will probably loose this "nub" because it will work itself loose when not under tension (ball point retracted).

I thought maybe turn an inverted cone and try to squeeze it but I don't know if AL is malleable enough to do that....

20220713_095213.jpg

Yes I screwed up the knurl too. Live and learn.
 
thread locker?

I like this type of thread locker https://www.ebay.com/itm/224321895616 VibraTite VC3 I saw it on HM as an Ad a few years ago. I liked that you put it on let it dry, then you can use the part. So it becomes re-usable, vs a loc tite.. Both have their place. But that will keep the part from falling off.

BTW 2 years ago it was 8 and change... how times have changed.
 
woodchucker said:
thread locker?

I like this type of thread locker https://www.ebay.com/itm/224321895616 VibraTite VC3 I saw it on HM as an Ad a few years ago. I liked that you put it on let it dry, then you can use the part. So it becomes re-usable, vs a loc tite.. Both have their place. But that will keep the part from falling off.

BTW 2 years ago it was 8 and change... how times have changed.
Click to expand...

It needs to screw in and out so you can retract the tip of the pen. Not that it has to I guess, but that was the concept.
 
How about a slightly longer spring so the nub remains under load at all times?

Another thought is to machine a groove so you can put a little O ring in there to provide some friction to hold the nub in place. I dunno if the unthreaded groove stays inside the pen body but if it does you already may have what you need.

Fill the threads with epoxy and re-cut them?
 
woodchucker said:
That will allow it to.. It's not a permanent thread locker. Just something to prevent it from loosening on it's own.
Click to expand...
The product info says it's "5 or more times reusable" so it may not hold up long enough for his purposes. Not having used the stuff I don't know one way or the other.

I thought about suggesting _real_ heavy grease but then it would become a dirt magnet and probably not shirtpocket friendly.

Some folks have wrapped thread around threads to address a stripped-out thread situation.
 
homebrewed said:
How about a slightly longer spring so the nub remains under load at all times?

Another thought is to machine a groove so you can put a little O ring in there to provide some friction to hold the nub in place. I dunno if the unthreaded groove stays inside the pen body but if it does you already may have what you need.

Fill the threads with epoxy and re-cut them?
Click to expand...

That gives me another idea.....maybe remove the nylock part of a nylok nut and bore the end out and glue it in the end of the pen body.
 
That VC3 stuff looks pretty cool but as homebrewed pointed out it says it's good for 5 or more times.
 
Makintrax73 said:
That gives me another idea.....maybe remove the nylock part of a nylok nut and bore the end out and glue it in the end of the pen body.
Click to expand...
You don't need to buy a nylok nut for that if you have some string trimmer material on hand. It's designed to be pretty tough, considering what it's called on to do. Gluing it in might be difficult, but I think it can be melted. IIRC nylon can be 3D printed if you've got the right printer, so it HAS to melt if that's the case.

And here's yet another thought. Douse the nub with mold release then coat the threads with epoxy. Screw it into the pen body and let it cure, then back the nub out. You should have some much tighter threads....if, that is, you can get the nub to unscrew!
 
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