VOGONS


First post, by user33331

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Hello
I have broken so many fragile old plastic threads: screw diameter sizes 2,3,4(mm).
Threads either cracked or weared out due to multiple openings causing screws to spin.
So I must be doing something wrong.

Do you use those small torque hand screwdrivers(unmotorized) ?
Can you recommend a certain brand ?

What torque Nm do you use for 2,3 and 4mm diameter screws ?

- Do you put some specific rejuvenating grease or oil to old plastic thread holes first ?

What to do when threads crack ?

- Any plastic thread hole healers ? To seal the cracks and rethicken the thread ?
- Quick\super glues as Loctite just cracks open again due to pressure.(So no to quick/super glues)
- Teflon=plumber's tape sometimes helps if the hole is large.

Reply 1 of 2, by yawetaG

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When putting screws back in:
- First turn counterclockwise until the screw drops slightly. This means it has found the old thread.
- Don't over-tighten self-tapping screws. When they start going in more difficultly, they are in far enough.

As for aging plastics cracking, not much can be done about it except storing things outside of sunlight/high temperatures/high moisture.

Reply 2 of 2, by user33331

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Are there any torque recommendations for screws used in plastic parts to avoid over tightening ?

Screws that I usually face are fine threaded "thread forming screws" and not those coarse wood screw style "self-tapping screws".

Small D=2mm and 2.5mm screws seem easy to over tighten. Hope to buy a torque screwdriver to solve the problem.