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Printed holes not big enough for screws?  

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Gordon Krum
(@gordon-krum)
Active Member
Printed holes not big enough for screws?

When assembling the enclosure, my second, I am finding that printed holes are not big enough for the screws. The holes on the feet were tight. The holes in the PSU locks are too small to accept the screw. I have PETG but don’t have ABS for my 3S+ printer. Should I try to print in ABS? Wait for replacements? Just force the start of the screw? Any Advice. I’m wondering if this issue is going to repeat in other parts.

Respondido : 23/09/2024 9:21 pm
_KaszpiR_
(@_kaszpir_)
Honorable Member
RE:

Force screw in the bolt into the plastic. You can use heat gun to heat up a bit the plastic so it expands more easily.

Another option is to get one screw and use a filer to file out about 2mm of the screw end on two sides, thus when force screwing it will remove excessive amount of plastic. Some screws have it done in factory, and are named self-drilling screws.

See my GitHub and printables.com for some 3d stuff that you may like.

Respondido : 23/09/2024 10:42 pm
Gordon Krum
(@gordon-krum)
Active Member
Topic starter answered:
RE: Printed holes not big enough for screws?

Thank you! I’m going to use the file to make a self starting screw method. These locks need to move and to do so need to be a little loose on the frame. Yet they need to extra tight on the screw itself.  Thanks again:)

Respondido : 23/09/2024 11:56 pm
_KaszpiR_
(@_kaszpir_)
Honorable Member
RE:

One more thing:
-  get one screw
- screw it in to the plastic part
- heat it up to something like 230C or less (if it is PETG) by using soldering iron with temperature control for 30s so it melts the plastic around the threads
- remove the soldering iron and let it cool down

If you control time/temperature you will get a well melted plastic around the bolt threads.

Try on some new part that is displosable, not sure if it would work and not melt+merge with the nut making it real mess which rbeaks plastic when unscrewing 😀 

See my GitHub and printables.com for some 3d stuff that you may like.

Respondido : 24/09/2024 7:00 pm
Gordon Krum
(@gordon-krum)
Active Member
Topic starter answered:
RE: Printed holes not big enough for screws?

Thanks for the info. I’m sure that I’ll using heat to solve some issue someday:)

I realized that a self tapping screw has a tapered end with about 1/4 of the tip cut out. After some experiments I filled all 4 sides down to about 3 three threads keeping the cut flat and steep. This left me with a little square  on the tip of a little tapper. I took the sharpness off of the corners of the little square with a light file stroke. It’s a micro tap as in threading tap & die.

This worked. I had the screw in a vise grip pliers to file it. I put the Lock in another locking pliers. Then I screwed the Lock down onto the screw. It took a lot of pressure both pushing the screw In and Turing it too. I ran the screw halfway in before it caught the hole and ran true. Oddly, just before the screw ran true the Lock gave it’s biggest wobble?

My best………… PRUSA  ROCKS! ! !

Respondido : 24/09/2024 7:29 pm
_KaszpiR_
(@_kaszpir_)
Honorable Member
RE: Printed holes not big enough for screws?

You could also try to use a hand drill with the proper diameter just slightly lower than the thread diameter 😉

But heating is usually better because it expands in all directions and even placing it on the hotbed with 100C to hest it up for about 5min should be enough - just remember to use gloves.

See my GitHub and printables.com for some 3d stuff that you may like.

Respondido : 25/09/2024 7:22 am
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