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Volhout

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Joined: 05/03/2018
Location: Netherlands
Posts: 6151

Posted: 08:21am 01 Oct 2026

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A very simple solution (that is virtually impossible with drilling) is to screw the self threading screw into a square hole. A 3D printer can create square holes easily, and it is the simplest geometrical form that allows disposal of scraped off material.

Volhout

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Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 9166

Posted: 09:53am 01 Oct 2026

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That's a good idea. I might give that a try.

The little brass inserts hardly break the bank though. About £2 for 50 M3 or 100 M2.5. The attachment for a T12 iron was about £4.60. That deals with all sizes from M2 to M6. They are a much better idea for holding case halves together.

Mick

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Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1138

Posted: 08:22am 03 Oct 2026

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zeitfest said There are "heated brass thread inserts" which are said to insert into
plastic cases and have a strong thread (a soldering iron heats the the insert
and it bonds in place), don't know if they are ok.

I didn't know about these.
For bigger stuff, I've been using helical ones used in woodwork. They were sort of OK in part.
I ordered a box of assorted heated ones which arrived today. They look much better & should work better assuming I can fit them properly. The 2mm ones look like fun.
Thanks for that to others for their comments

Brian

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Mixtel90

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Posted: 09:48am 03 Oct 2026

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Be careful with the inserts. There are single and double ended ones. The single ended ones are a simple tube at the end that enters the plastic and these are the ones we want. The double ended ones have knurled collars at both ends and are intended for injection moulding. I'm told that they will work but aren't as good, being difficult to insert and having less grip. I've not verified this.

Mick

Zilog Inside! nascom.info for Nascom & Gemini

Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1138

Posted: 11:09am 03 Oct 2026

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Thanks Mick

The ones I got are labeled as a Hot Melt Nut Kit & are single ended with the Chevron pattern on the top section a small plain section on the bottom. They came with the insertion tool & adaptors (which will be the first things to lose)

Brian

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Mixtel90

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Location: United Kingdom
Posts: 9166

Posted: 11:18am 03 Oct 2026

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Yeah... The adapters are a bit small. :) They are made so that they can roll to inaccessible places too.

I bet there's a 3D printable holder for them somewhere.

Mick

Zilog Inside! nascom.info for Nascom & Gemini

Chopperp

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Location: Australia
Posts: 1138

Posted: 11:49am 03 Oct 2026

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Mixtel90 said I bet there's a 3D printable holder for them somewhere.

Now that's an idea.
I made one for a set of wad punches many years ago so I wouldn't lose them. Now I can't find it or the punches.

ChopperP

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