Best fasteners for ABS cases?

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ajohnsonlaird
Posts: 47
Joined: Sat Nov 23, 2013 6:35 am

Best fasteners for ABS cases?

Post by ajohnsonlaird » Tue Nov 26, 2013 6:04 am

As anyone who has seen my posts on other threads will know, I'm new to the UP (Plus 2). I got it primarily to print custom ABS cases and other parts for the work I do with large multi-rotor helicopters used to fly videocameras (such as the Cinestar 8).

I was thinking that the cases would be clamshell style cases, with mounting standoffs on the inside base of the case for electronics boards, and then self-tapping screws holding the upper and lower parts of the case together.

I was wondering what the "approved" (as in, used by the gurus on this forum) mounting screws might be? It seems like Type Y Number 4 self-tapping screws, perhaps 1/4" long, would be fine for holding a printed circuit board to the stand-off.

I was curious as to what folks used for holding the two halves of the ABS case together -- in some cases (pun intended) I might need to have a case that was quite deep -- like about 1 1/4" inches -- so I was wondering whether you can even get long Number 4's or whether I need to go to Number 6's.

I'm in the USA as you can infer from the Imperial measurements. The other alternative was to use M2.5 or M3 machine screws to hold the top and bottom half of the case together, but then you have to provide a hex recess for the nut, and a pretty deep recess for the head.

I presumed that there might be a quasi-standard way of doing this for ABS 3D printed cases?
That said, in the world of computers and video there's a saying: "The good thing about standards is that there are so many to choose from." ;)

Andy.
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UpBox and UP Plus 2 : Forensic Software Analyst : Portland, Oregon, USA.

mr6k
Posts: 327
Joined: Tue Feb 14, 2012 11:47 am

Re: Best fasteners for ABS cases?

Post by mr6k » Tue Nov 26, 2013 10:22 am

I have used machine screws and hex nuts on such cases as follows.
Where the hex nut is to be mounted, create a column somewhat wider than the nut, create a hole down the column that equates to the screw O/D. Print the case

Assemble a nut onto a longish screw, heat to around 300c and slowly push the nut down thecolumn to the desired depth.
You should find that some of the melted ABS reforms above the nut anchoring it in place Remove the screw before the ABS totally cools.

Works for me

cheers


Peter

ajohnsonlaird
Posts: 47
Joined: Sat Nov 23, 2013 6:35 am

Re: Best fasteners for ABS cases?

Post by ajohnsonlaird » Tue Nov 26, 2013 11:26 am

mr6k wrote:I have used machine screws and hex nuts on such cases as follows.
Where the hex nut is to be mounted, create a column somewhat wider than the nut, create a hole down the column that equates to the screw O/D. Print the case

Assemble a nut onto a longish screw, heat to around 300c and slowly push the nut down thecolumn to the desired depth.
You should find that some of the melted ABS reforms above the nut anchoring it in place Remove the screw before the ABS totally cools.
That's a great idea, Peter. It's a good way to create a captive nut -- which makes it a nice elegant solution.
Thanks
Andy.
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UpBox and UP Plus 2 : Forensic Software Analyst : Portland, Oregon, USA.

Winstonc
Posts: 17
Joined: Sun Mar 10, 2013 9:02 pm

Re: Best fasteners for ABS cases?

Post by Winstonc » Tue Nov 26, 2013 3:11 pm

I use special brass inserts from McMaster Carr that are designed to be heat set into plastic using a special soldering iron tip also available from them. It works really well.

http://www.mcmaster.com/#brass-inserts/=pjq1k7


David

ajohnsonlaird
Posts: 47
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Re: Best fasteners for ABS cases?

Post by ajohnsonlaird » Wed Nov 27, 2013 6:08 am

Thanks, David.
Nice idea. I'll get some from the candy store (aka McMaster). :)

Andy.
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UpBox and UP Plus 2 : Forensic Software Analyst : Portland, Oregon, USA.

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JuliaDee
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Re: Best fasteners for ABS cases?

Post by JuliaDee » Wed Nov 27, 2013 1:16 pm

I use clamshells with bosses and self-tappers. I make the walls quite thick at 4mm and do a "tongue-and-groove" thing to keep the halves aligned in spite of ABS warpage. Fastenal is a great source for screws and bolts of all types.

http://www.fastenal.com/web/home
Screen shot 2013-11-27 at 8.14.45 AM.png
Screen shot 2013-11-27 at 8.14.45 AM.png (25.96 KiB) Viewed 9797 times

ajohnsonlaird
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Re: Best fasteners for ABS cases?

Post by ajohnsonlaird » Fri Nov 29, 2013 9:58 pm

Thanks Julia.
I sent you a PM regarding your nozzle thermostatic control, btw.

Andy.
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UpBox and UP Plus 2 : Forensic Software Analyst : Portland, Oregon, USA.

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JuliaDee
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Re: Best fasteners for ABS cases?

Post by JuliaDee » Fri Nov 29, 2013 10:22 pm

ajohnsonlaird wrote: I sent you a PM regarding your nozzle thermostatic control, btw.

Andy.
I responded to the email address you provided - did you not receive my reply?

julia

ajohnsonlaird
Posts: 47
Joined: Sat Nov 23, 2013 6:35 am

Re: Best fasteners for ABS cases?

Post by ajohnsonlaird » Sun Dec 01, 2013 6:13 am

That's weird....no. I didn't get your reply. I'm starting to have my doubts about the reliability of Apple mail.
Let me PM you another email address if you don't mind?

Thanks
Andy.
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UpBox and UP Plus 2 : Forensic Software Analyst : Portland, Oregon, USA.

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