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isochronic
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Joined: 21/01/2012
Location: Australia
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Posted: 02:11pm 03 Dec 2016

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The barrel sockets used for power connectors need three
small slots cut on pcbs. Is there a good way of cutting them ?
(Apart from manufacturer milling, that is). I can cut them with
a Dremel clone by hand but am fairly lousy at it

Grogster

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Joined: 31/12/2012
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Posted: 10:28am 04 Dec 2016

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Slotted holes are very difficult to do at home. I used to just make sure the pad was big enough to be able to drill a big hole in the pad, that was large enough to allow the tab from the DC socket to pass through it, then just fill it up with lots of solder. Seems crazy, but it does work, and saves you having to try to cut slots at home.

Smoke makes things work. When the smoke gets out, it stops!

bigmik

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Posted: 03:09pm 04 Dec 2016

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Hi Chronic,

Yes what Grogs said.... but you might be able to reduce the hole dia by crushing the blades on the socket with pliers so they are wider but skinnier... if that makes sense.

Kind Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

isochronic
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Posted: 05:42pm 05 Dec 2016

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Thanks - useful stuff. The manufacturers that cut the slots
tend to charge too much, ok for a prototype maybe but not for a batch

(ed) Excellent !! Combining both ideas ..
The tabs on the connector are 0.1" eg 2.54 mm..so if I
"wrapotate" them around into a circumference they should fit a 1 mm hole..
Nice. Edited by chronic 2016-12-07

isochronic
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Posted: 03:08am 06 Dec 2016

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!@#$% the tabs are brittle and tend to break up
before bending much.

bigmik

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Posted: 10:07am 06 Dec 2016

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AHHHHH,

Sorry, probably not the best idea then..

Maybe then as Grogs said drill a bigger hole but depending on the size of your pads you might drill them away..

You `could' try drilling multiple holes close together then punching a small flat blade screwdriver through them and finishing up with a scalpel.. But a lot of work..

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

Bryan1

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Posted: 09:43pm 07 Dec 2016

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Just drill two holes where the diameter equals the slot width then get a small tapered round file to file the inner section and job done.

Cheers Bryan

isochronic
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Posted: 11:00pm 07 Dec 2016

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The preferred slot width is ca 0.5 mm .. I have searched a bit,
apparently jewelers' suppliers have "piercing saws" which are designed
to use a small starting hole, maybe they are the go, sounds expensive though.
The reason I ask is, I have tried two pcb houses.
> Osh Park mill and plate the slots automatically at 1mm as standard but they charge a lot,
> Pcbway are good for routine pcbs but the budget price and fast production preclude the slots I guess, I haven't tried ordering any slot milling as yet though.

There is a lot of mechanical stress on the connectors so a good fit to the pcb
is probably required for strength (at a guess ?).

Edited by chronic 2016-12-09

isochronic
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Posted: 01:47am 19 Dec 2016

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Success !

I was advised the saws tend to break easily.
So, as suggested, I tried a very small milling burr cutter...0.8 mm...first attempts lousy but now much better.. dumbo operator (me) assumed collet was centering it well, not exactly reality ! Much cheaper than I thought.

isochronic
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Posted: 02:22am 01 Jan 2017

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As it turns out, for my last pcbs, PCBway cut and plated the slots anyway ..nice..and a lot neater than my messy attempts.

bigmik

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Posted: 05:13pm 01 Jan 2017

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Hi Chronic,

I didn't think of it at the time but my Mup 3 also has mounting slots for the mini USB connector.. I have had 2 batches made, 1 from PCBway and 1 from Shenzhen2U and both made the boards with plated slots without question.

Kind Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

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