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Using Arduino => General Electronics => Topic started by: saildude on Nov 11, 2019, 08:15 pm

Title: Simple Questions About Solder Proto Boards
Post by: saildude on Nov 11, 2019, 08:15 pm
I see the traces can be cut on the Proto Board - but how do I cut a trace?  I tried a bit with a knife and no luck.  Any suggestions?  I have a Dremel tool if that helps.

The holes are through plated so can I stick a wire down from the top and solder the wire from the top?  The board will be mounted where I will not have access to the bottom for final assembly

Thanks Much

https://www.adafruit.com/product/1609 (https://www.adafruit.com/product/1609)
Title: Re: Simple Questions About Solder Proto Boards
Post by: Grumpy_Mike on Nov 11, 2019, 09:14 pm
Quote
I tried a bit with a knife and no luck
You need a scalpel or a Stanly knife. Make two closely spaced parallel cuts on a track and then remove the copper in between the cuts with the blade.

Or you can use the tip of a twist drill turned by hand in the hole. A tool that does the same job, but better because the angle on the tip is more suited for the job, is called a "spot face cutter". spot-face-cutter (https://cpc.farnell.com/unbranded/22-0239g/spot-face-cutter/dp/PC00066)
Title: Re: Simple Questions About Solder Proto Boards
Post by: saildude on Nov 12, 2019, 01:48 am
Thanks - I will give it a try with a Utility Knife / Box Cutter and see what happens
Title: Re: Simple Questions About Solder Proto Boards
Post by: krupski on Nov 12, 2019, 02:25 am
I see the traces can be cut on the Proto Board - but how do I cut a trace?  I tried a bit with a knife and no luck.  Any suggestions?  I have a Dremel tool if that helps.

The holes are through plated so can I stick a wire down from the top and solder the wire from the top?  The board will be mounted where I will not have access to the bottom for final assembly

Thanks Much

https://www.adafruit.com/product/1609 (https://www.adafruit.com/product/1609)
First of all, let me add a plus vote for the Adafruit protoboards. They have gold plated thru-holes with good, thick traces and the holes are large enough to allow several leads at once to be inserted.  As I always say in my reviews of those protoboards, it's obvious that they were designed by someone who USES protoboards and knows what features are important.

Note I am not in any way affiliated with Adafruit... I'm just reporting the facts about them.

Now to your question. When I need to cut a trace between two pads, I use a new single edged razor blade and, with a corner tip of the blade push into the trace and board right where the pad circle transistions into the trace.  Of course you need to do this twice. .. once for each end of the trace to be removed. The copper trace will "bow up" slightly on each side of the cut. Then use the razor blade to get under the trace and "flip it off."  This may take one or two tries.  Then, carefully examine the cut area and remove any remaining microscopic bits of copper left behind.

With the razor blade, either be very careful or else use leather work gloves. If I had a dollar for each cut I've gotten from doing this....

Oh yeah also wear safety glasses. The razor blade metal is very hard and brittle. If a piece snaps off and hits your eye... :smiley-eek-blue:
Title: Re: Simple Questions About Solder Proto Boards
Post by: larryd on Nov 12, 2019, 02:28 am
Use a 45° or 90° 'D' bit with you Dremel.

Center the bit on the hole, advance the bit into the PCB until the trace is severed.

(https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQAiV4B934cn4hKAo6gG7PxhFC14uDzfkr27AUbXRieievSDEhx)






Title: Re: Simple Questions About Solder Proto Boards
Post by: krupski on Nov 12, 2019, 02:49 am
You need a scalpel or a Stanly knife. Make two closely spaced parallel cuts on a track and then remove the copper in between the cuts with the blade.

Or you can use the tip of a twist drill turned by hand in the hole. A tool that does the same job, but better because the angle on the tip is more suited for the job, is called a "spot face cutter". spot-face-cutter (https://cpc.farnell.com/unbranded/22-0239g/spot-face-cutter/dp/PC00066)

If I want to break the connection between, say, pin 1 and pin 3, I use a 3/32 cobalt drill to remove the pad at pin 2 since this is easier than the razor blade method. Also, I spin the drill by hand. It would grab the board and make a 3/32 hole if i used a drill motor.

Note to everyone: The PC board is fiberglass is VERY abrasive. It will eat ordinary high speed steel drills for breakfast.

Even titanium nitride coated drills don't last long.  A cobalt (not to be confused with the BRAND "Kobalt") drill lasts a bit longer, but the best is a solid carbide drill. These cost more, but the fiberglass doesn't dull them.

Carbide drills are very hard and very brittle and there is a 99% chance that you will break one in a hand drill or drill press.

But, for hand held deburring of a hole or cutting a PC board trace, they are ideal.  Don't drop it though... it will shatter like glass.
Title: Re: Simple Questions About Solder Proto Boards
Post by: krupski on Nov 12, 2019, 02:58 am
Use a 45° or 90° 'D' bit with you Dremel.

Center the bit on the hole, advance the bit into the PCB until the trace is severed.

(https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQAiV4B934cn4hKAo6gG7PxhFC14uDzfkr27AUbXRieievSDEhx)







I am afraid of using any kind of drill, reamer or cutter on a trace between two adjacent holes. The start point (center) must be perfectly placed, and cutting even the slightest bit too deep scoops away some of the copper of each pad.

If I use a drill small enough to fit between the pads, then I have to drill almost 3/4 of the way through the board to get the entire trace.  Even then a little "crescent moon" shaped bit of copper remains on each pad, requiring razor blade surgery to remove it.

That's why I use the razor blade for adjacent pad traces.
Title: Re: Simple Questions About Solder Proto Boards
Post by: larryd on Nov 12, 2019, 03:17 am
I center the bit on the hole (use a drill press) then drill out the diameter.
(https://cdn.shoplightspeed.com/shops/613820/files/5230934/foredom-electric-ho540-foredom-drill-press-dp-30-f.jpg)


A burr in the Dremel works well on traces between holes.
(https://home.janaszek.org/uploads/62699-1.jpeg)

(https://nathandumont.com/files/images/stripboard_cut_tracks.preview.jpg)

Also Google:

spot face cutter stripboard





Title: Re: Simple Questions About Solder Proto Boards
Post by: Grumpy_Mike on Nov 12, 2019, 09:27 am
This is an example made with a scalpel of how you can cut tracks between holes.
(https://forum.arduino.cc/index.php?action=dlattach;topic=645859.0;attach=332565)

This is an example of cutting along the length of a track so you can use surface mount components with 0.05" pitch.
(https://forum.arduino.cc/index.php?action=dlattach;topic=645859.0;attach=332569)
Title: Re: Simple Questions About Solder Proto Boards
Post by: krupski on Nov 13, 2019, 12:20 pm
This is an example of cutting along the length of a track so you can use surface mount components with 0.05" pitch.
(https://forum.arduino.cc/index.php?action=dlattach;topic=645859.0;attach=332569)
That is an awesomely clever idea. I just added it to the ferrite core memory in my head (they didn't have solid state memory way back when I was born).   :D
Title: Re: Simple Questions About Solder Proto Boards
Post by: saildude on Nov 13, 2019, 07:26 pm
Thanks all - I need all five pads so the drill a pad out for my application would not work.

I did try the Utility Knife method by making a few cuts between pads - that seems to have broken the trace without needing to scrape traces off - checked with a meter - so will probably use the utility knife but use a straight edge for more control
Title: Re: Simple Questions About Solder Proto Boards
Post by: Grumpy_Mike on Nov 14, 2019, 06:12 am
Quote
that seems to have broken the trace without needing to scrape traces off
Yes it will cut the track, but if you think about it this will leave a raised length of copper that might make contact again if it is pushed down. I would double check by going over the cut with my finger nail, smoothing it down. Then check with the meter again.
Title: Re: Simple Questions About Solder Proto Boards
Post by: saildude on Nov 14, 2019, 08:37 am
I would double check by going over the cut with my finger nail, smoothing it down. Then check with the meter again.
I can do that, was thinking of also making a small scraper I could drag in the removal area

thanks again
Title: Re: Simple Questions About Solder Proto Boards
Post by: DrAzzy on Nov 14, 2019, 08:50 am
I use larger hunks of protoboard so that I don't have to cut any traces >.>

Cutting traces always sucks, and when you're trying to do it on decent protoboard - double-sided, thick traces, etc, it's particularly difficult. I avoid doing it on protoboard entirely, and only do it when I'm modifying existing PCBs for some reason.

Oh, gee, guess what, I happen to sell just such protoboards, originally made out of frustration with available options. (https://www.tindie.com/products/drazzy/2-x-4-prototypingproject-boards/)

Title: Re: Simple Questions About Solder Proto Boards
Post by: larryd on Nov 14, 2019, 05:06 pm
You can do stuff like this:

Edit
Try a small drop of 'Super Glue' on motherboard and small smear of 'Super Glue Accelerator' on the bottom of the cutout pad.

See post #43.
 https://forum.arduino.cc/index.php?topic=445951.msg3091556#msg3091556      (https://forum.arduino.cc/index.php?topic=445951.msg3091556#msg3091556)

(https://i2.wp.com/www.pbase.com/daverichards/image/136603886/original.jpg)

(https://forum.arduino.cc/index.php?action=dlattach;topic=346333.0;attach=137269)



Title: Re: Simple Questions About Solder Proto Boards
Post by: saildude on Nov 14, 2019, 07:20 pm
@larryd - Thanks

Wow & very interesting - good job

And I do have a Whitney Punch from a previous life
Title: Re: Simple Questions About Solder Proto Boards
Post by: larryd on Nov 14, 2019, 08:44 pm
Try a small drop of 'Super Glue' on the motherboard and a small smear of 'Super Glue Accelerator' on the bottom of the cutout pad.



Title: Re: Simple Questions About Solder Proto Boards
Post by: krupski on Nov 15, 2019, 06:27 am
See post #43.
 https://forum.arduino.cc/index.php?topic=445951.msg3091556#msg3091556      (https://forum.arduino.cc/index.php?topic=445951.msg3091556#msg3091556)

(https://i2.wp.com/www.pbase.com/daverichards/image/136603886/original.jpg)
Now that's what's called "surface mount technology"!
Title: Re: Simple Questions About Solder Proto Boards
Post by: larryd on Nov 15, 2019, 11:10 pm
Another method for point to point wiring.

See posts #692-695

https://forum.arduino.cc/index.php?topic=445951.msg4373170#msg4373170 (https://forum.arduino.cc/index.php?topic=445951.msg4373170#msg4373170)

(https://forum.arduino.cc/index.php?action=dlattach;topic=445951.0;attach=333253)