PCB drilling own pth

Thread Starter

VancityTechie

Joined Jan 5, 2021
2
Hey,

I have a circuit made that has pads on the top and bottom of a PCB at the same spots however they are not connected through the circuit with via or pth. What can I do to connect the pads though the circuit? I was thinking of drilling small hole and solder through?
 

andrewmm

Joined Feb 25, 2011
1,757
Good luck driling,
our ready to bin the board ?

PCb's are very abrasive, you need a real high speed drill,
Its also very hard unless you have the board and the drill locked into a press, to keep them central on the pad.
and if the speed is not high enough or the pressure wrong the pad will come off.

Yes drilling through can and is done, but its not without risk.

As for once you have drilled,
as @ronsimpson says,
the solder wont flow through on its own,
You can get solder pins , but most people just cut the end of a through hole resistor and stick that through the hole.
 

sagor

Joined Mar 10, 2019
479
Depends on how you make the board. If using a milling (CNC) machine (isolation routing), best to drill the holes before machining the pattern. That way, you don't twist out the pads when drilling. Only then you machine or etch your board. This requires some precision in spotting the drill holes of course, as with a CNC machine.
A wire through the hole will work as a VIA ok.
 

jpanhalt

Joined Jan 18, 2008
11,088
Good luck driling,
our ready to bin the board ?
I think you over emphasize the difficulty. I routinely drill the few homemade boards I make nowadays and add wires to connect the sides. I use 24 AWG tinned, bare wire, which is about 0.020" in diameter. Drills are carbide and most are surplus that have been resharpened.

1609870122398.png

For ordinary TH components and pinheaders, I use a #66 drill (0.033" dia.). For my knitting, I use a #72 (0.025") or #75(0.021") drill. The #75 holds the wire snugly while soldering. The # 72 is a little looser. If you simply squeeze one end a little, it won't fall out while soldering.

I use an ordinary bench/floor drill press, not a precision desktop one, and don't turn the speed up way high. Of course, the speed is higher than you would use for a 0.25" drill. A small prick with a center helps the drill center. PCB's are not clamped to the drill press so they self-center just a little. A higher drill speed negates that advantage/need.

The only drill bits I have broken are the #66, as I get in a hurry and a little careless on occasion. I have more than a 1000 that I got at a very reasonable price years ago (resharpened surplus from a PCB house). The problem with breaking a drill is not the cost. It is the difficulty of removing the little stub that often remains in the PCB. You cannot just drill over it.
 

dl324

Joined Mar 30, 2015
13,145
I've never had problems with pads twisting off when drilling homemade boards after etching; they have a hole in the center. I use the pad openings as a guide for the bit. I use carbide bits in a Dremel-like tool (12000 RPM) in a holder.
clipimage.jpg
It has more play than I'd prefer, but I keep bit travel to a few tenths of an inch or less.
 

MrChips

Joined Oct 2, 2009
24,240
I have drilled many PCBs manually in my lifetime. You cannot use a handheld tool such as a Dremel rotary tool.
You have to use a high speed drill press and carbide bits. You must have zero lateral movement otherwise you will break the bit. Ask me how I know. I use a Unimat machine lathe in drill press mode and at highest speed the pulley setup will allow.

1609873306732.png

As for PCB layout, make sure that you can access the pad on the upper layer component side. You cannot use standard through hole IC DIP sockets. Avoid running traces underneath a DIP IC because you cannot see if you have made a proper solder connection to the IC pin.

You should have no problems with usual through hole resistors and capacitors. I save the excess resistor legs to be used as vias or jumpers (that's the pack-rat in me).
 

ericgibbs

Joined Jan 29, 2010
13,686
hi VT,
If its just a one off PCB that needs drilling, a budget option is this mini hand drill.
Use a 1mm Dia drill if the pads are big enough.

For some drilling I use a miniature 9Vdc hand drill, just take it steady and hold firmly
Place the PCB on a flat piece of wood while drilling and secure with masking tape,

E
 

dl324

Joined Mar 30, 2015
13,145
If you have adequate technique and hand-eye coordination, you can drill with a hand held Dremel tool. @cmartinez posted a video of himself doing it. Don't say can't to the man who's doing it...

My setup has more lateral movement than I'd like, but I've never broken a bit drilling. That usually happens when I bang the tip on something or lay one down and put something on it. I use something around 0.029" for the regular holes.
 

Thread Starter

VancityTechie

Joined Jan 5, 2021
2
Thanks for all the help!

Sorry I forget to mention this is a flexible board of only 0.2mm thick it is easy to go through but putting wire through is a little difficult I want to keep the pads flat. Any suggestions?
 
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