Drilling out a hole?

[AKBessy]

I have a question about soldering -- or avoiding the soldering iron as much as possible.

After removing an item from a board, is drilling out a hole an acceptable method of "cleaning out" a hole? I ask because my husband has these german-made (Kemmer Prazision) drill bits that are for printed circuit boards. The ones he has are really tiny in diameter, .018, and sharp as a son of gun. He was fooling around with one when he first got them by putting one on his fingernail and twirling -- it was going through the fingernail with no pressure and no effort!

I tried this method with the MSI board that I have been working on and I was comfortable with this, but not sure if it is not acceptable because of contaminates from the old solder maybe?

Here's a picture of the cool drill bits and a link to Kemmer's website. I am sure they cost an arm and a leg - I have no idea where my husband got his from and he can't remember either (obviously didn't pay for them ha).


Kemmer Praezision

[kc8adu]

Re: Drilling out a hole?

very risky.
not recommended.
rip out the thruhole and junk the board.

[Topcat]

Re: Drilling out a hole?

definitely don't do it. Search in the FAQ and how-to's, there's a lot of info on exactly why not. Too many have destroyed their boards doing it. Hit up a local dentist and sweet talk them into selling you one of their stainless picks.

[AKBessy]

Re: Drilling out a hole?

Thanks for the input - good advice to know! :-)

[starfury1]

Re: Drilling out a hole?

There is a thread on the FAQ's that covers using the pick method here.

You might have already read it...
(thanks willawake, its a biggie others have added to it too. Thks)

you have been given very good advice by TC KC8

The reason why its not recommended to drill out is that the pcb is made up of layers of tracks and insulation like having a multi story sandwich.

The Via or plate through hole goes vertically from the top to the bottom
Some of the tracks in the middle will be connected to (cylinder of metal)
plate through hole.

So if you drill it out there is a chance you will cut away part or all of the cylinder.
This of course will leave tracks in the middle open circuit.

So thats the risk you take doing it that way


As to solder..well there always going to be a little bit left...less thought the better

The important thing is to have flux and solder at the same time when resoldering Cap leads

Yeah also to much heat applied to a pcb is not a good thing either....as it can damaged the pcb.....
(sounds like you are trying to avoid this issue)

So yeah it comes down to practice...which is why it recommended that you get some junkie pcb's to practice on.
(something I should do more of)

By "drilling" I suspect you mean you are doing it by hand with the drill bit ?

[AKBessy]

Re: Drilling out a hole?

Thanks for the reply starfury. Ya, these bits are so small and sooo sharp - no additional pressure would be needed other than by a very light hand. However, I got to thinking about the dangers of damaging the sidewalls of the hole as you mention and little bits of solder falling into places unbeknownst to me and possibly shorting something else out.

I will read some more about this in the forum boards when I get a chance.

[starfury1]

Re: Drilling out a hole?

No worries, figured thats probably what you were doing...they do look like nice drill bits...

and yeah I should have mentioned that re rouge solder bits floating around

With any solder work you should check the PCB throughly with a good mag glass or loupe...looking for slithers shorts or small balls...it happens

Having said that there are those out there that do drill

I personally think the other method is safer, if you can tech yourself how to do it
or a proper De- soldring rig is the go
they are not cheap for a quality unit thought.....I have an El-cheapo


Also when de-soldering just add a smidgen of solder to the tip of you iron to help heat transfer

have a browser through the faq's

Cheers AK

happy to help

[tazwegion]

Re: Drilling out a hole?

I have a question about soldering -- or avoiding the soldering iron as much as possible.

After removing an item from a board, is drilling out a hole an acceptable method of "cleaning out" a hole?

I use a superfine jewelers' screwdriver (standard tip) and whilst supporting the board on thick cardboard (yeah a pizza box will do) apply slight pressure to the top of the screwdriver while rotating it's shaft, I guess in a way it's sort of manually drilling out the old solder

Hopefully when I finished paying off my new soldering station, it should be even easier to remove excess solder with better tools

[AKBessy]

Re: Drilling out a hole?

Talk about practicing soldering: I went to a local computer repair/sales shop to yak with them about FETs. We got to talking about soldering and they told me to go over to their junk pile and take all I wanted to practice soldering on ;-). They figure it was cheaper for me to take it and have to deal with disposing of it. So, I grabbed some boards with different things on them, so I am ready to set out and see what my capabilities and limits are. Wahoo! LOL

[archae86]

Re: Drilling out a hole?

as to where such bits come from:

Folks who fabricate PCBs use such bits by the jillion (did you ever wonder how all those holes come to be in the boards?). They discard them at a wear point which still leaves them able to drill for lesser uses. Plenty of surplus places will sell them to you in large lots for practically nothing.

Even the new ones are surprisingly cheap if you don't mind buying 50 at a time.

BUTTTTT... They are hard and brittle (need to be hard to last long enough to be useful in their original application), and thus very unforgiving of chuck wobble and such. If you use one be sure you won't get hurt if it shatters.

Brave men don't wear eye protection. Smart men keep their eyesight.

[AKBessy]

Re: Drilling out a hole?

"BUTTTTT... They are hard and brittle (need to be hard to last long enough to be useful in their original application), and thus very unforgiving of chuck wobble and such."

Absolutely tried and true! Hehe. If one is dropped from a height, it easily breaks also! They don't like to be wobbled and used at an angle.

As for the safety glasses - I am wearing them even in my avatar ;-).

[tazwegion]

Re: Drilling out a hole?

As for the safety glasses - I am wearing them even in my avatar ;-).

And to think, I thought they were just a fashion accessory LMAO


BTW plenty of spare components on those trashed motherboards, awesome!

[kc8adu]

Re: Drilling out a hole?

i know a machine shop owner who would likely shoot anyone who he caught drilling on boards.an idiot "tech" did that to a one of a kind unobtainium board in a machine.
he made quite a mess of it.
he got fired and when i got it running again the owners wallet was a lot lighter

[AKBessy]

Re: Drilling out a hole?

Well, I have crossed the line and will not put a drill -- even a very tiny, tiny drill on a hole again ;-). I can't get my board to go - doesn't help that I am still having a hard time understanding my numbers. But, this has been wonderful practice - so all is not lost!

[999999999]

Re: Drilling out a hole?

I have done it fine, though I don't prefer nor like to, you just have to be aware of what you're doing.

The bit has to be small enough with a little margin for being a little off-center in the hole, but at least as large as the component lead. This means it's not always possible unless you have larger holes or a very good selection of bit sizes and know the component lead size (which you might).

There can't be a solder bump that puts it off-center. You don't want to break the bit and get a piece of tiny metal lodged anywhere you cant get it out. It also throws tiny pieces of solder out which is a pain to get off anything.

The easy answer is find a better way like a solder sucker, but yes it is possible in an emergency if you are careful.

[Harvey]

Re: Drilling out a hole?

I've found that on the occasions that you just can't get the hole clean, heating the back of the hole while gently pushing the capacitor lead in can often do the trick. In fact in the last board I recapped I fitted most of the capacitors that way - cut the leads of the new caps down to about 10mm and 'wobble' them in the same way as you wobble them out.

It takes a bit of practice and you need to be careful about the irons temperature - and of course you then need to apply a bit more heat and fresh solder after the cap is flat to the board - but it works.