pcb drilling

[disabled_shredder]

Best  I've found is take an auto punch and push but don't actuate or you rip it apart and drill from the copper side I use acitone to get the black off first it makes it easier to go over w steel wool after to freshen up the copper to get a good bond w solder. And a #60 bit is absolutely perfect for all holes not to big or small and if you use 24g wire you don't have to change bits.

[PRR]

Drill RPM should increase as bit size decreases.

If a 1 inch (25mm) bit should turn 500-1000RPM, then a 1mm bit should turn 10,000RPM-25,000RPM.

You can't get close to 25,000RPM with a hand-drill. 1,000 RPM is fast. Going faster means the drill shakes like a maniac, bit snaps.

If RPM is low, cutting is slow. Prolonged friction hardens or burns the work and dulls the bit. You get frustrated. You press harder. Bit snaps.

Go ahead and try. I've done some 1/16th inch (1.6mm) holes with hand-drill in PCB stuff. I've also broke a lot of 1/16" bits.

As said, Dremel (even the lowest-power semi-toy model).

Or the stronger toy-car motors, if you can mount a bit well-centered.

[deadastronaut]

i use a minicraft...and no press., i bought mine for £10.00 ebay...

http://www.rapidonline.com/tools-equipment/minicraft-mb150-hobby-drill-30619/


cheap as chips brand new too..
http://www.electronelec.co.uk/acatalog/MINICRAFT_MB150_DRILL.html


great little cheap drills..

[GGBB]

Looks like a #70 bit will work for most components from what I've read.

#70 has worked for me for everything except power diodes (1N4001, 1N5817, etc.) and off board wires.  For those things I use a #65, and I also have a #60 in case something big comes along which it hasn't yet (but I have plans to use molex connectors in a project).  However, #70 is also a fairly close fit, so for things like box caps, ICs and sockets, you have to be fairly accurate with centering the drill or else these types of components won't fit properly because the holes aren't spaced and lined up properly and don't have enough give.  If you want a little fudge room, go with a #68 or just use a #65 for everything.

Drill from the copper side. If the etched center of the pad is properly sized, it acts as a centerpunch dent(?) and will center the drillbit in the center of the pad as you drill. Light touch holding the pcb as you lower the drillbit, the pcb will shift to center the bit and then apply hand pressure to the pcb so it doesn't move, drill through. Might be a bit of fiber at the exit hole but no worries, wet sand it away, iaslo wet sand the etch resist off when the time comes. (And don't forget eye protection and dust mask.)

I'll second all of that (although the mask isn't necessary with a regular drill press as the slower speed doesn't kick up any dust).  But a word of caution about the light touch.  With carbide bits being as sharp and brittle as they are (especially with a #70) this is a delicate matter because the bit will grab quite quickly (especially with a Dremel) and twist/pull the board and the bit will SNAP - happened to me once with a #65 exactly because I had too light of a touch.  So be VERY careful with that.

[peterg]

All good advice. Thanks everyone. I picked up a handful of micro drill bits - the ones with the plastic ring. (3 for $1 at Active Surplus for those in the Toronto area). I got slightly larger sizes to match the holes in perf board. I'll work on using smaller bits once I get some practice.

[CodeMonk]

I use A #65 for almost everything.
For pots and switches a little bigger.

I also set my drill press at slow speed otherwise the bits wobble to much.
I guess that's what I get for using a $50 drill press.

[nosamiam]

This question comes up from time to time and I have found a just about perfect solution. My secret weapon is a Dremel engraving bit. It works amazingly well, is inexpensive, readily available and durable. It looks like this (the one on the bottom):



I've done about 20-25 boards, several of them as big as 5"x6" and I've NEVER broken a bit! The shaft of the bit is really thick compared to the shaft of the standard bits everyone's using. I'm on my second bit but only because my first one somehow got wet and the little ball on the end rusted and disintegrated. The ONLY two things I don't like about it are 1) that the size I have is pretty small and I have to ream out the holes with an X-acto knife. I haven't shopped around for a slightly larger size, but there probably is one that is just right. And 2) the copper pads have a little pucker up slightly like little volcanos from the taper of the shaft. It doesn't cause any problems with soldering at all and once the board is populated, you can't see the volcanos. It just looks funny right after drilling. I use it with a regular variable-speed hand-drill. I haven't tried it with my Dremel, but I imagine it would work just fine. I feel like I'm more in control if I go with low speed.

As far as technique, I use sort of an "arm-wrestler's grip." I put my elbows on the table/desk. I hold the grip of the drill in my right hand with the bit pointing straight downward (of course) and the body of the drill away from me. My thumb is on the trigger controlling speed and I only use my left hand to steady the drill. Then I just go to work. I clamp the PCB to a piece of wood. It's basically like a human drill press. Doesn't cost anything but the price of the drill which you probably already have.

I can take a pic of my human drill press if the description is confusing.

[peterg]

Thanks nosamiam. Someone else mentioned the engraver tool. I'll give it a try.

[R.G.]

This is what you want:
http://www.micromark.com/microlux-3-speed-mini-drill-press,7797.html
Unfortunately, it's $200 now. I bought one back when they were $100 - or when those dollars were worth $2 in today's dollars, depending on how you look at it.

It's an incredibly precise, smooth tool. I could actually dull carbide bits before I broke them, which is the reverse of what I'd do with a Dremel. Not all Dremel press attachments are equally precise.

Any side to side movement or wobble in the press movement breaks carbide bits.

High speed steel (HSS) drill bits will bend more, but they dull to useless in about 100 holes in glass-epoxy circuit board stock.

[woody alien]

+1 for Dremel and the stand, that was mentioned in the reply #1. That Dremel stand isn't actually 'precise', when you get it out of the box. Luckily it has some brass set-screws,
to sneeze out the excess lag. Takes some adjusting, but it is the only way to get the best out of it.  

So, after I got mine adjusted, there wasn't too much lag anymore, which reduced the wandering drill -phenomena a lot.
Only after that, I got the courage to swap the fast'n'dull 1mm(0.039") HSS bit to a carbide one. Since then, it has worked like a charm.

The drill speed, that I use, is 5000 rpm, being the lowest one, that my Dremel provides. At first, I used something like 20-30k rpm, but the noise was horrible.
It got me thinking: "what am I producing ? is it noise, or holes ?".

To prevent snapping the carbide bit, it helps to use the depth stop or -limiter, so the drill bit goes down only enough, to get through the pcb.

[Gurner]

For anyone in the UK, here's a nice compact pcb drilling solution...

http://www.ebay.co.uk/itm/Circuitape-Printed-Circuit-Optical-Drilling-Machine-/181254560873?clk_rvr_id=542223161067&afsrc=1

(the drill comes up from below)

[stallik]

Compact?

[KazooMan]

I have a good quality floor standing drill press and I have drilled many boards with it.  It works OK, but it can be a bit unforgiving if you hold the board down really tightly and the tip of the bit tries to wander into the little detent in the copper left after etching.  Time to put a new bit in the chuck.

I finally discovered that I had much better luck with a hand-held Dremel tool.  The one I have is very compact and lightweight (a pistol grip style with rechargable battery that I don't think they make any more).  I really like the 3/32" shank drill bits from Smallbear.  I use a #67 for most work.  It is the exact size for the pins on sockets and such.  I occasionally use a #57 for parts with thicker leads.

http://www.smallbearelec.com/servlet/Detail?no=592

They fit the Dremel perfectly.  I hold the drill like a big pencil and actually let it find the center detent of the hole by itself and then push down to complete the hole.  MUCH faster than trying to line up the drill press and I break fewer bits.  I can actually use a bit until it gets so dull I decide to change it out.

My Dremel tool is getting on in years and I looked for a replacement, but they don't seem to be available any more.  So, I purhased one of the current corded models and got the handpiece with the flexible shaft to go with it.  The drill motor hangs from a hook above the bench taking all of the weight off the setup.  The handpiece is a very comfortable size to hold and work with.


Smallbear also sells these bits. They are resharpened bits from industrial use.  I haven't tried them yet, although I did try some lust like them from another vendor a while ago.  The ones I tried broke very easily.  I will give the Smallbear bits a second chance.  I broke the other ones using my drill press.

http://www.smallbearelec.com/servlet/Detail?no=1442

[davent]

Put this up in a parrallel thread- working with ideas presented by R.G. Keen over the years. Haven't given it a run through yet but no reason it shouldn't work.







Flipped the Dremel carriage, Dremel stand screwed to worktop. Drillpress table swung out over the Dremel stand so now have a table. Cheap USB Endoscope held in a Magnetic Base Flashlight holder from LeeValley.

Downloaded free Web camera software from Oasis Scientific as the supplied software wasn't doing it. Found another free utility that by Hotkey turns the cursor to fullscreen crosshairs. Attach a scrap piece of PCB to the drillpress table, drill a test hole, line up the crosshairs with the test hole, hit another hotkey the crosshairs freeze in place returning the cursor to normal. you now just line up your pads with the crosshair and drill away.

As far as the carriage swing of the Dremel, on the old one a have there's a yoke that travels up and down the depth gauge and it's this yoke that limits the swing of the carriage but it's not tight to the depth marker. I heatshrinked each arm of the yoke and that totally eliminated any play that was there before when advancing the drill carriage. You can see th heatshrinked yoke in the first photo.

dave

[Govmnt_Lacky]

Dremel and a #65 bit........

FREE HAND baby!!! 

Broken 3 bits in 4 years 

[R.G.]

Dremel and a #65 bit........

FREE HAND baby!!! 

Broken 3 bits in 4 years 

Good hands. I've broken as many as three in an hour.

[davent]

Dremel and a #65 bit........

FREE HAND baby!!! 

Broken 3 bits in 4 years 

Carbide?

[disabled_shredder]

FYI I had a bit "accident" while moving and broke my 25$ carbide bit in futility trying not to waste it I tried using it broken. Holy sh@t it drilled like a charm. So guys when the bit goes dull just take some pliers and snap off past where the bit used to stop bc we all know there's plenty of bit and give it a try on a test board. It's a great money saver without sacrificing quality. I expect scepticism but try it If it worked for me I'm sure it will work for you! Pls post any findings pos or neg to my theory. I want to see if its a fluke or not. Thanks.

[davent]

I use the busted bits as well they just don't enter as cleanly for me. Anybody ever found a source for short shafted carbide bits as what i see offered are unnessarily long for how we use them?

dave

[disabled_shredder]

Davent I just use the dremel quick lock cutoff wheel (not the one w the screw those are Terrible) and cut the base down some to make them shorter otherwise they wobble like crazy in the dremel and the broke bits went perfectly into the pcb without any "drifting"!