PCB drill press idea's - revisited

[Blueteeth]

Hey there,

About... two years ago I started a thread about what people use for drilling PCB's, and got responses ranging from 'holding a hand drill above it' to expensive presses and DIY CNC machines.

I am still using my PZ541 stand with a dremel 300, both are less than ideal, the runout, and play snap carbide bits maybe every 50 holes (yeah.. expensive). Despite using mostly surface mount, drilling is a necessary evil of PCB's, be they for TH components or via's. I will of course attempt to modify/sort out the stand, and look for hobby drills on ebay (minicraft, proxxon, maxicraft etc..) because the Dremel 300 is loud, hot, heavy, and somewhat sloppy for PCB work.

So as a new project, research, something to do, I've been researching on the best available drills/stands, as well as building my own - from scratch, using a brushless motor (for reduced noise, higher speed) and precision guides rather than a rack and pinion job. I'm not a mechanical engineer, but the web is full of awesome DIY CNC builds, and even though at the moment I'm just after a drill press - the Z-axis mounting idea's are great.

I'd like to just ping others for idea's, again, what people use for drilling (stands, presses, drills, bits, rpm etc..) as well as idea's for designing/building my own.

Currently taking apart old printers for bearings, runners, and fixings to make my life slightly easier. In the mean time, bidding on minicraft drills (MB150, proxxon micromot 50/E...) and would like reviews of these, as many on the web are for wood work - not high RPM PCB drilling.

I realize there are many many threads about this, but there are also so many options, brands, and cost range, so it would be nice for others to show off their gear, as well as help out anyone following the thread who dreads drilling their DIY PCB's as much as I do.

Cheers,

Blueteeth

 

[misterT]

I do not understand the problem. Sounds like you are obsessed to find the perfect drill.. I've never had problems drilling holes to PCB. I have used cheap hand-held drills etc.

But, to answer your question.. one of the best hobby tools I've used are Proxxon tools. Way better quality than Dremel. Dremel is well marketed product, but the quality is cheap compared to Proxxon. And the line of products is very impressive.

https://www.proxxon.com/eng/

 

[Blueteeth]

Hi there, yeah it wasn't a simple question, sorry :/ was more just trying to get folks to list their experiences with various drills, methods, brands and tools. I'll admit I do seem to get a bit obsessed with perfectionism, to the point of diminishing returns. I realize that without spending lots of money one can't get a 'perfect' PCB drilling system, but wanted to get idea's before I started buying up drills, or mechanical hardware for my own. The proxxon series caught my eye shortly after I got my dremel (I regretted getting it..) and I'm thinking the 12V micromot series would be more than adequate for PCB drilling.

As for the 'true DIY' approach - I noticed many high quality brushless motors, powerful ones, are available for hobby RC models, helicopters mainly, that go quite cheaply. So if they are significantly quieter, and high enough speed, I could attempt to permanently fix such a motor to a press, along with a sprindle and bearing for accuracy. Not only is this lighter, and quieter, but also smaller - and I haven't seen much info on the use of such motors for drilling.

 

[misterT]

I have to add that once I wisited The Finnish School of Watchmaking and they used finger drills for the extremely precise and quality work that is required. The smaller the hole, the slower they drill.. opposite what metal workers usually do. The work they did was really, relly impressive. Actually that helped me when I had to drill PCB with a very poor (shaky) hand-drill. I set the drill as slow as possible and got the job done perfectly.. took some time, but anyway.. Experience and skill are as important as the tool.

 

[misterT]

As for the 'true DIY' approach - I noticed many high quality brushless motors, powerful ones, are available for hobby RC models, helicopters mainly, that go quite cheaply. So if they are significantly quieter, and high enough speed, I could attempt to permanently fix such a motor to a press, along with a sprindle and bearing for accuracy. Not only is this lighter, and quieter, but also smaller - and I haven't seen much info on the use of such motors for drilling.

That is a difficult question for a hobby project. How much is your budget? I think good RC motors are very well branded and because of that they are over priced. You should at least compare prices to some good quality industrial motors like Maxon (Sorry, this is the second time today I advertise Maxon, but they are the industry leader). Buy a good quality industrial motor and you do not have to pay extra for (precision) bearings.

EDIT: I'm searching maxon products.. if I find a potentially good one, I'll edit this post for the info.
EDIT: Well.. the prices are quite high (~200 USD) and it is very difficult to compare top-of-the-line motors to hobby RC motors. I would say that 50W RC motor delivers the same power than 35W quality industrial motor. The efficiency is so much better. And the industrial motor will have extremely good ball bearings. https://www.maxonmotor.com/maxon/view/catalog/

 

[Mr RB]

I use a $20 all-metal drill press stand from the hardware store, but instead of inserting a cordless handdrill I glued in a tiny $15 DC "supatool" that has a tiny drill collet.

Being DC I run it from a variable DC power supply, and turn the volts down so it is not screaming and vibrating badly (the main thing that breaks drill bits!). The variable voltage lets me tune a slower speed where there is no resonance so it is nice and quiet.

The overall effect of a metal drill press with no slop, and nice speed controlled micro drill is that there's no need to go any better, so I question the idea of getting specialty hardware or specialty motors/spindles.

The other trick is to break and sharpen your drill bits to make them shorter (or buy shorter bits). There is no need for delicate and weak 15mm flute length when you are drilling 1.6mm thick PCB!

 

[atferrari]

The other trick is to break and sharpen your drill bits to make them shorter (or buy shorter bits). There is no need for delicate and weak 15mm flute length when you are drilling 1.6mm thick PCB!

I always wondered why they are made so long!

You are right, they could last logner, that is, breaking not so often, if they were shorter.

 

[Blueteeth]

..The overall effect of a metal drill press with no slop, and nice speed controlled micro drill is that there's no need to go any better, so I question the idea of getting specialty hardware or specialty motors/spindles.

Good point, however, as I'm having trouble finding a 'metal drill press with no slop', I thought about creating my own One that I can guarantee has no slop (being adjustable) and can have fittings made specifically for different tools - as well as extras like lighting, and a acrylic overlay with reticle for 'aiming'. Sounds ambitioius, and perhaps over kill, but all the above is usually on commercial PCB drill systems design to be used manually. Its just as much a hobby project as a 'useful bit of kit'. In the meantime I will still search for the best presses, currently looking for the old minicraft model.

The other trick is to break and sharpen your drill bits to make them shorter (or buy shorter bits). There is no need for delicate and weak 15mm flute length when you are drilling 1.6mm thick PCB!

Awesome idea! I'm unsure how to ground and resharpen 0.4-0.8mm carbide bits... although I have plenty of broken ones snapped half way down to practice on - in fact I'm glad I kept them now, at one point I was going to try and grind them down for a cheapy CNC bit.

 

[crosslakeguy]

I would not say I dread drilling holes..... hand drilling is time consuming, but not problematic for me. I use a super high speed press 3-5,000 rpm. I dont even use the mechanism to drill....... the etched center of the pcb pin acts as a center for the drill to follow....... and raise the pcb up onto the drill by hand .....being able to see is the key to drilling any board by hand....

 

[MrAl]

Hi,

Yes drilling a PCB is quite different than drilling other stuff. Often a carbide drill is used, and that breaks too easy. The drill press might break it just because the drill bit comes out the other side and the force moves from the tip of the bit to the side of the bit, which of course breaks it. That happens when the drill press movement is too sloppy, as the bit tip touches the work piece and some pressure is applied that causes the drill press to 'unfold' slightly when there is too much slop, and once the bit gets through the work piece the drill press tries to 'fold' back to the same shape (viewed from the side) and that's when the bit breaks. This also happens with hand drilling because once the bit goes through if the angle isnt prefect there is too much force on the side of the bit coming from the side of the hole of the newly drilled hole.

What helps is to drill into the PCB with the carbide drill, but dont let it exit the other side yet. Do all the holes that way, then use a hard steel bit to finish up. The carbide bit breaks too easy, but the hard steel bit is more flexible so it doesnt break as easy once it comes out the other side of the work piece. It takes a little practice to know when to stop with the carbide bit however, but probably any time after it gets through the top copper layer of a single side board is good enough. A double sided board is a little harder to do because the hard steel bit has to go through another layer of copper. So if using the carbide bit for that too it helps to drill part way though anyway and then later finish up with the carbide bit, the second pass you will have a better grip/angle and it wont break as easy. Still the hard steel is better for the second pass if you can get away with it with double sided boards.

 

[Blueteeth]

Wow, nice tips there MrAl (as always!). I can't help but feel that doing 'two runs' of drilling holes on say... a eurocard size board (160 x 100mm) would just double the tedium.. although as you pointed out, HSS bits quite easily flex and find the hole centre on their own (when letting the PCB move a little horizontally) - so I guess the second pass would be very quick indeed.

I much prefer HSS bits, they are so cheap anyway, £2 for 10 on ebay, that I actually end up using those more often, even on double sided FR4. I just throw them away once the tone of the drill changes as it bites into a new hole.

But back on topic. All the above suggestions really do rely on a very accurate and sturdy press. Perhaps 'precision' is the wrong word to use as that implies automation (like CNC's) but every press I have used/tested has had mroe than enough slop to send a shard of carbide bit through my fingers (whilst costing me a couple of quid). >0.5mm slop is unacceptable for PCB, regardless.

My current PZ541 is rather tight at the top of travel, gradually getting more 'lose' at the bottom, to the point where I can wiggle it around 1mm. With drill vibration, I can never predict exactly where the drill will land - I am of course going to attempt to service it, by drilling out rivets and adding bronze shims.

The simplest and (by review) most accurate and reliable one I've seen is the stand for the dremel 300 sold form MEGAUK https://www.megauk.com/pcb_drilling_machines.php - top. The idea of pillars as guides such as this and used in Z-axis of CNC machines appeals to me, over other guides as its relatively simple. Linear bearings are cheap enough, but probably not necessary. The only trouble here would be machining the metal blocks that hold the guides (bottom, and top for rigidity), but even those can be purchased premade. It seems a DIY one can go as simple, or as complicated as one likes!

 

[BobW]

I found that a Dremel or similar tool is too heavy and badly balanced for handheld use, and that any kind of drill press arrangement makes it awkward to quickly line up the drill with the position on the board needing to be drilled. In fact I find that the use of any kind of drill press gives you a lot less feel for the amount of pressure you're applying, and can lead to drill breakage.

Years ago when our drafting department was throwing out a bunch of cordless electric erasers, I took one home and fitted a small drill chuck to it. I've been using it ever since for PCB work. It's handheld (you hold it like a pen), lightweight, well balanced, and has enough torque for drilling PC boards. Once set up, I can drill holes as quickly as one per second. As Crosslakeguy mentions, the drill will follow the etched centre hole of the solder pad, so there's no need for the precise alignment capabilities of a drill stand. I don't think I've ever broken a drill with the modified eraser, but I don't use carbide, just HSS.

 

[Mr RB]

This is the same drill press as mine (ignore the $78 ebay price, I paid about $19.95);

**broken link removed**

All the grey bits are cast metal, and the sliding up/down bit when drilling is on heavy plastic/metal bushes that has no slop.

The small ring attachment was perfect for glueing in a small DC microtool.

Even if you buy a different type and it has some slop, it's very easy to diagnose and remove the slop by making some mods.