carbide PCB drill bits

[evandude]

I just wanted to point this out for anyone who makes their own PCB's...

**broken link removed**

$14.50 including shipping for a pack of 50 carbide drill bits, and you can mix and match from a pretty big list of sizes! (up to 1.15mm, so good for MOST components)

i already have a personal collection of about 80 carbide PCB bits but it's tempting to get some more at that kind of a price!

 

[zachtheterrible]

Wow! Thanks for sharing Evan. I think I might get me some of those.

I would like to get most of the same size. I know I won't be needing all the same size because I've been using a SINGLE drill bit from a hobby drill to drill my PCBs. I've drilled about 5 seperate PCBs with it!

Could anyone suggest a few good sizes for me? Thanks.

 

[evandude]

0.70 mm is perfect for most small leads (IC leads, small transistor leads, resistor and capacitor leads, etc)

1.00 mm is perfect for most other reasonable-sized stuff (larger transistor leads, like TO-220 case, and pin headers and stuff)

I wouldn't highly recommend getting many below 0.70mm because they will be extremely fragile (and 0.70mm is pretty small as it is)

but I'd suggest those two sizes, and some in between, and maybe snag a couple each of some of the largest sizes too.

and I sure hope you have a drill press :lol: carbide bits are awesome in that you can drill thousands upon thousands of holes without them going dull, but if you so much as THINK of applying a side force to them, they'll snap like a twig.

 

[zachtheterrible]

thanks evan, yeah i do have a drill press. i used to drill my PCBs with a hand drill!

 

[adamthole]

Thanks alot, that is a really good deal. On a side note, what is the secret to drilling with carbide bits? My Dad had a set of ten, and I broke two of them before I finished drilling 1 board. I was using a drill press and I had the PCB sitting on a block of wood. Should I be drilling it on something besides the wood?

 

[evandude]

wood is fine... but one thing you have to focus on is not allowing the board to move at all when drilling... I broke some bits when I first started because i let the board slip a little when drilling... you have to hold it securely.

also, it does require the drill press to have a decent spindle... if it is wobbly or otherwise unsteady it will break bits. the drill press I currently have is a dremel attachment, however it is almost worthless because it is rather poorly made so it deflects noticeably when going up and down, and is just generally unsteady. I just ordered a higher-quality drill press stand from minicrafttools.com, I can't wait to get it.

also, you need to try to run the bits at high speed. you have to remember, these bits were run at like 60,000 to 120,000 RPM's on high-speed drills when they were used in industry, so they are not designed to run at low speeds. the dremel is capable of 30,000 RPM's, which is a lot better than the 2,000 or 3,000 RPM's you'll get out of most regular drill presses. I have noticed that at the speed of the dremel, the bits go through the board like butter, and don't break from non-sideways forces, whereas with the regular drill press I used to use, they would sometimes just break randomly during normal drilling even when I was careful about side forces, due to the low speeds.

 

[GatorGuy]

Thanks alot, that is a really good deal. On a side note, what is the secret to drilling with carbide bits? My Dad had a set of ten, and I broke two of them before I finished drilling 1 board. I was using a drill press and I had the PCB sitting on a block of wood. Should I be drilling it on something besides the wood?

Are you holding the block of wood? Even the slightest side pressure can break small bits. There are clamps that you can get for drill presses that will hold the item that you are drilling. Some even have knobs to adjust the position of the item to be drilled.

 

[Dean Huster]

I've always used the Dremel drill press accessory with no problem. The trick is to lower the head down until the bit is about 1/8" above the PCB. The less you lower the "quill", the less slop there will be. I rarely break carbide bits, but I do wear them out. Whenever the material drilled from the PCB mounds up around the bit (like using an auger to bore post holes) rather than the chaff just flying off, it's time to replace the bit. Dull bits don't let the material fly.

Also, be sure that you're using the Dremel at a high RPM. It doesn't have to be at the max, but pretty high up. And never use the 3-jaw chuck accessory for the bits. Use a standard 1/8" collet because it runs so much truer and will cause less breakage.

I have my press mounted at the very front edge of a taller bench with a short stool so that my face is right at the drilling plane when I'm seated. Then a lighted magnifier is pulled in front of the bench between my face and the drill bit. Serves as light, magnifier and eye protection all at the same time. I also have a boxer fan on one side of the press to blow the "chips" away as they come out, leaving the PCB clear and easy to see.

Dean

 

[evandude]

but you must have one of the older dremel drill presses. previously their presses were made by another company and simply branded as dremel. now they make their own (as of their model 220 work station/drill press)

due to my complaints and similar complaints of others, they have taken the model 220 off the market to re-engineer it.

it was horrible, mostly plastic, and had a horrible actuator system. I'm now a beta tester for the replacement model, so i'm pushing them to go with a rack-and-pinion system like they should have done in the first place. we'll see how that works out, they say a new model should be available around the end of the summer.

 

[zachtheterrible]

Ouch, i guess my drill press will not work. It's a really cheap one that i got from Harbor Freight. I think it was around $60. What do you suggest that I do to make it work with the carbide bits?

 

[evandude]

it will work, I used my regular 70-lb tabletop drill press for around a year. just make sure you run it at its highest speed, and when you drill, don't force the bit down hard, just go down softly so you aren't applying much force to the bit, and let it work its way through... at 30,000 RPM's the bit drills quickly enough that you don't have to worry about that, that's the big difference.

yeah, you'll occasionally break one, however at a price of $15 for 50 bits, you can easily have enough bits so that when one does break or dull, you're only out a few dozen cents 8)

I've made dozens upon dozens of boards, and so far have only broken 5 bits (all of them were very small ones, and all but one of them was broken in a period of about 10 minutes when my dremel drill press was REALLY not cooperating... the other one was broken when i was taking it out of the chuck and I hit it with my thumb :lol: but never broken any others during drilling, and never had any go dull)

 

[zachtheterrible]

Cool! ill go ahead and get those.

 

[adamthole]

I ordered some also, thanks!

 

[bryan1]

Eh Zach,
Why not design and make up a small purpose drill for those drills. All you need is a decent dc motor with high rpm and a resonable amount of torque and get an adaptor machined up to take a 1/8" collet chuck. It won't be hard to make up the machine it's self but if you need a hand I can draw up one for you. But if you scrounge around for a rack and pinion your 1/2 way there. Running small carbide bits under 25,000 rpm will either break them or blunt them very quickly, and if you put ya mind to it use a couple of steppers and make up a cnc pcb drill.

Just sing out if you need a hand

Cheers Bryan

 

[evandude]

not that having a CNC PCB drill wouldn't be nice...

but you can buy a dremel for like $50 (or a dremel clone for even less)
and a good drill press stand for it for $55 and not have to build anything yourself. and i'd hardly count the cost of the dremel against it, because it is probably the most useful power tool in the world so you can get plenty of use out of it for other things as well

not everyone has the machining equipment to be making a drill press with rack and pinion assembly and collet and all that, and make it actually turn out decent :roll:

 

[zachtheterrible]

Eh Bryan, i think that would be waaaay over my head :lol: