Making a home brew printed circuit board

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Chucketn

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I have finally succeeded in making a pcbfor my Rotary Table indexer project. Next step is drilling thethrough holes for the components. The component leads range from.020” to .042” Can I use HHS drill bits or should I get carbide?
I have a HF bench model drill press andan X2 mill. Which would be better? What speeds for the dill bits?Any other suggestions/cautions?


Chuck
 
Hi, Chuck.

I've always used HSS. Almost any speed works. Since the bits will be quite small, high speeds are okay. I usually use an old Dremel in its drill press stand, so you can see that really high speeds work.

I'd use the drill press, just because the spindle forces tend to be a bit lighter. You will be drilling a bunch of holes, so take it easy on yourself.

Board material can effect cutting. I've had sparks on a bandsaw when I've been cutting fiberglass boards. Kind of wrecked the blade, too. Phenolic boards are easier on tools. Never had any trouble with drill bits, though.
 
HSS should work, but if you are doing a lot of holes, you might think about some small carbide PCB drills, they will last much longer in fiberglass. If you are using a paper based phenolic board, anything will work, but I haven't seen that stuff available in stores.

Also, for small bits like that, you want speed, usually as fast as you can go.
 
Not sure if the board is fiberglass or phenolic. Package does not say. It's from Radio Shack, labled made in China...

Chuck
 
"Can I use HHS drill bits or should I get carbide?"



Carbide will last longer, and stay sharp longer; naturally.

Here's a good site to buy re-sharpened Carbide bits cheap.:

http://drillcity.stores.yahoo.net/restool.html




{Here's typical speed and feed calculations:

(RPMs) = (3.82) * SFM / Dia.}


{Surface Feet per Minute:

SFM = (.26) * RPM * dia.}


Running the bit too slow will cause breakage.


"A tip for drilling extremely small holes is to drill down to the depth stop, and then move it down a 16th of an inch, and repeat. This ensures that too much metal isn't chewed off too quickly."
 
Back when we used to make and drill our own pc boards, .035 was standard for most components, .025 for ICs and transistors. You can buy .035 carbide and enlarge the few that need to be bigger with a steel drill. Depends how many holes you're drilling, if carbide is worth it. They are brittle; don't drop one on the floor.

There's one pc board we still use, that is predrilled except for one hole they forgot. Every time we make one, the woman who stuffs the boards comes over and asks me to drill the hole. I just use a carbide drill in a pin vise and my fingers; it's faster than walking across the room to use the sensitive drill press. So speed is not absolutely necessary. But if you're using a regular drill press, high speed does make it less likely that you'll feed it too fast and break the drill. With a regular press you can't feel a drill that small.
 
I've made a few homebrew PCB's in the past myself.

The system I found that works the best is a carbide drill bit in a Dremel tool with a drill stand. You can get a much higher RPM than a drill press, and the stand (which was, if I recall correctly only about $30 or so) makes it reasonable to work with. It's not really what I'd call accurate, but we're talking clearance and solder here, not a class 1 fit. The only issue I ran into is that there's not a lot of throat depth. I'd have to go check, but I think 2" or so.

But if you have a Dremel already (and I'm guessing most of us do) it's not a bad way to go.
 
chucketn said:
I have finally succeeded in making a pcbfor my Rotary Table indexer project. Next step is drilling thethrough holes for the components. The component leads range from.020” to .042” Can I use HHS drill bits or should I get carbide?
I have a HF bench model drill press andan X2 mill. Which would be better? What speeds for the dill bits?Any other suggestions/cautions?


Chuck
Click to expand...

Hi,
Make yourself one of these!

http://www.instructables.com/id/PCB-Drill-Press-Using-Salvaged-Door-Hinges/

It works a treat and is much faster than a conventional press. The longer you make the "arms" the better. Mine are about 2ft long and the arc at the tip is negligible for the thickness of a PCB. For the spring I simply use rubber bands between opposite angles of the parallelogram . There is also some lateral movement possible due to the play in the hinges. Very useful!
Martin
 
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