Drill bits for PCBs

[ilovetherat]

Hello again,

I was wondering if anyone knows what size drill bit I should use for drilling my PCBs?
Also I was where is a good place to buy drill bits for PCB drilling?

Thanks for your help!

[alparent]

http://www.leevalley.com/wood/page.aspx?c=1&p=41754&cat=1,180,42240

[KazooMan]

I like these from Small Bear.

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

The larger shank is easier to align in the drill chuck and the shorter actual drill portion doesn't break as easily as regular bits.  Also, the shank is the right size to grip in the smaller Dremel tool collet.  I usually have one handy to drill out the one or two pads I missed, to enlarge a hole if a component has an unusually large lead, or to redo a hole after unsoldering a component.

The only downside is that they are expensive.  Worth it in my opinion.

[John Lyons]

http://drillcity.stores.yahoo.net/10pacresdril.html
.035 works for everything I do.
Look for the resharpened carbide 10 packs.
Super price, fast shipping.
These last me fora few thousands of holse

[ilovetherat]

Thank you all very much!!! super helpful!

[jrem]

drill bit city, #68 (0.031"), a dremel, and a dremel drill press.  Works great after you get the hang of it.

[Taylor]

My favorite is an engraving bit. After breaking tons of regular bits, I tried this out, and it works perfectly and hasn't broken after many boards. The downside is that I couldn't find just one of these at Lowe's, so I had to get a whole pack of random bits for a Dremel.

[Brymus]

http://drillcity.stores.yahoo.net/10pacresdril.html
.035 works for everything I do.
Look for the resharpened carbide 10 packs.
Super price, fast shipping.
These last me fora few thousands of holse

Cool,thats where I am getting mine from,nice to know they are good.

[deadastronaut]

if in uk...uk drills...10 x 0.6mm for 3quid!................bargain..........!!!!..

[R.G.]

There is a technically correct answer, and a good enough answer. The technically correct answer is that the finished hole needs to be about 5-8 mils (5/1000 to 8/1000 of an inch, 0.127 to 0.2mm) bigger than the lead that's in the hole. This is to ensure best solder connection between pad and lead.

However, almost all the leads used in effects can work fine in a 0.030" / 0.762mm hole. The range is usually 0.025"/0.635mm to 0.050"/ 1.27mm, although the bigger holes are primarily for wire leads and big-lead power diodes like the 1N400x series. If I had to pick a single drill size for PCBs, I'd use something between 0.03" and 0.04", 0.762mm to 1.016mm. That works well for almost all of the small signal stuff used in effects.

High speed steel drill bits are only good for about 50-100 holes in glass-epoxy PCB stock before the glass fibers dull them too much to use any more. Carbide bits can go thousands of holes in glass epoxy if you don't break them. They break if you even think of drilling with any wobble or not in a straight line.

[SpencerPedals]

My favorite is an engraving bit. After breaking tons of regular bits, I tried this out, and it works perfectly and hasn't broken after many boards. The downside is that I couldn't find just one of these at Lowe's, so I had to get a whole pack of random bits for a Dremel.

I use a dremel with the engraving bit exclusively and love it.  It's very pointy but doesn't ever give the impression it will break.  And if you end up using some random thick-lead component, you can adjust the hole to taste easily.  I wear leather gloves and drill the holes freehand using that in the dremel, wearing a respirator, of course. 

[Dan N]

I use these:

http://shop.vendio.com/MoranEnt/item/557876442/index.html

[John Lyons]

Yowza! Some great deals there.

[jamiefbolton]

so what if i'm drilling by hand with a standard drill. bad idea?

[R.G.]

so what if i'm drilling by hand with a standard drill. bad idea?

Not a bad idea - just not what you'd do if you had another choice. Standard drill bits are probably High Speed Steel (HSS) and will get too dull to give good holes with clean edges and not pulling copper loose, leaving ridges, etc. in 50-100 holes. That's fine if you have a full pack of them. If you're going to do this, get a lot of them and consider each hole costing 1/100 of a drill bit. Standard drill - which I'm taking to mean a variable speed corded or cordless - is OK, but will not turn fast enough for best cutting on glass-epoxy board stock with tiny drill bits. Your lightest consistent pressure is probably too much for good cutting, and makes the bit take too deep a bite for the slow rate it turns.

On the other hand, you *will* wobble around with a hand-held bit, and HSS bits will bend (some) and will last longer than carbide in a hand held drill. Carbide snaps off with any misalignment. I'm lucky to get four holes in a row hand held with carbide. But in a press, carbide lasts for thousands of holes, unless I press it too hard or run it too slow and break it.

So if you have to have a PCB, and all you can get to drill with is a hand drill, use HSS and get a lot of them, preparatory to throwing them away after 50 holes or so if you want quality holes. If you can get a press, Dremel or otherwise, use solid carbide bits. I've never actually dulled a carbide bit.

[jamiefbolton]

how much is a drill press. i've seen them around $200. that's a bit steep for a pedal hobby

[Scott57]

how much is a drill press. i've seen them around $200. that's a bit steep for a pedal hobby

Like everything else, that will depend on make, quality, features, etc...

A table model can be as low as $70.00:

http://www.harborfreight.com/garage-shop/stationary-drill-press/5-speed-drill-press-38119.html

I have this one, which can be had under $100.00:

http://www.sears.com/shc/s/p_10153_12605_SPM249424846P?prdNo=14&blockNo=114&blockType=G114

[R.G.]

how much is a drill press. i've seen them around $200. that's a bit steep for a pedal hobby

How much is *one* boutique pedal?

[jamiefbolton]

ok good point RG. what about getting a dremel and the drill press attachment? seems like that could be a good idea. i'd get to buy a rotary tool and i'd get to have a drill press too. can the dremel drill enclosures? and drill other things that you would normall use a drill press for? ie wood working