drill sizes

[jrem]

hey, what diameter drill are you all using for pc boards?  I have a 0.037" and it tears the trace pads off the boards, it's pissing me off.

thanks, John.

[5thumbs]

I usually use a #60 (0.04") drill bit on PCBs.  I do a couple of things to make drilling pads a little easier.  First of all, I use a small finishing nail as a micro-sized center punch.  I use it with a hammer to gently tap in a dimple in the middle of the pad.  This allows the drill to grab the dimple and not "skate" around so much on the copper.

Next, drill speed is important.  When I'm using the 1/2hp drill press in my shop, it starts holes more quickly and easily than my 1/3hp indoor press.  The max speed on the 1/2hp press is around 5400rpm, where as the 1/3hp press only does 3700rpm.  With the faster spin speed, using the micro-sized center punch is optional (but still helpful.)  With the slower spin speed, use of the center punch is essential to get a reasonable hole drilled.

Finally, drill bits do get dull and could be contributing to your tearing problem.  I tend to swap bits when they start skating excessively, so I've never used one to the point it might grab the copper and tear off the trace.

Not sure if that helps, but hopefully it does. 

[jrem]

nah, what I'm looking for is what size bit to drill through the ggg layouts, like bsiab2 and eat . . .    without tearing up the pads.  I've been using an 0.037" bit, and drilling before etching, which tears up some of the resist, but then I hit it with a sharpie, then etch.

I'm pretty sure I've read others etch then drill, and if so, how do they keep from tearing the pads off the board?  I'm also using a hand held dremel on high, 10,000 rpms or so, with a brand new bit.  I think I need a smaller bit, one that won't cut so much copper.

[Zben3129]

www.drillbitcity.com


http://www.drillbitcity.com/catalogue/product_detail.asp?Tg=101-10W69-60   


to be exact.

Thats what I use...big shank (1/8?) so useable in pretty much anything.


I started on the dremel, but I am not the steadiest person in the world. If you dont wanna break 3 bits per board, get a 70 dollar table drill press



thats .02

[5thumbs]

nah, what I'm looking for is what size bit to drill through the ggg layouts, like bsiab2 and eat . . .    without tearing up the pads.  I've been using an 0.037" bit, and drilling before etching, which tears up some of the resist, but then I hit it with a sharpie, then etch.

I'm pretty sure I've read others etch then drill, and if so, how do they keep from tearing the pads off the board?  I'm also using a hand held dremel on high, 10,000 rpms or so, with a brand new bit.  I think I need a smaller bit, one that won't cut so much copper.

I etch before drilling as well.  I've switched to not putting a hole in the middle of my layout pads anymore (at least on the layouts I do just for myself.)  Pad holes were enlarging during etching, sometimes more than I wanted.  By leaving the blank, copper pad and drilling the holes through it, the copper comes right up to the edge of the hole.  So, even with the slower RPM presses I use, I'm drilling through the copper pad circle and not having any tearing issues.

But I'm overlooking a big difference in our approaches.  I'm using a slower-speed drill press and you're using a Dremel tool.  That might be the difference.  Perhaps someone who is using a Dremel tool with the Dremel drill press thingy could comment about their experience in this area.

Sorry I couldn't be more help.