"AncelB
mosaicmerc@... [Homebrew_PCBs]"
> I use resharpened carbide in my dremel 395 with 1/8"
shanks for PCB
> work. They work fine....I go down to around 0.31 mm. I
can go smaller
> but bit breaking happens every 10 holes or so.
>Me too, but I rarely break bits since I switched to a home-brew
drill
stand that seems to eliminate any "hand wobble" from causing breakage.
>My CNC machine can drill lots of holes with resharpened carbide and
a
Grizzly pencil-style die grinder.
>Perhaps rigidity in the holding of the dremel is more important
than
runout? Or at least, ∗lack∗ of rigidity is more common as a cause of
breakage?
href="mailto:dj@...">dj@...>
I purchased a drill stand from Sears quite a few years ago. It
had run-out, but I cured that by tightening/adjusting all the
critical screws that caused the run-out. Works just fine since
then, and no breakage of carbide drill bits either. I'm using
a Dremmel with the collets, mostly the 1/8" size. I gotta say
though that the stand sure is CHEAPLY made....lots of plastic
parts. Once when using the stand, the sector gear that raises/lowers
the drill carriage broke!! (Cheap plastic!!!) I made another gear out
of some thick aluminum and it's been good ever since.
My bigest problem is positioning the PC board on the exact
center of the pads. My drilling is close but most of the time not
dead-on especially if the pad's center holes don't get etched
away. I installed a 12v light bulb under the stand and
that helps to illuminate the pad locations, but still.....
On my drill stand I made a larger platform out of some
1/8" smooth hardboard so I could use a homebrew
moveable fence that clamps to the edges of the hardboard.
Using that sure made drilling easy when I needed to neatly drill
holes in a row like for IC's.
Charlie