[sdiy] Hunk o metal

[Altitude]

As far as center punching goes, I would recommend against it since it can
hop around a lot depending on how perpendicular you are to the surface when
striking it.  If I want a very tight alignment, I use a layout dye (Dykem
Blue etc).  This stuff dries fairly thick so when you scribe your layout
lines, it leaves nice channels to the point where you can feel the
intersections when you follow them with a sharp point.  From there, just
leave a tiny handmade pilot (i.e. punch hole) at the crossings so you can
accurately follow up with a VERY small drill that leaves a much more
accurate pilot to start with an even larger drill.  Then just work your way
up.  Do not use 135 split point drills, just the standard 118 deg points,
they do not jitter nearly as much.  Once you get to ~5/32" hole size, you
can go to something like a step drill (Unibit) that can make short work of
thin material.  I like the unibits since you can easily deburr the hole by
slightly touching the next size up which leaves a nice small chamfer.
Decent cutting fluid is a big plus also (I seem to use Tap Magic for
everything)

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Matthew Smith
Sent: Thursday, February 03, 2011 8:31 PM
To: Speth, John
Cc: sdiy DIY
Subject: Re: [sdiy] Hunk o metal

Quoth Speth, John at 04/02/11 11:49...
...
> As for drilling, I'd love to hear the answer from experienced 
 > builders.  I'm about to drill a panel with some 30 holes
 > and I don't to screw it up.

Biggest issue would probably be alignment. I'm *not* a metalworking 
guru, but I'd scribe up a grid using a decent square, double-check the 
measurements and then centrepunch all the drill points first.

Ideally, if your equipment is big enough, get the panel onto an X-Y 
table/vice or clamped to something that can fit in one so you can feed 
along a row of holes, rather than positioning by hand - which always 
ends up with things a bit out of kilter for me.

Life is hard, for those of us without CNC mills ;-)

-- 
Matthew Smith

Blog: www.smiffysplace.com  Business: www.smiffytech.com
www.linkedin.com/in/smiffy  www.flickr.com/photos/msmiffy
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