h a l f b a k e r y
Replace "light" with "sausages" and this may work...
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It is often necessary to drill a hole in something using an
electric drill. Moreovermore, it is often desirable that the
hole should be perpendicular to the surface. Ensuring this
perpendicularity, however, is not straightforward.
One solution is to use a bench drill (which lowers the bit
vertically onto the workpiece), but this is not much use
you want to drill a hole in a wall, an okapi, or some other
thing too large to fit under the bench drill. For hand-held
drills, the best you can do is to look at the angle of the drill
from above/below and left/right, and try to keep it all
as you drill.
Howevertheless, a simple solution suggests itself, involving
lasers. One low-power laser, with its beam split into eight
parts, should be sufficient. Just arrange it so that the beam
split into four pairs of beams (one pair above, one below,
to the left, one to the right), wherein each pair of beams
converges. For example, the top pair of beams will start out
two inches apart, but converge to be only a quarter of an
apart a few inches in front of the drill chuck.
Now, it becomes easy to hold the drill square-on to the wall
just tilt it up/down until the two dots above the drill have
same spacing as the two dots below. Likewise, tilt it
until the two dots to the left have the same spacing as the
to the right. The same setup will work regardless of the
length of the drill bit or how far into the wall you've drilled.
[Some time later... use a circle of laser light instead - much
[xaviergisz, Nov 15 2018]
Spinning laser center finders
Shown by Dan Gelbart in one of his videos in 2013, since built by many people [notexactly, Dec 03 2018]
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||I think you could get away with 3 pairs, at 120 degree
||Interferometry would be more precise.
||Or since you're spinning a motor, put the laser on the
spinny part at a pleasing angle. (Balance the weight
out, too). Or maybe just a spinny mirror.
||//3 pairs, at 120 degree intervals.// You could, but I think it
would be fiddlier to use, since pitch and yaw movements
would be interlinked. Easier to have one pair for pitch, one
||//Interferometry// In what way? If it gives a big response to
very, very small movements it might be too sensitive for a
||Actually, hang on a moment. Forget the paired beams. Just
have a lens that projects a circle of laser-light around the drill
bit. If the circle is an ellipse, you're off.
||That brings up an interesting point on judgment. I
suspect we can better tell simple distances as a
comparison between points than the ovality of an
oval, even though the oval would contain every
||The interferometry of course would be an appeal to
our halfbakery nature for overkill.
||I just did a quick test in Illustrator, and it's very easy to tell a
30mm circle from a 28x32mm ellipse. You can even see that
a 29x31mm ellipse isn't quite right.
||Somebody who knows geometry should be able to tell me how
many degrees error that equates to.
||Looks like such a good idea that its baked.
||Well, damn. BullseyeBore is exactly this. Sadly not available
for purchase yet, though.
||There are drills with spirit levels built-in... not too difficult to imagine one with angles as well (for surfaces with a definitive idea of up and down, of course).
||Alternatively, a rectangular body drill : square up to the hole with a piece of accurately cut angle-iron.
||Wouldn't a drill with massive gyroscopic fly wheel built in do the job perfectly?
||// pairs of beams ... wherein each pair of beams converges //
||Will this allow you to maintain exactly sixty feet above a German reservoir, at night ?
||Having a massive flywheel on the drill might make
drilling tight spaces challenging.
||This boring idea and the link are much better than
my solution which is to affix a grinding disk to the
base of the drill. I would drill the hole at any old
angle then continue on until the grinding disk
FORCES the surface in question to conform to
perfect perpendicularity to the hole just drilled.
||There 'are' drill plunger attachments which will let you align to whatever angle you wish... if it isn't a Mandela effect thing.
||A tiny stick on filter to the drills light (a feature on newer battery drills) would supply the circle needed. The circle doesn't have to be at the drill point. It could be even be an oval that when orientated correctly displays round.
||BullseyeBore claims to have patents granted and pending.
However, spinning laser center finders have been baked and
WKTE since at most (because that really makes more sense
than 'at least') 2013: [link]