On Sat, Aug 11, 2012 at 9:10 AM, Herb Schoenbohm <herbs@vitelcom.net> wrote:
> When drilling in stone to prevent overheating of the drill bit and tip
> consider using water as a coolant.
>
You have to be careful doing that. Some types of carbide will instantly
crack from the thermal shock of cooling too fast. It's better just to
retract the drill a lot so that the grooves in the drill bit don't plug up;
that's what generates a lot of heat.
The other thing that came to mind was to use a curved piece of pipe or
tubing as a water drill. One end open, the other end hooked to a garden
hose. The radius would have to be fairly constant in order not to bind in
the hole.
Hey, you could put a gopher in a bottomless cage on one side, and some food
on the other. When he burrows under the wall to get at the food, you can
run your radials through his burrow. ;-)
Seriously, will it really matter if we run it up 48", over 24", and down
48"? Maybe it would if we wanted to use the radials on higher bands, but on
160? Just parallel some wires like Tom suggested, to keep the inductance
down.
I don't think we even know how far from the vertical the wall is. If the
wall is short enough, far enough away, and/or at angle, a few radials bent
or missing in the direction of the wall might not even matter.
73, Mike
www.w0btu.com
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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