On Sat, Aug 11, 2012 at 9:10 AM, Herb Schoenbohm <[email protected]> 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 _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
