routing an bell cable throught cavity wall

[tinpan]

I know this sounds daft but how do I drill through 4" brick then 4" air gap then 4" thermalite block, all in one neat and tidy operation, so you can see thro the small hole to the outside and easily feed a small cable? The masonary drills only come in at about 8".I wish to fit a bell box outside without showing the cable entry.Is there a very long masonary drill out there?
rgds.
tinpan

 

[BS3036]

You could look at core drills. Screwfix for example. You should use a drill with a clutch though, to avoid breaking your wrists.

The bit itself may not be that long, but an extension arbour deals with that.

 

[Chri5]

http://www.screwfix.com/prods/17627...s/Masonry-Drill-Bits/Masonry-Drill-12-x-400mm

 

[roberta1000]

Every tradesman I know has a selection of drill bits 450mm-600mm long for exactly that. Any decent tool supplier sells them. As partly mentioned above take it easy, make sure you keep the drill square to the hole, clear the hole regularly and be ready for it snatching if it jams.

For feeding the cable if it is soft enough to droop into the cavity, get a wire coat hanger, straighten it out, make a hook in one end and crimp onto the cable then pull through.