# Wall cavity drilling



## besc (May 16, 2010)

I'm adding receptacles, 12 inches off the finished floor. Going under the house with romex. After cutting the hole for the box I want to drill down and feed romex up. With the less than four inches wall cavity space I'm having trouble drilling strait down. My flex bit doesn't flex enough and my spade bit with extension of course wont flex. Any products out there for this I'm not aware of. Thanks. Mike.


----------



## MechanicalDVR (Dec 29, 2007)

Are you using the angle device for the flex bit?


----------



## 99cents (Aug 20, 2012)

Can't you drill straight up from below? Just avoid drilling through the cork flooring. I know a guy who knows a guy who did that once.


----------



## Majewski (Jan 8, 2016)

I use Milwaukee angle drills with all sorts of quick lock extension bits. Otherwise drill through floor with a hanger and measure off of it.... I've been lucky enough to never need more tactics(knock on wood).


----------



## backstay (Feb 3, 2011)

besc said:


> I'm adding receptacles, 12 inches off the finished floor. Going under the house with romex. After cutting the hole for the box I want to drill down and feed romex up. With the less than four inches wall cavity space I'm having trouble drilling strait down. My flex bit doesn't flex enough and my spade bit with extension of course wont flex. Any products out there for this I'm not aware of. Thanks. Mike.


I put the top of the box at 16 inches. Then the flex bit works fine. The 1/2 bit is more flexible, or is that what you're using? Also, Rack A Tiers has a ball that centers the bit.


----------



## besc (May 16, 2010)

Would like to avoid drilling pilot holes in floor as a guide but have done this. I will look up those angle bits though and see if that helps. Thanks guys.


----------



## besc (May 16, 2010)

Not familiar with Rack A Tiers


----------



## 99cents (Aug 20, 2012)

besc said:


> Would like to avoid drilling pilot holes in floor as a guide but have done this. I will look up those angle bits though and see if that helps. Thanks guys.


I might try a long 1/8" bit on an extender to drill your pilot hole, then drill with your auger bit from below.


----------



## MechanicalDVR (Dec 29, 2007)

Try this with a 1/2" bit:


----------



## drewsserviceco (Aug 1, 2014)

1/8" bit in floor or shoe molding looks like a finish nail hole. I have the kit with assorted colors of wax filler in the truck for tricky situations. 

You situation shouldn't be too tricky, just means you'll have to go in crawl space twice instead of one and done. 

You can probably see the spikes holding the bottom plate down from the crawl space. That's when you know your in the right neighborhood.


----------



## backstay (Feb 3, 2011)

I have this tool. You set it on the floor and go in the crawl space to locate your spot. It works great, one trip, no pilot holes to fix. 

http://www.firsteditionproducts.com/drillspotter.html


----------



## backstay (Feb 3, 2011)

Here's the target that would go on the floor. It works on a ceiling or wall also.


----------



## macmikeman (Jan 23, 2007)

Every year I race to the tree early early on December 25th and frantically dig and grab about looking for my drillspotter but sadly it never came and I only found coal.


----------



## EC2253 (Mar 7, 2008)

Drive a 6 penny finish nail at an angle right at the edge of the trim board below where you want the outlet. Use the angle of the nail below move over 2 inches and drill up.


----------



## HackWork (Oct 2, 2009)

I have done this both ways. The 1/2" and 9/16" 4' long flex bits bend a bit easier than the larger size. With the placement tool you can get it to drill straight down thru the bottom plate.

But I find it easier to drill a small hole thru the floor or shoe molding and stick a piece of stainless tie-wire thru it to find underneath. This is one of the 20 different things I use a 12" piece of stainless tie-wire for and why it's in my service tray all the time.


----------



## jw0445 (Oct 9, 2009)

My method is to screw in a shiny 3" drywall screw at the wall edge. Easy to spot from underneath.


----------



## besc (May 16, 2010)

This is all awesome stuff guys


----------



## MechanicalDVR (Dec 29, 2007)

jw0445 said:


> My method is to screw in a shiny 3" drywall screw at the wall edge. Easy to spot from underneath.


Doesn't this make a larger hole and dimple to fill / patch afterwards?


----------



## Majewski (Jan 8, 2016)

backstay said:


> I have this tool. You set it on the floor and go in the crawl space to locate your spot. It works great, one trip, no pilot holes to fix.
> 
> http://www.firsteditionproducts.com/drillspotter.html


Oh great, more things I want to spend money on! :thumbup:


----------



## readydave8 (Sep 20, 2009)

MechanicalDVR said:


> Doesn't this make a larger hole and dimple to fill / patch afterwards?


Probably so in hardwood floors.

Works great with carpet, stay hard against wall to keep from carpet twisting up on screw, disappears and does not need to come back out


----------



## Majewski (Jan 8, 2016)

I've never done that Dave, but now I want to.


----------



## telsa (May 22, 2015)

I shun flexi-bits -- and so I'd rather make a pumpkin cut into the drywall -- and let rip as if the stud bay was fully open.

1) It's fast.

2) Pumpkin cuts are EASY to repair with a touch of mud.

Jump to 3:00 minutes in.






Jumping back and forth from the crawl space to the conditioned space -- makes for a very tired electrician. (me)

3) This technique does not require any additional trick tools.


----------



## HackWork (Oct 2, 2009)

That's silly, why would you make an additional hole in the wall when there are so many good alternatives?


----------



## telsa (May 22, 2015)

Repairing a pumpkin cut is CHEAPER than running up my tab.

CS will back me up on this one.

If lath & plaster is involved -- I would shift gears.

But, L&P is a rare beast around these parts.


----------



## HackWork (Oct 2, 2009)

In the time it took you to make that DIY "pumpkin cut", I could have had the hole drilled perfectly to the basement/crawlspace. Or, for those who can't use flex bits, I could have drilled a tiny hole in the floor or molding and sent down a piece of tie-wire to find.

I can't see cutting a hole that needs to be patched and painted for no reason.


----------



## MechanicalDVR (Dec 29, 2007)

readydave8 said:


> Probably so in hardwood floors.
> 
> Works great with carpet, stay hard against wall to keep from carpet twisting up on screw, disappears and does not need to come back out


I've always used some type of wire or rod that was less than an 1/8", never thought about using a screw or a nail (as someone else posted) for that matter.


----------



## drspec (Sep 29, 2012)

I use insulation hangers......they're cheap and stiff.....cut an angle on one end, insert on drill, pry shoe molding away from baseboard and drill.

Easy to find in the crawl and a perfect reference point to drill up into the cavity.


----------



## papaotis (Jun 8, 2013)

on reference holes i use a piece of 12 copper, 1/8 bit. it takes some practice to use a screw though carpet depeding on the type of carpet, a screw will often grab a thread and just keep pulling till theres a hole in the carpet!


----------



## A Little Short (Nov 11, 2010)

backstay said:


> I have this tool. You set it on the floor and go in the crawl space to locate your spot. It works great, one trip, no pilot holes to fix.
> 
> http://www.firsteditionproducts.com/drillspotter.html





backstay said:


> Here's the target that would go on the floor. It works on a ceiling or wall also.


I have that and it works good. Except...................................
IT doesn't work on/through metal!



macmikeman said:


> Every year I race to the tree early early on December 25th and frantically dig and grab about looking for my drillspotter but sadly it never came and I only found coal.


Santa keeps them here!

http://www.firsteditionproducts.com/drillspotter.html


----------



## HackWork (Oct 2, 2009)

A Little Short said:


> I have that and it works good. Except...................................
> IT doesn't work on/through metal!
> 
> 
> ...


So that will work thru an old 20" foundation? Thru a plaster wall (hollow in between)?


----------



## A Little Short (Nov 11, 2010)

HackWork said:


> So that will work thru an old 20" foundation? Thru a plaster wall (hollow in between)?


Yep!


----------



## HackWork (Oct 2, 2009)

A Little Short said:


> Yep!


That's awesome.

But it's one of those things I would like to try out in real life first before buying. Just like the circuit mapper.


----------



## jw0445 (Oct 9, 2009)

MechanicalDVR said:


> Doesn't this make a larger hole and dimple to fill / patch afterwards?


Not really. I don't like patching. If it's a nice finished hardwood floor with no shoe molding I take a look on the other side of the wall. If it's the same I start measuring and looking for nails of the bottom plate from underneath.


----------



## HackWork (Oct 2, 2009)

jw0445 said:


> Not really. I don't like patching. If it's a nice finished hardwood floor with no shoe molding I take a look on the other side of the wall. If it's the same I start measuring and looking for nails from underneath.


I've been there, perfect hardwood floor on each side.

That's when I just drill down.

I have been using the Greenlee 9/16" 4' long flexible bit for a long time. A while back Klein took over Home Depot and now they make one for sale there too. The shaft is more flexible than the bigger bits. With the placement tool it's very easy to drill straight down. Use the placement tool to pull the auger back to the middle of the bottom plate, then push down with the drill so that the tip of the auger gets stuck into the wood, it will now hold there. Drill down and you're done.

I know people have had issues with flexible bits running in the wrong direction, but in this instance I can't see how that would be possible. You are just drilling down thru a 2X4, there is no where else for it to go unless it completely moves, and you would know that while drilling.


----------



## B-Nabs (Jun 4, 2014)

This and this.


----------



## MechanicalDVR (Dec 29, 2007)

"B-Nabs This and this"

That's when I just drill down.

I have been using the Greenlee 9/16" 4' long flexible bit for a long time. A while back Klein took over Home Depot and now they make one for sale there too. The shaft is more flexible than the bigger bits. With the placement tool it's very easy to drill straight down. Use the placement tool to pull the auger back to the middle of the bottom plate, then push down with the drill so that the tip of the auger gets stuck into the wood, it will now hold there. Drill down and you're done.

I know people have had issues with flexible bits running in the wrong direction, but in this instance I can't see how that would be possible. You are just drilling down thru a 2X4, there is no where else for it to go unless it completely moves, and you would know that while drilling.[/quote]

Not sure how good of a solution that combo would be in this instance the OP is asking about. Having a ridgid auger and solid extension to make the distance through the sub floor wouldn't make it in through a box opening 12" AFF.


----------



## B-Nabs (Jun 4, 2014)

MechanicalDVR said:


> Not sure how good of a solution that combo would be in this instance the OP is asking about. Having a ridgid auger and solid extension to make the distance through the sub floor wouldn't make it in through a box opening 12" AFF.


Well not with that attitude. :jester:


----------



## itsunclebill (Jan 16, 2007)

I use a piece of grid wire cut at a sharp angle. They will usually drill through a 2X and some sub-floor without much issue - cut em to whatever length you need. Playing with placement next to floor trim, between wall and trim, or sharp angle into wall and through floor plate. Cheap and you can mark all the places without having to come up and go under to move a single bit. A dab of filler and a bit of paint in a color matched sample container from the local big box mart (which you ought to have anyway for them little things that just happen) erases traces.


----------



## MechanicalDVR (Dec 29, 2007)

itsunclebill said:


> I use a piece of grid wire cut at a sharp angle. They will usually drill through a 2X and some sub-floor without much issue - cut em to whatever length you need. Playing with placement next to floor trim, between wall and trim, or sharp angle into wall and through floor plate. Cheap and you can mark all the places without having to come up and go under to move a single bit. A dab of filler and a bit of paint in a color matched sample container from the local big box mart (which you ought to have anyway for them little things that just happen) erases traces.


The magic markers they make for furniture repairs are great for small marks. Never thought about the sample bottles due to freezing temps in the work van.


----------



## itsunclebill (Jan 16, 2007)

I typically get a sample bottle (from Homer's or Lowie's) of the colors of the rooms I'm going to be working in if there's a chance that plaster or drywall is going to chip off from cutting in a box, or may need to patch otherwise. I just price them into the job - they're cheap. Keeps homeowner's happy.


----------



## Majewski (Jan 8, 2016)

itsunclebill said:


> I typically get a sample bottle (from Homer's or Lowie's) of the colors of the rooms I'm going to be working in if there's a chance that plaster or drywall is going to chip off from cutting in a box, or may need to patch otherwise. I just price them into the job - they're cheap. Keeps homeowner's happy.


I actually use a little camera thingy from Sherwin Williams and get a paint code, and buy extra in the proper sheen. Charge accordingly for it and end result, none the wiser.


----------



## Going_Commando (Oct 1, 2011)

When blind drilling, the rule to remember is...Fortune favors the bold.


----------



## Majewski (Jan 8, 2016)

Last time I went in blind, I went threw to the exterior.


----------



## MechanicalDVR (Dec 29, 2007)

Going_Commando said:


> When blind drilling, the rule to remember is...Fortune favors the bold.


In the house I had two houses ago I drilled right into the run for the dishwasher. Tore out a nice segment with a 7/8" auger.


----------



## Going_Commando (Oct 1, 2011)

Majewski said:


> Last time I went in blind, I went threw to the exterior.


Caulking is made every day. Good judgement comes from experience, and experience comes from bad judgement.


----------



## Majewski (Jan 8, 2016)

Yup! It was wood siding, I used some nice siding filler, silicone and matched the paint after I filled it and matched the texture.......may have been out of pocket but the learning was priceless.


----------



## MechanicalDVR (Dec 29, 2007)

I was working in the basement of a brand new house, still unoccupied. Saw the cable van behind mine in the driveway. Wasn't five minutes later there was a bang and crack as the lights went out. The guy drilled on center a foot below the meter can and right into the feeder to the panel with a hand brace and long bit.


----------



## Majewski (Jan 8, 2016)

So he's dead now, right?


----------



## MechanicalDVR (Dec 29, 2007)

Majewski said:


> So he's dead now, right?


He was alive when they loaded him in the ambulance, had like streaks on his face and arms, he was standing in mud, not sure how he made it. I went up the stairs and outside at a normal rate, figured it was just going to be a pile of roasted flesh but several guys were dealing with the guy. The brace still sticking out the wall tilted down. The power was still on in most of the first floor.


----------



## HackWork (Oct 2, 2009)

Going_Commando said:


> When blind drilling, the rule to remember is...Fortune favors the bold.


I agree, sex bagel.

But drilling thru an outlet cut-out to me isn't really blind drilling, since you can see it and make sure it's going where it's supposed to.

Blind drilling is when you drill thru a high-hat hole thru multiple joists with a long bit, IMO. That's when you drill thru pipes, or the floor upstairs, etc.


----------

