Boring Long Holes in 12x12 beams

[tim walker]

Hi all, we are starting a new house build and have 4 rough cut cedar columns that are 12" x 12" x 6 ft, The intent is to install lights on them. The electric service will come from the ground. The light fixture will be located 4 ft from bottom of beam. Does anyone have suggestions of how to bore a hole 48"? Going from the top is not an option.

One of my thoughts was to split the beam, route out a 1" groove in the middle, then glue and clamp back together.

Any other thoughts or suggestions?

Ashampoo_Snap_Tuesday, March 19, 2019_19h31m38s_009_.jpg

[Tom M King]

I have used a long flex bit. https://www.homedepot.com/p/Klein-To...3751/203872163

But if that starts to go off course, tested with steel rod as you go, I would switch to stiff bit extensions, and a regular electrician's bit, but they can get scary with a possibility of coming off the bit.

[Peter Christensen]

Just route a two step groove from the surface. Put the conduit for the wires in the bottom of the groove and a strip of matching Cedar on the top step glued and fastened in place.

[William Batdorf]

Many times a great effect requires a great effort. Have you considered taking the proper sized bit to a machine shop, having them tig weld on an appropriate extension and then truing the welded assembly on a lathe? The result has no choice but to be nearly perfect if you can guide the bit accurately. A spirit level attached to your drill will help guide the centerline of the hole to right where you want it to be. No need to rip the timber in half.Good luck!

[Phillip Mitchell]

Just rout a groove for the wire on the face that will be the the least visible most of the time, patch the groove thoughtfully and move on. Or you could use it as a design element and incorporate some metal (powder coated black maybe) as a cover for the groove, or use some attractive conduit.

Designers always come up with cocka-mamey ideas like this that make no sense when you think about having to actually execute the design. It's better to embrace what is (wire to a light) and try and turn it into something elegant. Also, you retain access to the wire this way as opposed to burying it in an inaccessible place if you try and go through the middle of the post, though I doubt you'll really need access to all of the wiring anytime soon.

I bid a job once for some (exterior) cedar timber framed light posts that line a driveway. The posts were nearly 12' tall and the designer on the project asked more than once "why could we just drill a hole through the center of the post to conceal the wire??" Clearly, she hadn't actually ever been tasked with drilling such a hole or she would've known better than to ask a question like that

[johnny means]

I would drill a centered hole with a long 5/16" twist bit. I would then chase that with an 1.5" spade bit. I would then add an extension to the twist bit and repeat the process from the bottom of the last hole. Of course, you'd need 4 feet of extensions.

[Geoff Crimmins]

You might be able to do it on a lathe with a gun drill. I don't know if they make gun drills that long though.

[Jacob Reverb]

Just route a two step groove from the surface. Put the conduit for the wires in the bottom of the groove and a strip of matching Cedar on the top step glued and fastened in place.

I'm for doing somethng along the lines of this. Every time I've tried to drill a long hole through something, the results have been far from stellar.

[Bill Dufour]

You might be able to do it on a lathe with a gun drill. I don't know if they make gun drills that long though.

They make them as long as you want. The big battleship guns are about 68 feet of gun tube. Hard to find a lathe that size anymore. Might look for an oilfield lathe to bore yours.
Bill D.

[Sam Puhalovich]

In 1997 I installed a security system and had to drill holes to the windows ... I bought a 1/4" drill that is 53" long ... it was about $17 as I recall.

[Zachary Hoyt]

How about this- a 3/8" x48" drill bit for $33?

https://www.ebay.com/itm/3-8-in-x-48...QAAOSwI3RW-vnA

Zach

[Mark Wooden]

Save yourself time, aggravation and money-
Cut the groove in the back ( I'd use a table saw with a dado head, easy and accurate), cross bore to the fixture location, glue in a matching strip with epoxy, sand flush.
You'll be done in less time than it takes to get a bit to do it.
You may have to rout a recess for an electrical box to mount the fixture, but don't do it until you have the fixture and box in hand- sucks when the wrong box is supplied.

[Roger Feeley]

OK experts out there, I bite. What is it about a gun drill that makes it go straight? They are made to go through metal which doesn't have grain like wood so there's that. But would a gun drill truly go straight for four feet?

I read in Wikipedia that twist drills can generally stay straight for 5 times the diameter.
Are there wood bits out there that are made for drilling deep straight holes?

When I was in Jr. High shop, a popular project was to take an old bowling pin, strip the plastic off the outside revealing the maple and drill it out for a lamp. They had a long drill bit but I don't know how straight it went.

[Greg R Bradley]

A flex bit is going to be a real problem. 40" Timber bits are readily available which will get you 38" drilled straight. Milwaukee has a locking extension for those that fits the 7/16" hex. It adds another 12 or 18".

There is a 5/8"x40" in Amazon Warehouse for $41: https://www.amazon.com/gp/offer-list...A2L77EE7U53NWQ

[Lisa Starr]

I have a wood auger bit that I did something similar with. I first drilled the 32" or so that I needed in each of the timbers. I made a jig that slide over the end of the timber that helped keep me drilling straight. Once I had exhausted the depth of the drill, I welded (poorly) an 18" extension to it and finished each hole. I then drilled a hole perpendicular to the long bore into each piece. All 3 long bores were within a 1/4" of the planned path. Plenty close for fishing wires.