Drilling Hole in Log Wall

[AlanC37]

I need to make a 3.5 inch diameter hole through a log wall for cables and pipes for a big split type of heat pump. The total length, including plaster and siding, will be about 15 inches and the logs are about 12 inches thick. I have, so far, been unable to find a long enough drill at 3.5 inch diameter so am considering drilling a number of small holes (3/8 inch) and chiselling out the remains of the log. Might be a bit tough for an old guy so I am hoping someone could advise me of a better way. I'm sure big holes in logs often need to be drilled but don't know how. Any advice will be gratefully received. Thanks, Alan C37

[Lawrence]

Have you considered drilling from each side toward the center? It is better to drill a through hole, no doubt but I'm sure you can also measure as accurately as you can from each side and use a square against the building to guide your bit. After you put the pipe through you will probably use some type of caulk or foam anyway.

[Dean]

Good idea Lawrence,,I would use one of the smaller bits and drill through dead center then just follow that from both sides to meet in the middle..Drilling at a slight angle down from inside to out will prevent water from running in if the outside seal ever leaks.

[Goedjn]

4" soil auger bolted to your pickup truck?

[N8N]

I agree, I would drill through the wall with a lampmaker's bit and then use that as a guide to follow.

good luck

nate

[GROVER]

Alan, If you drill with a 3/8" bell hanger drill you lose the center of the hole. This will make it very diffiicult to use a bit with a center worm. I would suggest you us a full size Forstner bit with some extension rod between the bit and the drill. You will also be well served by a half inch drill motor. I don't think most 1/4"drills are up to such a task. The Forstner will also leave a smooth bore. Joe G

[Steve B]

A company named Bosworth makes large mortise and tenon shaping tools for log applications. They may have something. Try googling for log tools. In this world of specialization, someone's gotta make something like that, even if it's a huge Forstner.

Steve

[Jim Yanik]

"Steve B" wrote in news:_FwQh.90605$ [e-mail]:

IIRC,they make 3' Forstner bits.You would need an extension shaft to drive it deep,though,and a powerful drill,like a HoleHawg.

[Harry K]

Going for cheap, use a "Speedbore" with an extension. Probably cheaper than a lampmaker's bit and the speedbore can be a reasonable size. A 3/8 drill would handle around 1 1/2" one or larger.

Harry K

[AlanC37]

[Steve]

"AlanC37" wrote in news:4613a31d$0$16316$ [e-mail]:

Use a drill bit extender. Here's a site with a variety.

[mm]

You really need 3.5 inches?

[AlanC37]

The equipment has a 3.5 inch diameter pipe to be used as a sleeve through the wall. I guess I don't have to use it if it isn't necessary though and I could use a bit of plastic tube of a smaller diameter. The next model down in size (12000Btu/hr) needs only a 2.56 inch hole. Thanks for the suggestion. I'll check what I need for two insulated pipes (3/8 inch and

5/8 inch OD copper) plus a bunch of electrical cables and a 3/4 inch drain pipe.

[AlanC37]

2 inch hole is a bit too small but a 3 inch one will work fine. A bit easier to do I hope. Thanks again, Alan C