Drilling large holes for central vac


Staff member
So I am trying to get my central vac install going, and ran into yet another problem. The drill bit everyone recommends (including central vac manufactures) doesn't work at all for me. This is the bit in question:


The screw will go in the wood, but once the actual blade touches the wood, it gets stuck right away. I have tried this with a drill press, a new variable speed 2800rpm drill (tried slow speeds too), nothing makes this bit work. I have never had something like this happen before, so I figured I must be doing something wrong. I bought this bit new from Home Depot for $40, so I am not happy. I figured I would post here first before returning it. Are there known issues with these type of bits?
That's the only style bit I use for running central vac (or large bundles of cable in residential work). You need a heck of a drill to run it, though. Such as Milwaukee's Hole Hawg or, in my case, Rigid's version (don't recall the part #). I call my drill "the wrist breaker". The son of a gun is a LOT stronger than I am and when it binds it gets squirrelly. The bit itself is not the issue, the drill is. That bit will rip through studs like crazy and even "eat" nails...
This is the drill I got just for this project:


Are you saying that drill is too weak?

Probably. The specs on that drill do not show torque, which is what you really care about when purchasing a drill for boring. You are probably better off with a right angle drill for drilling through studs and joists, as it makes it much easier to get into tight spaces. A lot of sellers show Amp ratings, which don't really tell you how much drilling power they have. You would be better off with something like this:


Unfortunately, that drill is a fortune, and it you don't planning on using it again, it would not be worthwhile. You may want to consider renting one though.

If you do not need right angle, consider something like this:


I have one of these, and it bores through wood like it was butter. You can find one of them on eBay for around $50-$60.

Keep in mind, you should are more concerned with torque than speed. You also want to make sure you have a high quality drill bit (the one you purchased looks like a good pic).
I agree with Anthony... I think your drill is just too wimpy.

I've got a whole set of those bits in different sizes and use them all the time wilth the Milwaukee drill linked below:

If your hand drill just stalls and doesn't try to rip your arm off, it doesn't have enough power for the job. Like Anthony mentioned... a drill with enough gusto to use with these bits can be down right dangerous and will easily cause bodily harm when they bind up. Witnessed an unlucky plumber on a job a few weeks back who broke three fingers and dislocated his shoulder using the same setup I have.

These Milwaukee self feed bits go up to over 4" diameter and the larger they get, the more difficult they are to handle.

Check to see if you have a tool rental in your area. Likely you will and can just rent a good drill for about what you spent at Harbor Freight. Ask for something like I linked or a "Hole Hawg"... they'll know what your talking about.


EDIT: Looks like Sacedog & I were typing at the same time and he beat me to the punch.
This drill actually did hurt my arm at first, when I didn't bother installing the 2nd handle. It's a 6A motor, versus the 7A Milwaukee listed on that page, so I am surprised it doesn't work. Spending more money on a drill I won't use that much will be hard to justify, and the sad part is that I only have to drill 3 holes :/ I guess I better go check the tool rental place.
dan, at home depot the six amp firepower, by black and decker works. did a central vac myself weeks ago with it. its junk and cheap, like eighty bucks, but it worked. i will find the drill bit i used for you late tonight.

i wanted a high end drill but my biz partner wouldnt go for it insisting the cheap piece of crap black and decker would work , and it did. y ou mUST use the extra handle or itw ill break your arm, LOL. it actually does have power. wont last forever but thats what ebay is for, lol
Hi E,
. . . It's a 6A motor, versus the 7A Milwaukee listed on that page, so I am surprised it doesn't work. . .
As already mentioned, what matters is torque. And what really has the most effect on the torque is the gearbox. Notice that all of the recommended drills have multi-speed gearboxes. I suspect the the drill you bought is high-speed only.

I would bet that none of those better drills would have enough torque at their fastest speed either. I would also bet that that drill bit was designed for a slower speed than your typical drill bit.
Rocco has the correct answer here. The Milwaukee drill I use for these bits has a top speed 750 RPM in the high range and about half that in the low range (which is what I usually use for bits 2.5" and larger).

These drills are like tractors compared to most high speed drills that may have similar power, but are geared much higher.

Dan, the HoleHawg type drills have serious gear reduction to make crazy amounts of torque. The drill you have is too wimpy, but probably can be nursed if you are only talking about three holes. Take light passes or even build up free rev speed and try using some of the drill momentum to punch through. Harder the deeper it gets but for three holes, it'll work.
I'll throw my 2 cents in.

I agree with everyone else about your drill. If that bit gets stuck and your drill doesn't wrap your arms around the stud next to it, it's not going to work well.

The HF drill you linked to is a hammer drill, make sure you don't have it in hammer mode as that is not the way the bit is designed to be used.

My only problem with these bits is trying to use them on OSB (Orientated Strand Board), the big chunky plywood looking stuff. It clogs the bits like nobodies business.

I agree with everyone else about your drill. If that bit gets stuck and your drill doesn't wrap your arms around the stud next to it, it's not going to work well.


You got that right. The drill that I have (mentioned above), does not have any type of clutch on it, so when it gets stuck, it about rips your arm off. I wsaa drilling through concrete with it a few years back (yes, I know I should have had a hammer drill, but I didn't own one at the time), and the bit got stick while I was drilling. Unfortunately, I didn't let go in time, and my wrist got seriously torqued. It hurt for weeks after that.

For 3 holes just pay a gas contractor or electrician to do them for you.

One thing for sure to watch for here is safety !

Don't tie any extenson cord to the drill but leave it so it can pull apart.



These puppies are wrist and arm breakers.......