Cutting Hole for Bathroom exhaust

jburchill

I need to cut a hole through a rim joist for a bathroom exhaust fan. Either 3" or 4" hole. I was looking at the 3" or 4" hole saw. But reading the specs on them they don't look deep enough to go through the rim joist and siding.

How do you get the hole saw to cut all the way through?

My guess would be to drill half way through and where the pilot hole is drill that all the way through. Then go to the other side and put the pilot in the hole I just made and then finish the cut.

Is that how its done?

Big Stud

That will do it. If you HAD to cut it from one side you can go as deep as the hole saw will go. Then chisel out the plug and go again from the same side,

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All the best to you and yours, Tom

joecaption

Is it also having to go through the siding? What type siding do you have?

Ironlight

If it were me I would drill a 1.5" hole with a wood boring bit, then spiral cut out to the desired OD with a sawzall. But if the pilot bit is deep enough to get through the joist and you have access to the other side...and the hole that would work fine and be most expedient.

jburchill

I have wood siding, so thats going to add more depth on cutting through. I think I'll try to get the pilot hole to go all the way through. Then go to the other side the try to much through.

If that doesn't punch through do to being to thick, I'll go the sawzall way and finish it that way.

thanks guys for the tips!!!

oldhouseguy

Just use a longer drill bit to drill your pilot hole, one that you are sure will go all the way through, then switch to your hole saw.

On one demo I saw, they drove a long nail all the way through to make sure the pilot hole was marked on both sides, then hammer the nail back through and then used hole saw from each side.

dwcopple

I am going to be doing this very soon too and need all the tips I can get. I have wood siding covered with vinyl siding that I need to go through...

jburchill

Wasn't as hard as I thought, from the inside I had a template of what the exhaust hole would look like. Drilled a hole from the middle of the template all the way through, then from the outside used a hole saw to cut through.

With the wood siding, cut through that then remove that from the hole saw then continue on through.

dwcopple

did you buy a holesaw, rent, or borrow one? I know I am only gonna use it once, so it seems pricey to buy one. Do they rent these?

jburchill

borrowed from a friend. He was actually there helping so I didn't mess up.lol...but yeah they are spendy just to use once.

dwcopple

Neighbor let me borrow his Lennox set. Went way better than I hoped for. Cut all but about 1/64 that I just tapped out with a hammer.

jburchill

You have a good drill to use? I had a dewalt 6.8 amp and that thing was starting to smoke. Worked good probably should of let up on it some.

dwcopple

used a 20v rigid lithium ion

firehawkmph

I use a 4 1/8" lennox hole saw. I have used an 18v dewalt drill and at times used a corded drill. If the hole saw is in good shape, you shouldn't need to push hard at all. Let the holesaw do the work. I drill a pilot hole all the way through usually from the inside out, just to make sure I'm where I should be. Drill carefully through vinyl siding, no pressure and slow speed. Also helps to do it on a warm day, not chilly weather. As you go through each wood layer, empty the plug out of the holesaw. Thickest part should be the joist if you are going through it. Lennox 4 1/8" holesaw- $25, plus the arbor - $18.
http://www.toolup.com/lenox_66l_4-18...FQXqnAodCWZMiA

http://www.toolup.com/lenox_3l_3l-hole-saw-arbor.aspx
Mike Hawkins

bubbler

+1 this is what I did.

I found a long bit, same size as my arbor bit on the hole saw. I leveled the drill and went straight through the house (from inside to outside).

Then I used hole saw from inside and then from outside using the pilot hole for my arbor bit.

This way you can also run the saw backwards when cutting the vinyl. I also taped mine up to try to minimize tearing, don't know how effective it was tho... in the end the hole was covered by the vent assembly.

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My advice is based on anecdotal knowledge or personal experience. I'm not a professional no matter how matter of factly I may say something
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