How do I enlarge an existing hole

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Forum topic by EAGLE posted 09-03-2008 10:51 AM 26888 views 0 times favorited 20 replies Add to Favorites Watch
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63 posts in 3910 days

09-03-2008 10:51 AM

Does anyone out there know of a jig or tool than can make say…. a 1” hole and make it a 1-5/8” hole or a 1-3/4” hole and make it a 2-1/8” hole if so please let me know. Thanx, your fellow LJ Patrick

20 replies so far

View NY_Rocking_Chairs's profile


518 posts in 3795 days

#1 posted 09-03-2008 11:02 AM

You could clamp the piece of wood to the drill press and use a hole saw. However, those sizes might not be available.

You could cut a hole 1/8” larger, get a router with the guide bushing and route the new hole…

-- Rich, anybody want a peanut?

View Scott Bryan's profile

Scott Bryan

27250 posts in 4020 days

#2 posted 09-03-2008 12:13 PM

One method that I have used with door lock sets, with your example above, is to drill a 1 5/8th hole in a piece of 1x scrap, center it over the 1” hole and clamp it in place. This will keep the hole saw on track and let you enlarge the existing hole. You might also want to put a backer behind the piece being drilled to prevent blowout.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View Steve2's profile


75 posts in 3769 days

#3 posted 09-03-2008 12:44 PM

Center hole on drill press if possible. #2 as the other note, make a jig and center it, and yes those sizes should be readily avialable – they are here.

-- Regards, Steve2

View lew's profile


12424 posts in 3953 days

#4 posted 09-03-2008 03:15 PM

I had a bunch of interior doors that my wife want to replace the knob/latch. Bought new ones before taking off the old ones. Discovered that door hardware from 50 years ago used a smaller hole. This was before the Opp Bit. Used a hole saw to make plugs the diameter of the original hole. Glued them in place. When dried, re-drilled with a larger sized hole saw. The bit for the second drilling followed the hole made by the hole saw drill bit when cutting the plug and everything lined up.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Dick, & Barb Cain's profile

Dick, & Barb Cain

8693 posts in 4497 days

#5 posted 09-03-2008 05:24 PM

I’d plug it with a 1” dowel, & re-drill it.

-- -** You are never to old to set another goal or to dream a new dream ****************** Dick, & Barb Cain, Hibbing, MN.

View John Gray's profile

John Gray

2370 posts in 4083 days

#6 posted 09-03-2008 05:46 PM

Take the piece with your hole in it to the drill press. Use the bit/saw you used to drill the original. Put bit in chuck center the piece around the drill bit and securely clamp it in that position then replace the smaller bit/saw with the new size bit/saw you want the hole to be in drill away. The new hole will be centered on the original hole.

-- Only the Shadow knows....................

View FJPetruso's profile


326 posts in 3908 days

#7 posted 09-03-2008 07:28 PM

I was thinking of the Oops! bit like DaveR.. But instead of buying the bit you could chuck a piece of 1” dowel in a lathe & drill a pilot hole with the lathe that would be centered & glue the dowel with the small centered hole in the original hole Then use the size hole saw that you desire or one of those adjustable circle/hole cutting bits.

-- Frank, Florissant, Missouri "The New Show-Me Woodshop"

View Brent Powers's profile

Brent Powers

19 posts in 3784 days

#8 posted 09-03-2008 07:41 PM

Maybe I’m missing something, but why couldn’t you….

1.) clamp a piece of hardboard to the back of the 1” hole.
2.) use the 1” hole saw to make the center hole in the hardboard
3.) use the hole in the hardboard to locate the 1-5/8” hole saw

View Grumpy's profile


24629 posts in 4049 days

#9 posted 09-04-2008 01:25 AM

I’m with Dick, that is how I would do it.

-- Grumpy - "Always look on the bright side of life"- Monty Python

View sIKE's profile


1271 posts in 3952 days

#10 posted 09-04-2008 02:38 AM

How about a 1 5/8 forstner bit on a drill press. Center it up and press down…

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

View Karson's profile


35146 posts in 4598 days

#11 posted 09-04-2008 02:41 AM

I’d drill the correct hole size in another board and then clamp it over top of the existing, incorrect one and drill away using the new board to keep your bit in alignment.

I’ve done that when I need a step hole in a board and use multiple forstner bits to cut them. You drill the deeper hole first and then use a guide block to align up the other drills and to drill them on top of the first hold.

This example was drilling a hole for a “T” nut and for a plug hole for the T-nut to be hidden. One for the plug, one for the t-nut and 1 for the bolt to go into the t-nut.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia †

View FJPetruso's profile


326 posts in 3908 days

#12 posted 09-05-2008 06:18 AM

Looks like we all offer a lot of good ideas but it kinda depends on how accessable the hole is, what kind of tools Patrick has available to use & how accurate he must be in locating the hole. Good Luck Patrick

-- Frank, Florissant, Missouri "The New Show-Me Woodshop"

View dapix's profile


1 post in 3910 days

#13 posted 09-05-2008 09:04 AM

Hole saws are available in that size, I would use my drill press with a template and lock all on the press bed.

View Paul M Cohen's profile

Paul M Cohen

86 posts in 3976 days

#14 posted 09-05-2008 11:15 AM

Try a router with a rabbit bit, rest the bearing on the existing hole and the bit will make part of the hole the correct size. Then follow up with a template bit using the now correct hole on top to make the rest of the hole the same diameter.

-- Paul, Beaverton OR,

View motthunter's profile


2141 posts in 3997 days

#15 posted 09-05-2008 12:14 PM

A drill press is the best solution if you have one and the proper bit. If not,the router technique described above would be my second option.

-- making sawdust....

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