enlarging a hole - Woodworking Talk

coondogger · 12-28-2007, 08:34 PM

Is there a trick for enlarging the diameter of a hole? How do you center the bit for the larger diameter hole?

joesdad · 12-28-2007, 08:48 PM

If it's a small hole (under an inch?) a step bit will work.
If it's a bigger hole. Hole saws work good.

slatron25 · 12-28-2007, 09:21 PM

Drill the larger hole in another piece of wood, center that hole over the smaller hole using it as a guide. You'll probably need to clamp it.

Bruce B · 12-28-2007, 10:28 PM

Coondogger.
welcome to our forum, Ron25 is right this is also the way I do it just make sure you are on center and you will have no problems you will have to clamp it.

Bruce.

BlockHead · 12-28-2007, 11:18 PM

Using a template as the others mention works really well. Just as an option, you could also plug the hole and re-drill it. I've used both methods a lot - the template is easier but I don't always have clamps or a scrap piece on hand.

coondogger · 12-29-2007, 12:06 AM

OK, I did some more investigating. Two hole saws on a single arbor.
The inner one is the same diameter as the original, smaller, hole. The outer saw is the diameter which you want to enlarge the hole to. Whaddya think?

TomD · 12-29-2007, 12:11 AM

I just cut a plug the same size as the original hole from scrap wood. Closely sized hole saws will not fit inside one another.

Tom

BlockHead · 12-29-2007, 12:19 AM

Quote:

Originally Posted by TomD

I just cut a plug the same size as the original hole from scrap wood. Closely sized hole saws will not fit inside one another.

Tom

You could make them fit together, only problem is getting them back apart.

Youngman · 12-29-2007, 12:21 AM

Quote:

Originally Posted by coondogger

OK, I did some more investigating. Two hole saws on a single arbor.
The inner one is the same diameter as the original, smaller, hole. The outer saw is the diameter which you want to enlarge the hole to. Whaddya think?

I like that idea, checked it out and the arbour does not have enough thread on the ones I have.
I vote for glue the hole plug back in the hole, then using the proper size hole saw. Glue is your friend....

BlockHead · 12-29-2007, 12:30 AM

One small problem is the plug that came out of the original hole is smaller because of the curf of the hole saw. The solution is to use a few shims to fill the extra space. But you have to keep it centered because of the hole from the pilot bit.

I have to mention that if you have a scrap piece of wood and a couple of clamps, the method mentioned by slatron25 is the simplest way to go. Even if you don't have a couple of clamps, you can press your weight against it to hold it in place. Just drill lightly till you get it started. Once you're about 1/4" into the wood the bit shouldn't jump out or wander or anything.

edp · 12-29-2007, 07:51 PM

but I have seen a couple of manufacturers that sell a mandrel especially for this problem. The larger saw mount with the smaller saw serving as a pilot. Pretty sure I saw one in the McFeeleys catalog.

Ed

woodman42 · 12-29-2007, 08:29 PM

Quote:

Originally Posted by slatron25

Drill the larger hole in another piece of wood, center that hole over the smaller hole using it as a guide. You'll probably need to clamp it.

Unless you just want to buy this fancy little tool for enlarging holes, slatron's idea works great.

mackem · 12-29-2007, 09:01 PM

Hope this helps

Joe Lyddon · 12-30-2007, 12:17 AM

That is a cool solution... I have seen it work... It IS cool! And simple!

Good illustrations!

Rob · 12-30-2007, 12:40 AM

I'm not sure what kind of bit you are using or if you are using a hole saw. Either way, if you chuck the original bit (smaller one) back in the drill and can get a center point from it on a piece of scrap that has been clamped, either from the twist bit, forstner or hole saw with the bit extended, this will give you a center mark to drill the larger size hole.
What am I missing here?

BlockHead · 12-30-2007, 01:11 AM

Hey Joe - I know this is off topic but I took a look at your website and found your story, how you got back into woodworking. Very inspiring, and I'm glad all worked out okay. Mostly though, I want to comment about the '20s style rocking chair.

My grandmother used to have one very similar, which I've long since forgotten about. I think a friend of my grandfather made it completely with hand tools. Anyway, Thanks for reminding me about it. I think I might attempt to make something similar sometime when all my tools are in the shop (most of my work is on-site), and I'll be sure to match the direction of the seat grain with the sides so I don't have to nail it back together every now and then.

Joe Lyddon · 12-30-2007, 02:21 AM

Quote:

Originally Posted by BlockHead

Hey Joe - I know this is off topic but I took a look at your website and found your story, how you got back into woodworking. Very inspiring, and I'm glad all worked out okay. Mostly though, I want to comment about the '20s style rocking chair.

My grandmother used to have one very similar, which I've long since forgotten about. I think a friend of my grandfather made it completely with hand tools. Anyway, Thanks for reminding me about it. I think I might attempt to make something similar sometime when all my tools are in the shop (most of my work is on-site), and I'll be sure to match the direction of the seat grain with the sides so I don't have to nail it back together every now and then.

Hi Blockhead!

Just be aware of the purpose of my website... I did NOT do all of those things... It's a "Collection" of what others have done that I really LIKE and want to maintain a record of everything I like, etc.

Good ideas, techniques, designs, jigs, etc.

I try to get as many questions asked/answered on the subjects so as NOT to leave any blank holes in the writeups.

Glad you like it... Yes, everything worked out OK; Thank God!
(... and I thank God everyday for everything!)

Joe Lyddon · 12-30-2007, 02:33 AM

Quote:

Originally Posted by Rob

I'm not sure what kind of bit you are using or if you are using a hole saw. Either way, if you chuck the original bit (smaller one) back in the drill and can get a center point from it on a piece of scrap that has been clamped, either from the twist bit, forstner or hole saw with the bit extended, this will give you a center mark to drill the larger size hole.
What am I missing here?

Look at the post by Makem... with the pictures...

A "Hole saw" is used to cut a hole of the desired size into a piece of scrap wood (larger than existing hole)... the hole is cut in a normal manner.

When THAT board is placed over the Old Smaller hole, carefully placed & clamped to have the same center point (by eye or markings), the center drill part of the hole saw is not needed because there is no wood there... instead, the bigger hole board serves as a guide to cut the larger hole over the smaller hole. Easily cut using the guide piece.

Works like a charm!

Hope I explained it OK...

mackem · 12-30-2007, 09:04 PM

Quote:

Originally Posted by Joe Lyddon

That is a cool solution... I have seen it work... It IS cool! And simple!

Good illustrations!

Thanks Joe, i have to admit that i didn't do the illustration's they were
given to me by someone else when i had the same problem as coondogger.

And you know what us woody's are like, we save everything in case it comes in useful.

Love your website by the way.