Enlarging a hole, how?

[GLFaria]

I need to install two ball catches, of the kind used in cabinet doors, in through holes in a piece of soft pine.

The body of the ball catch is 12.2mm in diameter.
I only have 12mm drills (helical, brad-point and Forstner). I doubt I could find a drill bit in 12.2mm. 1/2 " might do, but anyway I would rather not buy a new bit of a size I most likely will not use again.

I tried enlarging the hole on a trial piece with a round file. This did it, but am not really happy about the results.

Any ideas on the best way (or some way other than a file...) of enlarging a hole from 12mm to 12.2mm diameter?

Thanks
G.

 

[RogerP]

I'd get a 1/2" or 13mm Spade Flat Wood Drill Bit and grind the edges down slightly to make it 12.2mm.

They can be bought very cheaply and would only take a few minutes to modify.

Here's a cheap 13mm you could soon grind that down. Just make sure you do the sides equally.

http://tinyurl.com/k9uul3l] £1.29 inc postage.

 

[hansonread]

If you really want the best finish possible, then just buy a HSS bit at 12.2 mm. The time you are going to spend modifying a spade bit is daft considering the small outlay that buying the right bit in the first place.

 

[CHJ]

Regrind your 12mm drill with the web off centre and it will drill oversize.
You may have to have a couple of trials to get it spot on.

This is something often achieved without trying for someone new to hand sharpening of twist drills.

 

[Phil Pascoe]

It's only 0.2mm - get a bit of dowel about 10mm, glue some abrasive around it and use in a power drill.

 

[Racers]

Soft pine, metal catch, hammer, job done :wink:

Pete

 

[wizard]

Soft pine, metal catch, hammer, job done :wink:

Pete

You’re a carpenter then (hammer)

 

[Racers]

Takes one to know one (hammer) :wink:

Pete

 

[RobinBHM]

You could use a 12mm helical drill in a cordless but have it set to reverse reverse and go in and out of the hole until it is loose enough.

Or buy a 12.5mm drill bit.

Or use a technical adjustment tool for persuasion (hammer)

Or curse and buy a ball catch that is made to the correct size!

It seems surprising that the catch hasnt been made for either a standard metric 12.0mm or imperial 1/2" size (mind you it wouldn't be the first time!)

 

[GLFaria]

Thank you people, for all the advice.

I don't want to buy a new drill just for this job. The customer is me, or rather my 3 year old grandson. Although I prefer to make things the right way, sometimes I don´t mind being less than perfect 8).

I think I'll use the suggestion by phil.p - this reminds me I have a number of miniature drums for use with a Dremel clone. I don't like making this work free-hand (no 3D vision, trembling hands from medication), so I will put one of them on my drill press and see how it works. I'll let you know.

 

[hansonread]

Just checked with my supplier, I can order a pack of 5, 12.2 mm drill bits for £3.90 including the vat. Would you like me to send you one?

 

[Phil Pascoe]

12.2mm is 0.2 oversized. 0.2mm is four thousandths of an inch on the radius - I can't help thinking hard work is being made of this.

 

[hansonread]

I couldn't agree more, if you only have one hole to drill, and its in soft wood, and you don't need to get it out, just hit it, if not, buy a bit.

 

[nanscombe]

You could also make the hole slightly oversize and wrap something like gaffer tape around the catch to enlarge it to fit the hole.

 

[GLFaria]

12.2mm is 0.2 oversized. 0.2mm is four thousandths of an inch on the radius - I can't help thinking hard work is being made of this.

I must agree. As I said before, I will try something along the lines you proposed.
However, I must say people are being really nice giving this many suggestions. And I always like discussing different ways of getting things done, some of them I always keep in my "mind store" just in case they may prove helpful in another occasion.

Thanks

G.

 

[woodfarmer]

Screwfix do a 4-14mm cone drill that is excellent. used it to cut 12mmm holes for a bike sprocket I was making.

 

[nanscombe]

In the past I have used a half-round file, possibly with sand paper.

I found my smaller round file made the hole uneven, causing small shaped indentations, so I used a larger half round one by scraping around the inside, whilst following the shape, of the hole.

The larger size of the file prevented the creation of little divots.

 

[GLFaria]

Well, this did it fast and with a good finish.
It's from a kit I bought a couple years ago at LIDL which I had completely forgotten. Thank you, phil.p, it was your reply that reminded me of its existence