Any way to use a 12mm shank drill bit in a drill chuck that only accepts up to 10mm?

Submitted by CephasPetraPeter t3_10omqrt in DIY

Hi there,

I want to drill a couple of very simple holes through our brick walls to run some Ethernet cable outdoors and back in.

Sadly the 16mm drill bit I bought to do the job has a 12mm shank, and my hammer drill only fits up to 10mm.

I've been looking online but can't seem to find a way around this, but I'm thinking surely there's some sort of adaptor or convertor that should be able to hold a larger size bit? But maybe not!

Any advice very much appreciated! Thanks!

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extra_specticles t1_j6foihy wrote

You could buy a 3000 dollar metal lathe and pare the drill shaft down a bit.

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FeralCJ7 t1_j6fqxtp wrote

Seems like the most sensible option.

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extra_specticles t1_j6fserz wrote

I watch YouTube. Pretty sure rockler/kreg/sawstop/squarespace or nord vpn can supply them.

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86tuning t1_j6g67oa wrote

> You could buy a 3000 dollar metal lathe and pair the drill shaft down a bit.

a normal drill bit is tool steel and very difficult to cut. i spoze a percussion bit might be easier.

cheapest real option is to get the correct size drill.

if you were a real hack you could change the shank from round to triangular using a bench grinder to fit in the smaller drill machine.

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Shot_Boot_7279 t1_j6g8d73 wrote

Most drill shanks are slightly softer thane the flutes portion. I used to “pair” the down all the time!

Edit: in a pinch you could probably chuck in drill backwards and grind it against belt sander. I’ve done that as well at home with no pairing machine.

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Dramatic_Accountant6 t1_j6kgrw4 wrote

I have ground down large bits to a triangular shape to get them to fit.

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86tuning t1_j6krsei wrote

> I have ground down large bits to a triangular shape to get them to fit.

> if you were a real hack you could change the shank from round to triangular using a bench grinder

as have i, which is why i mentioned it lol. but we are hacks. in the truest sense of the word :)

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Graflex01867 t1_j6ftszt wrote

Can you rent a bigger drill for an afternoon?

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zayzay_919 t1_j6g8z15 wrote

that's a big hole for a hammer drill. you might have less trouble if you go rent a rotary hammer for an hour to pop your holes.

or you can use a smaller bit and add the connections after sending it through the hole. the cable is only around 6mm without the connector.

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CephasPetraPeter OP t1_j6fxjjb wrote

All fair suggestions, thanks guys!

I think I'm just going to bite the bullet and buy another 16mm masonry drill bit that DOES fit a 10mm chuck.

I'm aware using a cordless hammer drill is gonna take a while, but for just two holes a new bit seems better than buying a new rotary drill!

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zayzay_919 t1_j6k9k4c wrote

if you're going this route, go slow with it. once you get the bit overheated, it's done. and it will overheat very quickly.

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keestie t1_j6gtr1h wrote

Most North American big box hardware stores will let you rent tools like a hammer drill of the correct size.

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Mentalfloss1 t1_j6gkgz7 wrote

If you’ve not done it before, be very careful drilling into brick. If the bit gets stuck it can really mess up your hand/wrist/elbow/shoulder.

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PerspectivePure2169 t1_j6fz2et wrote

Reduced shank drill bit is what you want. Mcmaster Carr has them and everything else.

You can also chuck it backwards in a drill it does fit, and then spin it and grind the shank down, if you're careful to keep true it will work ok- a poor man's lathe.

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kjbenner t1_j6g64wy wrote

SDS and SDS plus shank diameter is 10mm, I've never tried it but maybe you could chuck one up in a regular chuck?

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MattyHurricane t1_j6g8oou wrote

How many chucks could a drill bit chuck if a drill bit could chuck a drill?

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Diligent_Nature t1_j6gftie wrote

I replaced a 10mm keyed chuck with a 13mm keyless one. It will cost more than buying the right bit, but will increase the chuck capacity for future projects.

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Killawife t1_j6io45h wrote

Just buy or rent another drill with a 12mm chuck. And while you are at it, get a proper hammer drill with sds socket.

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nicolasknight t1_j6fmaml wrote

Buy a corded one at Harbor Freight, drill your holes, return it.

There isn't a safe way to do this.

You CAN replace the head with an after market but it will cost you more than the cheap drill.

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