What drill bit do I need for making big holes?

[OM2]

I want to make upto 10cm in diameter in holes. Only need for wood.

What drill bit should I be searching for?

The ones I find are labelled for electricians + quite expensive.

I would love a clean cut hole...
But also is there some sort of rubber ring that I can put over to cover?

Most the holes will be for tables and making holes so I can feed wire through

Thanks

 

[Keithmac]

Google Holesaw..

 

[Notch7]

making holes so I can feed wire through

big wire then!

 

[TicTac]

You can get holesaws that are designed ti make access holes in floors etc, and you can then buy the covers to drop in place, but I'm not sure if this is exactly what you're after.

 

[Tigercubrider]

https://www.ebay.co.uk/i/1323199174...3D710-134428-41853-0%26rvr_id%3D1484763295657

100mm seems pretty big- buy the covers first, then the drill to fit

 

[KenGMac]

You could consider drilling smaller holes, each hole for say live feeds,, the other for Comms cabling and TV Cabling Etc makes for locating a suitable drill and insert cover easier?

Just a consideration, after all a 100 mm Dia. hole is a beast with a load of break out problems with the edges?

 

[magicmushroom666]

I'd use a holesaw like this:
https://www.screwfix.com/p/erbauer-bi-metal-holesaw-102mm/42986
Stick to the 1 piece ones like in the link, rather than the split multi size ones if your going to use it more than once!
You'll need to get the matching arbor as well.

 

[Tigercubrider]

If building from scratch. (I have built a lot of control desks)
You can space the work surface away from the wall and add a brush style draught excluder
Or a letter box one, they do make a 19" rack mount version

http://www.rackyrax.com/cable-manag...DN-dbf-Hn5yjvCqyCynA6AHAtQwjywPUaAkltEALw_wcB

 

[Deleted member 174758]

Just a consideration, after all a 100 mm Dia. hole is a beast with a load of break out problems with the edges?

You need to drill from one side first until the pilot bit breaks through, then finish drilling from the other side. Much better finish

The torque reaction on a 100mm holesaw calls for lower speed and extra care, as well as possibly a long side handle on the drill to avoid injury in the event of a "stick" (I use a Makita DHP480 cordless combi with a long side handle). Not advisable to use low power cordless drills unless you really want to burn the batteries out (by cooking them), I'd say. A drill press is really a better option if at all possible

 

[OM2]

thanks for the replies guys.
10cm? ok... maybe too big.

@JobAndKnock now you've got me worried!
i've got mango wood tables - they weigh an absolute ton.
i didn't think it would be a problem?
i dont want to go and buy a makita just for this!
i've got a bosch cordless drill - but if u say it's a challeging job... i don't want to put it to the test!

drill press - i could buy a drill clamp and use that?

@Tigercubrider letterbox looks great. i'll consider. but for the first desk... i need a hole.

EDIT just searched for 'desk hole for sockets'
bingo
i think the standard size is 80mm.
they're called Desk Table Grommet.
£1.50 delivered - crazy - the item MUST be more than 2.5cm = packet in Royal Mail.

 

[Nozzle]

If you want to produce quality holes in nice wood - don't use a [hole] saw... Use a Forstner bit (using backing timber to avoid break-out) or a router (with a collar & template)

Nozzle

 

[OM2]

@Nozzle thanks for the advice. Sounds good.
Backing timber... say if I'm drilling through... you are saying put a block of wood underneath?

Router? Can you show me what you mean with a pic or video?
Thanks

 

[Deleted member 174758]

thanks for the replies guys.
10cm? ok... maybe too big.

You finally said 80mm which is a lot easier to deal with - at 100mm and above it starts getting a much more difficult! On shop fits I drill out 50 to 75mm holes in counters quite a lot with just an 18 volt cordless and a side handle (yes, I use the big drill, but in the past I used smaller ones) - ideally you want to drill half way through from one side, and the rest from the other, pulling the saw back regularly to clean-out the gullets between the teeth (which are pretty small). The carbide tipped hole saws with 2- to 4-teeth are actually better in that respect and clog less easily. One thing to note about hole saws is that the hole it cuts will not be clean-sided, so your inserts will need to have a flange or lip which covers the poor surfaces of the insides of the hole. TBH it doesn't matter that much so long as the inserts have flanges (most cable tidy inserts do)

 

[rsgaz]

pulling the saw back regularly to clean-out the gullets between the teeth (which are pretty small).

Here's a tip for that, you can massively speed up the time taken to drill a worktop with a holesaw.

Just start the hole, maybe go 2mm deep.
Using an auger (say, 12mm), drill all the way through, so that this 12mm hole slightly overlaps the groove made by the holesaw, like this...

It gives the dust somewhere to go and then you can go all the way through in one go with the holesaw. Chipboard is very frustrating otherwise, it's not just the binding/clogging and having to keep stopping, but the resin in the chipboard begins to overheat and boil/burn!

Gaz

edit: but as said, once the arbor pokes out the bottom, drill upwards with the holesaw a little bit for a cleaner hole.

 

[OM2]

thanks guys.
@rsgaz - oooh that's an awesome tip

i'm a bit confused. what's better holesaw or Forstner drill bit?