I want to make a couple of rod arm brackets out of 6mm plate.

They need a 20mm hole in them, what's the easiest way to drill a 20mm hole??

good hole saw, lots of lube!

quote:

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Originally posted by cloudy
good hole saw, lots of lube!

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Get a decent Starrett one, there's loads on the bay. not a cheapo B&Q set.
Will go through 6mm plate no probs. just take you time and as said use plenty of coolant.
Another dodge is to drill a 6mm hole for the cutter first, then use a bit of 6mm rod in the cutter instead of the drill bit that comes with it. This stops the drill from milling the hole out of round, if you are using a hand drill and gives a neater hole.

[Edited on 21/8/11 by Confused but excited.]

As all of the above + best to use a bit of hardwood under the work piece. Be aware even with "Confused but excited. method" hole saws tend to make the hole a bit oversize so don't rush it.

Alternatively use a 20mm blacksmith's drill ie a 20mm drlli with a reduced shank to fit in a 1/2" chuck see http://www.toolstation.com/shop/p55192



[Edited on 21/8/11 by britishtrident]

if you could get them to me ill drill them for you

Steve I'm nipping in to work tomorrow -[I know I know it is still the holidays ] but I'll have a rake through the trays and I'm fairly sure we will have something around 20 mm ex Royal Ordnance so won't be the Black spur crapper, will be over your way Wednesday to see folks so could drip it/them off / post through letter box etc I ' can bring you a few chunks of iroko too :0
Alternatively if it isn't a rush you could mark out plates and I'll bring them back over- we have some meaty pillar drills
atb
Mike

hole saw or rotabroch would be brill but not everyone has 1and expensive.

As Trident says blacksmiths bit every time.
Cheers,
Bob

To get a 20.00mm hole get them laser/waterjetted out and is by far the easiest if not cheapest way

Its sorted, thanks to Mike helping me

Found out a couple of things about my pillar drill