Drilling holes in metal bigger than 13mm?

[mitchel.]

Hello,

Just wondering what's the best way to drill holes bigger than 13mm in 4mm metal up to 20mm I have to no three phase for a big pillar drill.

Currently using a step cutter

 

[WorkshopChris]

Holesaw
http://www.starrett.co.uk/shop/holesaws/
Other makes are available.

 

[MattH]

Mag drill with Rotabroches?

 

[waddycall]

Do you have a pillar drill? Why not just use blacksmiths reduced shank drills?

 

[zzr1200]

What the of metal angle or plate?

And what size holes?

I take it, its not aluminium......?????

 

[weldgauge]

Mag drill with Rotabroches?

this tbh... as long as its steel parts.

 

[WorkshopChris]

If using a rotabroach it must Depend how well the magnet holds with only 4 mm material underneath.

 

[weldgauge]

the broach should be fine on 4mm thick material. saying that i usually work of a steel bench which may help with that.

 

[Ton-up]

this tbh... as long as its steel parts.

If using a rotabroach it must Depend how well the magnet holds with only 4 mm material underneath.

Done loads of holes with Rotabroach cutters by G-clamping a steel plate to an ally box to hold the magnet!

 

[Kent]

Single phase pillar drill, don't get the issue I go up to 22mm fine on single phase with morse taper. Just last week did around 148 off 17mm holes through 10mm steel

in a hand drill its a toss up between hole saws (not duel pitch ones) and blacksmith drills. In 2mm - 5mm I should go hole saw though. Above that, depends but prefer the blacksmith drill generally not a great deal in it though

 

[gordon stephenson]

To what accuracy does the diameter need to be?

 

[paceman1]

you could turn the shank down so it fits the chuck

 

[NickyEng]

Magnetic drill with rotabroach cutter. A holesaw will do it but it will be very noisy and the vibration will send you bouncing round the workshop like bugs bunny

 

[Wozzaaah]

you could turn the shank down so it fits the chuck

Not if you don't have access to a lathe.
As Waddycall says, a Blacksmith's drill already has a reduced shank.

 

[paceman1]

sorry I didn't know that about black smiths drills

 

[Wozzaaah]

The shank is normally about 13mm but the actual drill sizes go fairly big, I know I've got a 19mm and I think I've got one that's 22mm.
Not recommended to be used hand-held though.

 

[wyn]

Rotabroach Mini cutters willl fit in a hand drill and should cut through 12mm when using a 20mm diameter cutter.

 

[Gareth0123]

Rotabroach Mini cutters willl fit in a hand drill and should cut through 12mm when using a 20mm diameter cutter.

They look to be very useful..... what kind of money is the set?

 

[brightspark]

blacksmiths drills -don't do any drill a favour in a half inch chuck - I have a set and rarely use them unless I have 2

 

[Tigman]

you can get Rotabroach bits to fit in 1/2" chuck they are very good in the small pillar drill

Have a look at Orbital Fasteners catalogue