drilling cast iron?

[John Stumbles]

(For those who've been following the thread "taps for roll-top ci baths?" with barely-contained excitement here is the sequel* ;-)

Can anyone offer any advice on drilling holes (about 20 - 25mm dia) in a cast iron bath for taps holes? Step drill? Hole saw?

• having drawn a blank on suitable taps costing less than an arm & a leg it occurs to me to blank off the existing holes in the vertical surface of the bath and drill new ones in the roll-top horizontal surface. Since the bath is going to be resurfaced (not enamelled) a spot of mesh + car-body-filler before the resurfacing should do the trick.

[Grunff]

I've drilled cast iron before with bimetal hole saws with no problems - just take it slowly and it works fine.

[N. Thornton]

can you not find something at a reclaim yard?

[BigGuyUK]

car-body-filler

Yes just use a hole saw take it slow do not use any cooling Cutting Past As Cast Iron is self Lubricating BigGuyUK

[Ed Sirett]

I have used a grit edged hole saw on a CI soil stack. It was not quick but it did the job. So that is likely your best bet but you'll need to make a

7mm (?) guide hole first. I'd try sacrificing a 3mm HSS bit first then brooch (sp?) out with a TiN coated HSS bit.

I've not tried this but I would think that a light weight diamond hole saws intended for glass/tiles should make a neat job. But they are £70 for _one_ bit + accessories extra. (26mm diam). Also you don't need the hole that good.

Like wise a heavy duty diamond core drill is about £30 + bits; but you'd have to make a 12mm hole first. (28mm diam - which I think is the size you want for clearance on 3/4" BSP)

Cobalt alloy holesaw - Apparently suitable for the hardest metals.???

[N. Thornton]

Why not do it the old fashioned way and screw the taps to the wall instead? Far less work than carving CI up.

Regards, NT

[John Rumm]

For smaller holes the spear ended drills intended for tiles and ceramics also work well on cast. Might be a way of getting a pilot hole for something bigger...

[John Stumbles]

Planning to put the bath in the middle of the room

[Toby]

How about mounting them on standpipes then? You can put many taps on threaded standpipes if you can deal with the floor mounting and water feed, of course a BSM may be more tricky - where does the showerhead stow when not in use? Two more possibilities to add to your list... BSM103 at

more realistically,

[N. Thornton]

Visions of pipes coming down from the ceililng with taps on the end in mid air :) The taps would be the shower as well then

Regards, NT

[Jerry Built]

Aldi had some sets of those last week for =A315. I didn't buy one as I hardly need them...

Lucky not to hit a hard bit in the iron.. if you do hit a hard patch (white iron) then that's it, unless you have special tools.

J.B.