Drilling a hole...

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Cartus

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I need to accurately drill a hole in the bottom of an old galvanised steel bath to fit a plug hole into. I would expect to have to drill a hole of about 75mm or so (I’ll get the plug etc first).

Can anyone advise me about a suitable hole saw that would be up to the job as I don’t want to b****r up the bath and ruin it if I can help it. :(


Thanks.
 
I did this a long time ago but I forget. If it's got an enamel coating then I think it's a diamond coated holesaw which I used, but it was for taps. 75mm could be expensive!
 
gman said:
I did this a long time ago but I forget. If it's got an enamel coating then I think it's a diamond coated holesaw which I used, but it was for taps. 75mm could be expensive!
Click to expand...

You read my mind re: diamond coated to cut the enamel cleanly. Plus as I perceive it steel baths have a variable thickness ~ i.e. thicker in the sides and the lip as well as the plughole area...............most steel baths seem to flex more in the area away from the plughole 'zone'. Therefore IMO you need to support it well, possibly, including a wooden block under the drilling area.

Oh, and I wonder why a new plughole..............surely appropriate plumbing to utilise the current one???
 
Drilling enamel baths is going to be a nightmare, but as yours is galvanised it should be a whole ( punn intended) lot easier. You could try using a decent hole saw, drill it slowly or the blade will wobble as you start. You should be able to get a decent drill on line or even Screwfix/tool station etc, just be very patient whilst drilling it and drill a pilot hole first. Failing that, there is a manual drill that is used to cut holes in the sides of copper cylinders, it is a laborious way of doing it, but done properly you would get a cleaner hole, not only that they are fully adjustable so you could drill the exact diameter hole you need. Similar to this one, but you can get them for cutting metals.

https://www.toolstation.com/adjusta...FplXWLD751aNy4E6iy_TmVc0zv4I1f2BoCvzkQAvD_BwE
 
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Just a thought...

Unless the old galvanised bath has a recess for a plug hole, it won't drain properly.

Another thought...

Make sure you treat the cut edge with a suitable rust preventative (does "Galvafroid" still exist?).
 
Nod said:
Just a thought...

Unless the old galvanised bath has a recess for a plug hole, it won't drain properly.

Another thought...

Make sure you treat the cut edge with a suitable rust preventative (does "Galvafroid" still exist?).
Click to expand...

That's a name I've not heard of since I was an apprentice and had to paint the steel pipework with the stuff.
 
Almost any "decent" hole saw will do it, Screwfix do a set, just make sure you have the one with built-in pilot drill like this

https://www.screwfix.com/p/multi-material-plumbers-bi-metal-holesaw-set-9-pieces/3851V?tc=AA1&ds_kid=92700048793290430&ds_rl=1244066&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL56dKglJqkKmIAMBMi9pO6lsm-LYqV4ACtyk44EBwAlE_xYbsAtleRoCvl8QAvD_BwE&gclsrc=aw.ds

normal plugs are around 45/46mm ish, no idea about the whole size as never had to fit one, the kit includes 57mm so im guessing around that size ?
 
What is it then, a cast iron enamel bath or a galv tin bath because that really decides the correct hole cutter.
Any Starrett will do a tin bath easy, probably do a cast iron one too but I wouldn't want to be worrying about ruining it with enamel breakout.
And 75mm sounds big for a plughole..:)
 
mex said:
That's a name I've not heard of since I was an apprentice and had to paint the steel pipework with the stuff.
Click to expand...

Seems like it does still exist - at a price! I would guess that the less exorbitantly priced alternatives will do the same job. We used to use it to 'proof the edges of holes we'd drilled through trailer chassis.
 
The bath I’m talking about is identical to the one in the photo in Tori_T’s post above. I’m planning on using it as a shower tray in my narrowboat. I intend to build a box for it to sit in and to provide any clearance for drainage. I’d attempted to drill into galvanised steel before and found it difficult.

Thanks for the responses, Nod makes a good point in any galvanised steel drilled through will need rustproofing, I might have missed that.
 
Why not just get yourself a set like this and pump the water out instead? ;)



Joking aside, the base of these old wash tubs (as that's what they were sold as in their later days) wasn't all that strong, and certainly wouldn't stand the unsupported weight of an average adult human without buckling and subsequently parting company with the 'crimped on' metal sides. I think you'd need a good, thick (double 3/4 inch + ?) sheet of marine ply under the base to support it, and probably some form of rubber sheet between the two to take up any play between them? Even then, I wouldn't want to risk it in terms of potential for leaks. After all, bolting the bath to the supporting timber to fix it securely is going to the leak potential, and leaving it free is going to allow movement and put strain on the plug hole seals.

Then there's the irregular shape of the tin bath, unless you run a shower curtain around the bath to direct the shower spray into it (and you're thin as a rake to move around freely within such a confined space without the clammy shower curtain sticking to you) then you'll most likely have water going all over the place, and potentially running between the sides of the tin bath and any surrounding trim, which will cause mildew, rot and associated bad smells.

To be honest, while it seems a nice retro/industrial architecture idea, in practical terms I think you'd be better with a more conventional and purpose made shower tray/cubicle?
 
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Cartus said:
I intend to build a box for it to sit in and to provide any clearance for drainage.
Click to expand...

You'll still need to "joggle" the area around the plug'ole to get it to drain properly. Personally, I'd go down the small, purpose made shower tray route if I couldn't shower elsewhere. Boats are pretty bad as far as condensation goes so adding a shower's steam could cause problems.
 
Mr Badger said:
Why not just get yourself a set like this and pump the water out instead? ;)



Joking aside, the base of these old wash tubs (as that's what they were sold as in their later days) wasn't all that strong, and certainly wouldn't stand the unsupported weight of an average adult human without buckling and subsequently parting company with the 'crimped on' metal sides. I think you'd need a good, thick (double 3/4 inch + ?) sheet of marine ply under the base to support it, and probably some form of rubber sheet between the two to take up any play between them? Even then, I wouldn't want to risk it in terms of potential for leaks. After all, bolting the bath to the supporting timber to fix it securely is going to the leak potential, and leaving it free is going to allow movement and put strain on the plug hole seals.

Then there's the irregular shape of the tin bath, unless you run a shower curtain around the bath to direct the shower spray into it (and you're thin as a rake to move around freely within such a confined space without the clammy shower curtain sticking to you) then you'll most likely have water going all over the place, and potentially running between the sides of the tin bath and any surrounding trim, which will cause mildew, rot and associated bad smells.

To be honest, while it seems a nice retro/industrial architecture idea, in practical terms I think you'd be better with a more conventional and purpose made shower tray/cubicle?
Click to expand...

Thanks for that, I suspect you’re correct and I may resort to plan B and buy a small shower tray and use the bath as a planter!
 
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Nod said:
You'll still need to "joggle" the area around the plug'ole to get it to drain properly. Personally, I'd go down the small, purpose made shower tray route if I couldn't shower elsewhere. Boats are pretty bad as far as condensation goes so adding a shower's steam could cause problems.
Click to expand...
I think a small shower tray is the way to go. There is a shower already in the boat using a standard 3’ square tray which in our 30’ narrowboat is too big, but I would like to keep it for longer trips than just a night or so.
 
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