Hello,

I understand that 15mm, 22mm, 28mm, etc. refers to the external
diameter of copper pipe, but does 32mm and 40mm still refer to the
internal diameter of waste pipe?

I have some "32 mm" waste pipe but it is 35 mm in diameter. I would
like to drill a hole for this pipe to pass through. What hole saw
should I use? I suppose 35mm would be a tight fit. is 38 mm the next
size up? is that what plumbers use?

For future reference, what size would I use for 40mm pipe?

Thanks.

Fred wrote:
Hello,

I understand that 15mm, 22mm, 28mm, etc. refers to the external
diameter of copper pipe, but does 32mm and 40mm still refer to the
internal diameter of waste pipe?

I have some "32 mm" waste pipe but it is 35 mm in diameter. I would
like to drill a hole for this pipe to pass through. What hole saw
should I use? I suppose 35mm would be a tight fit. is 38 mm the next
size up? is that what plumbers use?

For future reference, what size would I use for 40mm pipe?

Thanks.
It is generally better to have some clearance for waste pipes rather
than trying to achieve a honeymoon fit. Expansion and contraction as hot
waste passes through can lead to creaks and clicks; leaving clearance
helps reduce this noise.

Bob

Bob Minchin wrote:
Fred wrote:
Hello,

I understand that 15mm, 22mm, 28mm, etc. refers to the external
diameter of copper pipe, but does 32mm and 40mm still refer to the
internal diameter of waste pipe?

I have some "32 mm" waste pipe but it is 35 mm in diameter. I would
like to drill a hole for this pipe to pass through. What hole saw
should I use? I suppose 35mm would be a tight fit. is 38 mm the next
size up? is that what plumbers use?

For future reference, what size would I use for 40mm pipe?

Thanks.
It is generally better to have some clearance for waste pipes rather
than trying to achieve a honeymoon fit. Expansion and contraction as
hot waste passes through can lead to creaks and clicks; leaving
clearance helps reduce this noise.

A typical small size specific 'plumbers holesaw set' contains 19, 22, 29,
38, 44, 57mm holesaws, so in your case 38 & 44.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Fri, 13 Jun 2008 12:29:44 +0000, Fred wrote:

I have some "32 mm" waste pipe but it is 35 mm in diameter. I would
like to drill a hole for this pipe to pass through. What hole saw
should I use? I suppose 35mm would be a tight fit. is 38 mm the next
size up? is that what plumbers use?

I use whichever size hole saw in my box looks big enough - and a bit over
if I can't guarantee that the hole will be in exactly the right place wrt
the pipe.


--
John Stumbles

What do you mean, talking about it isn't oral sex?

On Fri, 13 Jun 2008 16:32:02 GMT, "The Medway Handyman"
wrote:

A typical small size specific 'plumbers holesaw set' contains 19, 22, 29,
38, 44, 57mm holesaws, so in your case 38 & 44.

I'm guessing that the 19mm is for 15mm pipe with 2mm either side but
what is the 22mm saw for?

29mm for 22mm pipe would leave 3.5mm either side which is a gap almost
twice as big as that around the 15mm pipe.

Yet 38mm for a 35mm pipe leaves only 1.5mm either side of a 35mm pipe.

Why isn't there any consistency in gap size? I would have expected
them to follow a pattern such as pipe diameter + 4mm.

Or am I just thinking about this too much?

Thanks.

Fred wrote:
On Fri, 13 Jun 2008 16:32:02 GMT, "The Medway Handyman"
wrote:

A typical small size specific 'plumbers holesaw set' contains 19,
22, 29, 38, 44, 57mm holesaws, so in your case 38 & 44.

I'm guessing that the 19mm is for 15mm pipe with 2mm either side but
what is the 22mm saw for?

Microbore?

29mm for 22mm pipe would leave 3.5mm either side which is a gap almost
twice as big as that around the 15mm pipe.

Maybe its the possible expansion with hot water rather than the clearance.

Yet 38mm for a 35mm pipe leaves only 1.5mm either side of a 35mm pipe.

Why isn't there any consistency in gap size? I would have expected
them to follow a pattern such as pipe diameter + 4mm.

Or am I just thinking about this too much?

Sounds likely to me :-)


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk