So apologies for the free advice request.

Need to connect a 50mm floplast waste pipe into a cast iron down pipe.

So my plan is a 56mm hole saw and in it goes, question is there a “adaptor” “seal” “grommet” thing?

Also any thing i should be concerned about?

Ta

question is there a “adaptor” “seal” “grommet” thing?

Google “Soil Pipe Boss connector”

Cheers Perchy

If you’re drilling into cast iron, drill the pilot hole first. You don’t want the holesaw to catch if you try to drill the pilot hole and large hole in one go. Cast iron, especially old cast iron, is really brittle and could crack.

Use a lubricant / coolant when you’re cutting the hole, again to stop it catching.

Video it in case it goes horribly wrong.

I have “previous” with cast iron…

Done this, didn’t die, even working from top of a ladder.

Well thos os an odd one…

My plan (if you could call it that) is to work from the inside of the house, knock out the bricks and then drill the cast iron soil pipe so the waste is not visible outside.

I know ambitious…

And then repair the brick from the inside?
That will look more of a mess than having a waste pipe outside!

Future maintenance nightmare.

Putting a “rodable” access point inside. I am big on access for maintenance says the bloke who has had to just dig up my stone flagged floor in the kitchen to repair a cold water leak… i rember 25 year’s ago the plumber saying it will be fine…

I have put service channels in for all futher pipes and electrical work in my house – dont like “buried” services.

The brick work cant be seen inside as its in a void.

I may post photos when done… good or bad

You’ll need a mechanical boss for cast iron, not strap on boss.

Use battery drill in 1st (slow) gear. Use lots of push behind the drill – you want cutting force with a low rpm for cast iron. Use a good hole saw like Bosch progressor. With enough force should take 30s top to drill. Squirt of wd40 or whatever’s to hand.

Like this https://www.screwfix.com/p/mcalpine-mechanical-pipe-boss-connector-black-32mm/25854?tc=HT9&ds_kid=92700055281954505&ds_rl=1249404&gclid=CjwKCAjw_Y_8BRBiEiwA5MCBJs7-YrTnJ9CbkbeyjjQx5W1QqPI7w03YKTu5khlkzOggpPXqE5uMPhoCbGMQAvD_BwE&gclsrc=aw.ds

You’ll need a mechanical boss for cast iron, not strap on boss

I scrolled all the way down hoping no one had beaten me to a strap on joke and you’ve ruined it with reality 🙁

Cheers goldfish