Odd size rubber boss adaptor?

[JBPLUMBING]

I'm working on a bathroom. Cast Iron stack. I need to make use of an existing integrated connection. When I pulled out the old 40mm pipe the rubber adaptor that was on it is a strange size. It is about 1cm smaller in overall diameter than a normal rubber adaptor (it's about 50mm). It looks just like a normal one it's just thinner rubber) I can't use a normal adaptor (too big). No room for a boss and replacing the soil stack isn't really an option.
Any ideas?

ps Local merchants had never seen one, nor had bss.

 

[JBPLUMBING]

Left is a normal 40mm rubber boss adaptor, right is the odd size one I pulled out the cast stack.

 

[SimonJohns]

Could you get a bit of cooper in there. Do a cup joint and then a universal coupler on to that?

 

[JBPLUMBING]

Er isn't a cup joint for lead to lead?

 

[SimonJohns]

I'm sure you can do a joint that goes to copper. Not sure of the terminology

 

[tamz]

Why not just shove it back in with a 3" cutting of the old waste pipe and come off it with a multifit union

 

[JBPLUMBING]

The only thing can find on google is an oakum + lead joint... I don't have the materials to do that.

 

[JBPLUMBING]

The old rubber adaptor is not in good nick, it's split so I can't reuse it.

 

[tamz]

You will get the proper adaptor in Drain Center or PDM or Ashworths or whatever drainage merchants you have near you.
A flush pipe adaptor may do it if you are stuck.

 

[JBPLUMBING]

I bought the 'correct' size adaptor from the merchants (see pic above), it was too big. Aaargh!

 

[Billy Bob Bob]

I bought the 'correct' size adaptor from the merchants (see pic above), it was too big. Aaargh!

as tamz said got any drain centres near you? forget going to normal merchants

 

[tamz]

I bought the 'correct' size adaptor from the merchants (see pic above), it was too big. Aaargh!

The adaptor ypou bought fits polypipe and hepworth plastic bosses

 

[JBPLUMBING]

Thanks Tamz, I've sussed it. I bought a push fit 40mm boss adaptor from Wickes which was just right.

 

[JBPLUMBING]

Thanks for all the advice everyone.